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Virk AS, Harris ZB, Arbab MH. Design and characterization of a hyperbolic-elliptical lens pair in a rapid beam steering system for single-pixel terahertz spectral imaging of the cornea. OPTICS EXPRESS 2023; 31:39568-39582. [PMID: 38041275 DOI: 10.1364/oe.496894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 10/10/2023] [Indexed: 12/03/2023]
Abstract
Terahertz (THz) time-domain spectroscopy has been investigated for assessment of the hydration levels in the cornea, intraocular pressure, and changes in corneal topography. Previous efforts at THz imaging of the cornea have employed off-axis parabolic mirrors to achieve normal incidence along the spherical surface. However, this comes at the cost of an asymmetric field-of-view (FOV) and a long scan time because it requires raster-scanning of the collimated beam across the large mirror diameter. This paper proposes a solution by designing a pair of aspheric lenses that can provide a larger symmetric spherical FOV (9.6 mm) and reduce the scan time by two orders of magnitude using a novel beam-steering approach. A hyperbolic-elliptical lens was designed and optimized to achieve normal incidence and phase-front matching between the focused THz beam and the target curvature. The lenses were machined from a slab of high-density polyethylene and characterized in comparison to ray-tracing simulations by imaging several targets of similar sizes to the cornea. Our experimental results showed excellent agreement in the increased symmetric FOV and confirmed the reduction in scan time to about 3-4 seconds. In the future, this lens design process can be extended for imaging the sclera of the eye and other curved biological surfaces, such as the nose and fingers.
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Margheri G, Del Rosso T. Long-Focusing Device for Broadband THz Applications Based on a Tunable Reflective Biprism. MICROMACHINES 2023; 14:1939. [PMID: 37893376 PMCID: PMC10609471 DOI: 10.3390/mi14101939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/11/2023] [Accepted: 10/14/2023] [Indexed: 10/29/2023]
Abstract
THz radiation has assumed great importance thanks to the efforts in the development of technological tools used in this versatile band of the electromagnetic spectrum. Here, we propose a reflective biprism device with wavelength-independent long-focusing performances in the THz band by exploiting the high thermo-mechanical deformation of the elastomer polydimethylsiloxane (PDMS). This deformation allows for achieving significant optical path modulations in the THz band and effective focusing. The surface of a PDMS layer is covered with a gold thin film acting as a heater thanks to its absorption of wavelengths below ~500 nm. An invariance property of the Fresnel integral has been exploited to experimentally verify the THz performances of the device with an ordinary visible laser source, finding excellent agreement with the theoretical predictions at 1 and 3 THz. The same property also allowed us to experimentally verify that the reflective biprism focus has a longitudinal extension much greater than that exhibited by a benchmark convex cylindrical mirror with the same optical power. The device is thermo-mechanically stable up to a heating power of 270 mW, although it might be potentially exploited at higher powers with minor degradation of the optical performances.
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Affiliation(s)
- Giancarlo Margheri
- Institute for Complex Systems of National Council of Researches of Italy, Separate Location of Sesto Fiorentino, Via Madonna del Piano, 50019 Sesto Fiorentino, Florence, Italy
| | - Tommaso Del Rosso
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, Rio de Janeiro 22451-900, Brazil;
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3
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Xu K, Harris ZB, Arbab MH. Polarimetric imaging of back-scattered terahertz speckle fields using a portable scanner. OPTICS EXPRESS 2023; 31:11308-11319. [PMID: 37155769 PMCID: PMC10316681 DOI: 10.1364/oe.482733] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 05/10/2023]
Abstract
Speckle patterns observed in coherent optical imaging reflect important characteristic information of the scattering object. To capture speckle patterns, angular resolved or oblique illumination geometries are usually employed in combination with Rayleigh statistical models. We present a portable and handheld 2-channel polarization-sensitive imaging instrument to directly resolve terahertz (THz) speckle fields in a collocated telecentric back-scattering geometry. The polarization state of the THz light is measured using two orthogonal photoconductive antennas and can be presented in the form of the Stokes vectors of the THz beam upon interaction with the sample. We report on the validation of the method in surface scattering from gold-coated sandpapers, demonstrating a strong dependence of the polarization state on the surface roughness and the frequency of the broadband THz illumination. We also demonstrate non-Rayleigh first-order and second-order statistical parameters, such as degree of polarization uniformity (DOPU) and phase difference, for quantifying the randomness of polarization. This technique provides a fast method for broadband THz polarimetric measurement in the field and has the potential for detecting light depolarization in applications ranging from biomedical imaging to non-destructive testing.
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Affiliation(s)
- Kuangyi Xu
- Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
| | - Zachery B. Harris
- Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
| | - M. Hassan Arbab
- Department of Biomedical Engineering, State University of New York at Stony Brook, Stony Brook, New York 11794, USA
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4
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Chen A, Harris ZB, Virk A, Abazari A, Varadaraj K, Honkanen R, Arbab MH. Assessing Corneal Endothelial Damage Using Terahertz Time-Domain Spectroscopy and Support Vector Machines. SENSORS (BASEL, SWITZERLAND) 2022; 22:9071. [PMID: 36501773 PMCID: PMC9735956 DOI: 10.3390/s22239071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 06/17/2023]
Abstract
The endothelial layer of the cornea plays a critical role in regulating its hydration by actively controlling fluid intake in the tissue via transporting the excess fluid out to the aqueous humor. A damaged corneal endothelial layer leads to perturbations in tissue hydration and edema, which can impact corneal transparency and visual acuity. We utilized a non-contact terahertz (THz) scanner designed for imaging spherical targets to discriminate between ex vivo corneal samples with intact and damaged endothelial layers. To create varying grades of corneal edema, the intraocular pressures of the whole porcine eye globe samples (n = 19) were increased to either 25, 35 or 45 mmHg for 4 h before returning to normal pressure levels at 15 mmHg for the remaining 4 h. Changes in tissue hydration were assessed by differences in spectral slopes between 0.4 and 0.8 THz. Our results indicate that the THz response of the corneal samples can vary according to the differences in the endothelial cell density, as determined by SEM imaging. We show that this spectroscopic difference is statistically significant and can be used to assess the intactness of the endothelial layer. These results demonstrate that THz can noninvasively assess the corneal endothelium and provide valuable complimentary information for the study and diagnosis of corneal diseases that perturb the tissue hydration.
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Affiliation(s)
- Andrew Chen
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Zachery B. Harris
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Arjun Virk
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Azin Abazari
- Department of Ophthalmology, Renaissance School of Medicine, 101 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Kulandaiappan Varadaraj
- Department of Physiology and Biophysics, Renaissance School of Medicine, 101 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Robert Honkanen
- Department of Ophthalmology, Renaissance School of Medicine, 101 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Mohammad Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
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5
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Foroughimehr N, Vilagosh Z, Yavari A, Wood A. Investigating the Impact of Synchrotron THz Radiation on the Corneal Hydration Using Synchrotron THz-Far Infrared Beamline. SENSORS (BASEL, SWITZERLAND) 2022; 22:8261. [PMID: 36365959 PMCID: PMC9658370 DOI: 10.3390/s22218261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Due to increasing interest in imaging, industrial, and the development of wireless communication operating at THz frequencies, it is crucial to ascertain possible health impacts arising from exposure to THz radiation. This paper reports on the pilot study of transmittance and absorbance spectra of the porcine cornea following THz frequency irradiation at a synchrotron THz/Far-IR beamline. The exposure period was 4 hours. One cornea was exposed to the radiation, with a second cornea acting as a control. An Attenuated Total Reflection (ATR) apparatus was used, and the frequency range of 2.4 to 8 THz was selected to evaluate any changes. It was found that the synchrotron THz radiation intensities are too low to produce induced corneal injury, but may lead to subtle changes in the state of water. Our results suggest that THz spectroscopy is a promising modality for corneal tissue hydration sensing.
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Affiliation(s)
- Negin Foroughimehr
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| | - Zoltan Vilagosh
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| | - Ali Yavari
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Melbourne, VIC 3122, Australia
| | - Andrew Wood
- School of Health Sciences, Swinburne University of Technology, Melbourne, VIC 3122, Australia
- Australian Centre for Electromagnetic Bioeffects Research, Swinburne University of Technology, Melbourne, VIC 3122, Australia
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6
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Zarrinkhat F, Lamberg J, Tamminen A, Baggio M, Nefedova I, Ala-Laurinaho J, Khaled EEM, Rius J, Romeu J, Taylor Z. Vector spherical harmonic analysis and experimental validation of spherical shells illuminated with broadband, millimeter wave Gaussian beams: applications to corneal sensing. BIOMEDICAL OPTICS EXPRESS 2022; 13:3699-3722. [PMID: 35991916 PMCID: PMC9352287 DOI: 10.1364/boe.456613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Coupling to longitudinal modes of thin spherical shells, under Gaussian-beam illumination, was explored with a theoretical method based on Fourier-optics analysis and vector spherical harmonics and was scrutinized with an experimental setup. For the theory part, the illumination frequency band was fixed between 100-600 GHz and the outer spherical shell radius of curvature and thickness are 7.5 mm and 0.5 mm, respectively. The shell material was either the lossless cornea or an aqueous effective media representing the cornea. Six different beam-target strategies were introduced being potential candidates for maximum coupling. Two dispersion-tuned beam ensembles with strongly frequency-dependent phase center location have been created with a fixed incident beam 1/e radius and radius of curvature called forward strategies. These computations of different alignments were continued with four beam ensembles of frequency-invariant phase center, constructed from fits to experimental data, oriented at four different axial locations with respect to the spherical shell center of curvature, they are called reverse strategies. Coupling efficiency for all strategies was calculated for different targets including perfect electrical conductor (PEC) sphere, PEC core covered by a cornea loss-free layer and cornea. All scattering strategies contrasted to scattering from equivalent planar targets as a reference with maximum coupling. The results show that, under an ideal calibration, forward strategies are a closer approximation to the plane-wave condition for the cornea. An experimental setup was assembled to explore the simulation approach in a frequency range between 220 GHz to 330 GHz. Two different quartz samples with permittivity of 4.1 were mounted on a water core, acting for a cornea. The first and second quartz radius and thickness were 7.5 mm and 0.5 mm and 8 mm and 1 mm, respectively. An adequate agreement between theory and experiment was confirmed. A particle optimisation swarm algorithm was applied to extract the thickness and permittivity of quartz from the measured back-scattered field for reverse strategies.
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Affiliation(s)
- Faezeh Zarrinkhat
- CommSensLab, Technical University of Catalonia/UPC, Barcelona 08034, Spain
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Joel Lamberg
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Aleksi Tamminen
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Mariangela Baggio
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Irina Nefedova
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Juha Ala-Laurinaho
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
| | - Elsayed E. M. Khaled
- Department of Electrical Engineering, Assiut University, Assiut 71515, Egypt
- High Institute of Engineering and Technology, Sohag 82524, Egypt
| | - Juan Rius
- CommSensLab, Technical University of Catalonia/UPC, Barcelona 08034, Spain
| | - Jordi Romeu
- CommSensLab, Technical University of Catalonia/UPC, Barcelona 08034, Spain
| | - Zachary Taylor
- Department of Electronics and Nanoengineering, Millilab, Aalto University, Espoo 02150, Finland
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7
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Osman OB, Harris ZB, Zhou JW, Khani ME, Singer AJ, Arbab MH. In Vivo Assessment and Monitoring of Burn Wounds Using a Handheld Terahertz Hyperspectral Scanner. ADVANCED PHOTONICS RESEARCH 2022; 3:2100095. [PMID: 36589697 PMCID: PMC9797155 DOI: 10.1002/adpr.202100095] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The accuracy of clinical assessment techniques in diagnosing partial-thickness burn injuries has remained as low as 50-76%. Depending on the burn depth and environmental factors in the wound, such as reactive oxygen species, inflammation, and autophagy, partial-thickness burns can heal spontaneously or require surgical intervention. Herein, it is demonstrated that terahertz time-domain spectral imaging (THz-TDSI) is a promising tool for in vivo quantitative assessment and monitoring of partial-thickness burn injuries in large animals. We used a novel handheld THz-TDSI scanner to characterize burn injuries in a porcine scald model with histopathological controls. Statistical analysis (n= 40) indicates that the THz-TDSI modality can accurately differentiate between partial-thickness and full-thickness burn injuries (1-way ANOVA, p< 0.05). THz-TDSI has the potential to improve burn care outcomes by helping surgeons in making objective decisions for early excision of the wound.
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Affiliation(s)
- Omar B Osman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Zachery B Harris
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Juin W Zhou
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Mahmoud E Khani
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Adam J Singer
- Department of Emergency Medicine, Renaissance School of Medicine at Stony Brook University, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - M Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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8
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Zarrinkhat F, Baggio M, Lamberg J, Tamminen A, Nefedova I, Ala-Laurinaho J, Khaled EEM, Rius JM, Romeu J, Taylor Z. Calibration Alignment Sensitivity in Corneal Terahertz Imaging. SENSORS 2022; 22:s22093237. [PMID: 35590925 PMCID: PMC9105978 DOI: 10.3390/s22093237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/12/2022] [Accepted: 04/20/2022] [Indexed: 11/16/2022]
Abstract
Improving the longitudinal modes coupling in layered spherical structure contributes significantly to corneal terahertz sensing, which plays a crucial role in the early diagnosis of cornea dystrophies. Using a steel sphere to calibrate reflection from the cornea sample assists in enhancing the resolution of longitudinal modes. The requirement and challenges toward applying the calibration sphere are introduced and addressed. Six corneas with different properties are spotted to study the effect of perturbations in the calibration sphere in a frequency range from 100 GHz to 600 GHz. A particle-swarm optimization algorithm is employed to quantify corneal characteristics considering cases of accurately calibrated and perturbed calibrated scenarios. For the first case, the study is carried out with signal-to-noise values of 40 dB, 50 dB and 60 dB at waveguide bands WR-5.1, WR-3.4, and WR-2.2. As expected, better estimation is achieved in high-SNR cases. Furthermore, the lower waveguide band is revealed as the most proper band for the assessment of corneal features. For perturbed cases, the analysis is continued for the noise level of 60 dB in the three waveguide bands. Consequently, the error in the estimation of corneal properties rises significantly (around 30%).
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Affiliation(s)
- Faezeh Zarrinkhat
- CommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, Spain; (J.M.R.); (J.R.)
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
- Correspondence:
| | - Mariangela Baggio
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
| | - Joel Lamberg
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
| | - Aleksi Tamminen
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
| | - Irina Nefedova
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
| | - Juha Ala-Laurinaho
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
| | - Elsayed E. M. Khaled
- Department of Electrical Engineering, Assiut University, Assiut 71515, Egypt;
- High Institute of Engineering and Technology, Sohag 82524, Egypt
| | - Juan M. Rius
- CommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, Spain; (J.M.R.); (J.R.)
| | - Jordi Romeu
- CommSensLab, Technical University of Catalonia/UPC, 08034 Barcelona, Spain; (J.M.R.); (J.R.)
| | - Zachary Taylor
- Department of Electronics and Nanoengineering, Millilab, Aalto University, 02150 Espoo, Finland; (M.B.); (J.L.); (A.T.); (I.N.); (J.A.-L.); (Z.T.)
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9
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Osman OB, Harris ZB, Khani ME, Zhou JW, Chen A, Singer AJ, Hassan Arbab M. Deep neural network classification of in vivo burn injuries with different etiologies using terahertz time-domain spectral imaging. BIOMEDICAL OPTICS EXPRESS 2022; 13:1855-1868. [PMID: 35519269 PMCID: PMC9045889 DOI: 10.1364/boe.452257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 05/22/2023]
Abstract
Thermal injuries can occur due to direct exposure to hot objects or liquids, flames, electricity, solar energy and several other sources. If the resulting injury is a deep partial thickness burn, the accuracy of a physician's clinical assessment is as low as 50-76% in determining the healing outcome. In this study, we show that the Terahertz Portable Handheld Spectral Reflection (THz-PHASR) Scanner combined with a deep neural network classification algorithm can accurately differentiate between partial-, deep partial-, and full-thickness burns 1-hour post injury, regardless of the etiology, scanner geometry, or THz spectroscopy sampling method (ROC-AUC = 91%, 88%, and 86%, respectively). The neural network diagnostic method simplifies the classification process by directly using the pre-processed THz spectra and removing the need for any hyperspectral feature extraction. Our results show that deep learning methods based on THz time-domain spectroscopy (THz-TDS) measurements can be used to guide clinical treatment plans based on objective and accurate classification of burn injuries.
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Affiliation(s)
- Omar B. Osman
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Zachery B. Harris
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Mahmoud E. Khani
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Juin W. Zhou
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Andrew Chen
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - Adam J. Singer
- Renaissance School of Medicine at Stony Brook University, Department of Emergency Medicine, 101 Nicolls Rd., Stony Brook, NY 11794, USA
| | - M. Hassan Arbab
- State University of New York at Stony Brook, THz Biophotonics Laboratory, Department of Biomedical Engineering, 101 Nicolls Rd., Stony Brook, NY 11794, USA
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10
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Feng W, Wei S, Zheng Y, Wang C, Cao J. Theoretical Analysis of Terahertz Frequency Multiplier Based on Semiconductor Superlattices. NANOMATERIALS 2022; 12:nano12071114. [PMID: 35407230 PMCID: PMC9000275 DOI: 10.3390/nano12071114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 03/22/2022] [Accepted: 03/24/2022] [Indexed: 11/16/2022]
Abstract
We propose a terahertz frequency multiplier based on high order harmonic generation in a GaAs-based miniband superlattice driven by an electric field. The performance of the frequency multiplier is analyzed using the balance equation approach, which incorporates momentum and energy relaxation processes at different lattice temperatures. It is found that the generated high-order harmonic power is sensitive to temperature changes. The peak power appears around resonance between driving terahertz frequency and intrinsic Bloch frequency. In the presence of the magnetic field, the peak power shifts towards a stronger static electric field region. The simulated results about the dependence of the second and third harmonic powers on a DC electric field are in qualitative consistence with the experiments. The proposed terahertz frequency multiplier based on semiconductor superlattice, being compact and efficient, is provided as a good candidate for terahertz wave generation.
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Affiliation(s)
- Wei Feng
- School of Physics and Electronic Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China; (W.F.); (S.W.)
| | - Shuting Wei
- School of Physics and Electronic Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China; (W.F.); (S.W.)
| | - Yonghui Zheng
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
| | - Chang Wang
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
- Correspondence: (C.W.); (J.C.)
| | - Juncheng Cao
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
- Key Laboratory of Terahertz Solid-State Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, China
- Correspondence: (C.W.); (J.C.)
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11
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Supervised machine learning for automatic classification of in vivo scald and contact burn injuries using the terahertz Portable Handheld Spectral Reflection (PHASR) Scanner. Sci Rep 2022; 12:5096. [PMID: 35332207 PMCID: PMC8948290 DOI: 10.1038/s41598-022-08940-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/04/2022] [Indexed: 12/21/2022] Open
Abstract
We present an automatic classification strategy for early and accurate assessment of burn injuries using terahertz (THz) time-domain spectroscopic imaging. Burn injuries of different severity grades, representing superficial partial-thickness (SPT), deep partial-thickness (DPT), and full-thickness (FT) wounds, were created by a standardized porcine scald model. THz spectroscopic imaging was performed using our new fiber-coupled Portable HAndheld Spectral Reflection Scanner, incorporating a telecentric beam steering configuration and an f-\documentclass[12pt]{minimal}
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\begin{document}$$\theta$$\end{document}θ scanning lens. ASynchronous Optical Sampling in a dual-fiber-laser THz spectrometer with 100 MHz repetition rate enabled high-speed spectroscopic measurements. Given twenty-four different samples composed of ten scald and ten contact burns and four healthy samples, supervised machine learning algorithms using THz-TDS spectra achieved areas under the receiver operating characteristic curves of 0.88, 0.93, and 0.93 when differentiating between SPT, DPT, and FT burns, respectively, as determined by independent histological assessments. These results show the potential utility of our new broadband THz PHASR Scanner for early and accurate triage of burn injuries.
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12
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Leon UA, Rocco D, Carletti L, Peccianti M, Maci S, Della Valle G, De Angelis C. THz-photonics transceivers by all-dielectric phonon-polariton nonlinear nanoantennas. Sci Rep 2022; 12:4590. [PMID: 35301395 PMCID: PMC8931019 DOI: 10.1038/s41598-022-08695-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/08/2022] [Indexed: 11/09/2022] Open
Abstract
The THz spectrum (spanning from 0.3 to 30 THz) offers the potential of a plethora of applications, ranging from the imaging through non transparent media to wireless-over-fiber communications and THz-photonics. The latter framework would greatly benefit from the development of optical-to-THz wavelength converters. Exploiting Difference Frequency Generation in a nonlinear all dielectric nanoantenna, we propose a compact solution to this problem. By means of a near-infrared pump beam (at \documentclass[12pt]{minimal}
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\begin{document}$$\omega _1$$\end{document}ω1), the information signal in the optical domain (at \documentclass[12pt]{minimal}
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\begin{document}$$\omega _2$$\end{document}ω2) is converted to the THz band (at \documentclass[12pt]{minimal}
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\begin{document}$$\omega _3=\omega _2-\omega _1$$\end{document}ω3=ω2-ω1). The approach is completely transparent with respect to the modulation format, and can be easily integrated in a metasurface platform for simultaneous frequency and spatial moulding of THz beams.
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Affiliation(s)
- Unai Arregui Leon
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy
| | - Davide Rocco
- Department of Information Engineering, University of Brescia, via Branze 38, 25123, Brescia, Italy. .,National Institute of Optics, Consiglio Nazionale delle Ricerche, via Branze 45, 25123, Brescia, Italy.
| | - Luca Carletti
- Department of Information Engineering, University of Brescia, via Branze 38, 25123, Brescia, Italy.,National Institute of Optics, Consiglio Nazionale delle Ricerche, via Branze 45, 25123, Brescia, Italy
| | - Marco Peccianti
- Emergent Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton, BN1 9QH, UK
| | - Stefano Maci
- Department of Information Engineering and Mathematics, University of Siena, 53100, Siena, Italy
| | - Giuseppe Della Valle
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133, Milan, Italy.,Institute for Photonics and Nanotechnologies, Consiglio Nazionale delle Ricerche, Piazza Leonardo da Vinci 32, Milan, 20133, Italy
| | - Costantino De Angelis
- Department of Information Engineering, University of Brescia, via Branze 38, 25123, Brescia, Italy.,National Institute of Optics, Consiglio Nazionale delle Ricerche, via Branze 45, 25123, Brescia, Italy
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13
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Hu Y, Baggio M, Dabironezare S, Tamminen A, Toy B, Ala-Laurinaho J, Brown E, Llombart N, Deng SX, Wallace V, Taylor ZD. 650 GHz imaging as alignment verification for millimeter wave corneal reflectometry. IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY 2022; 12:151-164. [PMID: 36185397 PMCID: PMC9518788 DOI: 10.1109/tthz.2021.3140199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing 5 off-axis parabolic mirrors, a thin film beam splitter, and 2-axis galvanometric mirror was designed, simulated, and evaluated with geometric and physical optics. Simulation results informed the construction of a demonstrator system which was tested with a reference reflector. Similarity metrics computed with the aligned template and 26 misaligned positions, distributed on a 0.5 mm x 0.5 mm x 0.5 mm mesh, demonstrated sufficient misalignment detection sensitivity in 23 out of 26 positions. The results show that positional accuracy on the order of 0.5 mm is possible using 0.462 mm wavelength radiation due to the perturbation of coupling efficiency via beam distortion and beam walk-off.
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Affiliation(s)
- Yong Hu
- Department of Bioengineering, University of California, Los Angeles, CA 90095 USA
| | - Mariangela Baggio
- Department of Electronics and Nanoengineering, Aalto University, Espoo, FI-02150, Finland
| | - Shahab Dabironezare
- Center for Wireless Systems and Technology, Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Aleksi Tamminen
- Department of Electronics and Nanoengineering, Aalto University, Espoo, FI-02150, Finland
| | - Brandon Toy
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA 90095 USA
| | - Juha Ala-Laurinaho
- Department of Electronics and Nanoengineering, Aalto University, Espoo, FI-02150, Finland
| | - Elliott Brown
- College of Engineering and Computer Science, Wright State University, Dayton, OH, 45435, USA
| | - Nuria Llombart
- Center for Wireless Systems and Technology, Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Sophie X Deng
- Cornea Division, University of California, Los Angeles, 90095-1436, USA
| | - Vincent Wallace
- Department of Engineering and Mathematical Sciences, University of Western Australia, Crawley, WA, 6009, Australia
| | - Zachary D Taylor
- Department of Electronics and Nanoengineering, Aalto University, Espoo, FI-02150, Finland
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14
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Terahertz radiation in ophthalmology (review). ACTA BIOMEDICA SCIENTIFICA 2021. [DOI: 10.29413/abs.2021-6.6-1.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Terahertz (THz) radiation is one of the new, intensively studied interdisciplinary fi elds of scientifi c knowledge, including medicine, in the fi rst decades of the 21st century. At the beginning of this article (review), in a brief form, the basic statements on THz radiation, the main parameters and properties are presented; the modern THz biophtonics technologies used in biology and medicine are considered – THz refl ectometry, THz spectroscopy methods. Then a number of directions and examples of possible use of THz technologies in biology and medicine, including pharmaceuticals, are given. The main part of the review presents the progress of experimental research and the prospects for the clinical application of medical technologies of THz spectroscopy, THz imaging, in ophthalmology in the study of the morphological and functional state of the ocular surface structures, diagnosis, medical testing, and treatment of ophthalmopathology of the ocular surface. The article concludes with a review of experimental studies on the safety of using THz waves for medical diagnostics and treatment of ophthalmopathology. In the fi nal part, the main problems and prospects of introducing medical THz technologies into the clinical practice of an ophthalmologist are considered.
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15
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Frequency Division Multiplexing of Terahertz Waves Realized by Diffractive Optical Elements. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11146246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recently, one of the most commonly discussed applications of terahertz radiation is wireless telecommunication. It is believed that the future 6G systems will utilize this frequency range. Although the exact technology of future telecommunication systems is not yet known, it is certain that methods for increasing their bandwidth should be investigated in advance. In this paper, we present the diffractive optical elements for the frequency division multiplexing of terahertz waves. The structures have been designed as a combination of a binary phase grating and a converging diffractive lens. The grating allows for differentiating the frequencies, while the lens assures separation and focusing at the finite distance. Designed structures have been manufactured from polyamide PA12 using the SLS 3D printer and verified experimentally. Simulations and experimental results are shown for different focal lengths. Moreover, parallel data transmission is shown for two channels of different carrier frequencies propagating in the same optical path. The designed structure allowed for detecting both signals independently without observable crosstalk. The proposed diffractive elements can work in a wide range of terahertz and sub-terahertz frequencies, depending on the design assumptions. Therefore, they can be considered as an appealing solution, regardless of the band finally used by the future telecommunication systems.
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16
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Tanga AA, Giliberti V, Vitucci F, Vitulano D, Bruni V, Rossetti A, Messina GC, Daniele M, Ruocco G, Ortolani M. Terahertz scattering microscopy for dermatology diagnostics. JPHYS PHOTONICS 2021. [DOI: 10.1088/2515-7647/abfecb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
We explore the possibility of detecting anomalous structures buried under the skin surface by studying the deviations from the ideal Airy pattern of the point-spread function (PSF) of a terahertz microscope that includes the skin as one of the reflecting surfaces of the optical system. Using a custom terahertz microscope with a monochromatic point source emitting at 0.611 THz, we record the PSF images with a microbolometer camera. Skin simulants based on collagen gel, with and without artificial buried structures, have been analyzed. The geometrical features characterizing the PSF deformations have been extracted automatically from the PSF images. A machine learning algorithm applied to these geometrical features produces a reliable classification of targets with or without buried structures with error below 5%. It can even classify targets with anisotropic buried structures according to their different orientation.
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17
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Safonova TN, Fedorov AA, Surnina ZV, Sikach EI, Ozheredov IA. [Experimental investigation of the safety of terahertz radiation in corneal hydration assessment]. Vestn Oftalmol 2021; 137:58-67. [PMID: 34156779 DOI: 10.17116/oftalma202113703158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Application of terahertz (THz) radiation in novel non-invasive biomedical technologies has recently received considerable attention. However, experimental data about the safety of exposure to THz radiation for biological objects (including eye structures in vivo) are limited. To our knowledge, the safety of THz reflectometry (frequency range of 0.30-0.40 THz) has not been closely examined in an animal model with subsequent morphological assessment of corneal tissues. PURPOSE To assess the safety of pulsed THz radiation with various parameters (time, power, and frequency) for the cornea in a rabbit model. MATERIAL AND METHODS The sample for the current study consisted of 18 Chinchilla rabbits (18 eyes). Corneal imaging and epithelial cell density before and after the exposure were evaluated using confocal laser scanning microscopy (CLSM). The histological study for objective assessment of the cornea state (day 1 and day 14) was performed after experiment termination. RESULTS Single and multiple exposures of laser radiation at a frequency below 0.1 THz and power density below 30 nW/cm2 do not cause visible structural changes in any layers of the rabbit cornea. The results obtained in the long-term period showed insignificant reversible morphological changes only within the epithelium. CONCLUSION The described parameters of terahertz and subterahertz radiation can be considered safe for assessing changes in corneal epithelium hydration level using non-invasive methods based on THz reflectometry.
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Affiliation(s)
- T N Safonova
- Research Institute of Eye Diseases, Moscow, Russia
| | - A A Fedorov
- Research Institute of Eye Diseases, Moscow, Russia
| | - Z V Surnina
- Research Institute of Eye Diseases, Moscow, Russia
| | - E I Sikach
- Research Institute of Eye Diseases, Moscow, Russia
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18
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Chen A, Virk A, Harris Z, Abazari A, Honkanen R, Arbab MH. Non-contact terahertz spectroscopic measurement of the intraocular pressure through corneal hydration mapping. BIOMEDICAL OPTICS EXPRESS 2021; 12:3438-3449. [PMID: 34221670 PMCID: PMC8221940 DOI: 10.1364/boe.423741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 05/03/2023]
Abstract
Elevated intraocular pressure (IOP) results in endothelial layer damage that can induce corneal hydration perturbations. We investigated the potential of terahertz spectroscopy in measuring the IOP levels through mapping corneal water content. We controlled the IOP levels in ex vivo rabbit and porcine eye samples while monitoring the change in corneal hydration using a terahertz time-domain spectroscopy (THz-TDS) scanner. Our results showed a statistically significant increase in the THz reflectivity between 0.4 and 0.6 THz corresponding to the increase in the IOP. Endothelial layer damage was confirmed using scanning electron microscopy (SEM) of the corneal biopsy samples. Our empirical results indicate that the THz-TDS can be used to track IOP levels through the changes in corneal hydration.
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Affiliation(s)
- Andrew Chen
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Arjun Virk
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Zachery Harris
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Azin Abazari
- Department of Ophthalmology, Renaissance School of Medicine, 101 Nicolls Rd, Stony Brook, NY 11794, USA
| | - Robert Honkanen
- Department of Ophthalmology, Renaissance School of Medicine, 101 Nicolls Rd, Stony Brook, NY 11794, USA
| | - M. Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, 100 Nicolls Rd, Stony Brook, NY 11794, USA
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19
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Mizuno M, Kitahara H, Sasaki K, Tani M, Kojima M, Suzuki Y, Tasaki T, Tatematsu Y, Fukunari M, Wake K. Dielectric property measurements of corneal tissues for computational dosimetry of the eye in terahertz band in vivo and in vitro. BIOMEDICAL OPTICS EXPRESS 2021; 12:1295-1307. [PMID: 33796354 PMCID: PMC7984789 DOI: 10.1364/boe.412769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/16/2021] [Accepted: 01/27/2021] [Indexed: 05/08/2023]
Abstract
The dielectric constant of the normal corneal tissue of a rabbit eye was obtained in vitro in the range from approximately 0.1 to 1 THz, and the drying process on the eye surface exposed to high-power terahertz waves was investigated by in vivo reflectance measurement using terahertz time-domain spectroscopy. When the rabbit eye was exposed to terahertz waves at 162 GHz for 6 min with an irradiation power of 360 or 480 mW/cm2, the reflectance temporally increased and then decreased with a temperature increase. Based on multiple-reflection calculation using the dielectric constant and anterior segment optical coherence tomography images, those changes in reflectance were attributed to drying of the tear and epithelium of the cornea, respectively. Furthermore, the drying progressed over a temperature increase of around 5°C under our exposure conditions. These findings suggest that the possibility of eye damage increases with the progress of drying and that the setting of the eye surface conditions can be a cause of disagreement between computational and experimental data of absorbed energy under high-level irradiation because reflectance is related to terahertz wave penetration in the eye tissue. The time-domain spectroscopic measurements were useful for the acquisition of the dielectric constant as well as for the real-time monitoring of the eye conditions during exposure measurement.
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Affiliation(s)
- Maya Mizuno
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Hideaki Kitahara
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kensuke Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Masahiko Tani
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masami Kojima
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yukihisa Suzuki
- Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Takafumi Tasaki
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
- Department of Medical Zoology, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yoshinori Tatematsu
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masafumi Fukunari
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kanako Wake
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
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20
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Virk AS, Harris ZB, Arbab MH. Development of a terahertz time-domain scanner for topographic imaging of spherical targets. OPTICS LETTERS 2021; 46:1065-1068. [PMID: 33649658 PMCID: PMC10760507 DOI: 10.1364/ol.419140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 02/04/2021] [Indexed: 05/08/2023]
Abstract
Topographical abnormality in corneal tissue is a common diagnostic marker for many eye diseases and injuries. Using an asynchronous optical sampling terahertz time-domain spectroscopy setup, we developed a non-contact and normal-incidence imaging system to measure topographic changes along the surface of spherical samples. We obtained orthogonal 1D scans of calibration spheres to evaluate the minimum axial resolution of our system. We determined the axial and spatial resolution of the scanner using 3D-printed spherical cross and Boehler star targets. Furthermore, we characterized the asymmetrical performance of the scanner due to the use of an off-axis parabolic mirror. Finally, we developed an edge-detection filter to aid with improving the topographic scans. We showed that when imaging samples were comparable in size to the human cornea, the axial and spherical spatial resolutions were limited to about 15 µm (∼λ/67) and 1 mm, respectively.
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Affiliation(s)
- Arjun S. Virk
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
| | - Zachery B. Harris
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
| | - M. Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
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21
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Low cost and long-focal-depth metallic axicon for terahertz frequencies based on parallel-plate-waveguides. Sci Rep 2021; 11:3005. [PMID: 33542299 PMCID: PMC7862276 DOI: 10.1038/s41598-021-82503-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 01/18/2021] [Indexed: 11/09/2022] Open
Abstract
In this work we demonstrate a triangular surface lens (axicon) operating at frequencies between 350 and 450 GHz using parallel-plate-waveguide technology. The proposed axicon offers longer focal depth characteristics compared to conventional plastic lenses, surpassing common TPX lenses by one order of magnitude. Additionally, due to the triangular surface of the axicon, this device is able to focus THz radiation onto smaller areas than TPX lenses, enhancing the resolution characteristics of THz imaging systems. The frequency range of operation of the proposed axicon can be easily tuned by changing the space between plates, making this approach a very attractive candidate for low-cost, robust and easy to assemble solutions for the next generation of active THz devices.
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22
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Liu YC, Ke L, Yang SWQ, Nan Z, Teo EPW, Lwin NC, Lin MTY, Lee IXY, Chan ASY, Schmetterer L, Mehta JS. Safety profiles of terahertz scanning in ophthalmology. Sci Rep 2021; 11:2448. [PMID: 33510290 PMCID: PMC7843699 DOI: 10.1038/s41598-021-82103-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 01/15/2021] [Indexed: 01/20/2023] Open
Abstract
Terahertz (THz) technology has emerged recently as a potential novel imaging modality in biomedical fields, including ophthalmology. However, the ocular biological responses after THz electromagnetic exposure have not been investigated. We conducted a rabbit study to evaluate the safety profiles of THz scanning on eyes, at a tissue, cellular, structural and functional level. Eight animals (16 eyes) were analysed after excessive THz exposure (control, 1 h, 4 h, and 1 week after continuous 4-h exposure; THz frequency = 0.3 THz with continuous pulse generated at 40 µW). We found that at all the time points, the corneas and lens remained clear with no corneal haze or lens opacity formation clinically and histopathologically. No thermal effect, assessed by thermographer, was observed. The rod and cone cell-mediated electroretinography responses were not significantly altered, and the corneal keratocytes activity as well as endothelial viability, assessed by in-vivo confocal microscopy, was not affected. Post-exposed corneas, lens and retinas exhibited no significant changes in the mRNA expression of heat shock protein (HSP)90AB1), DNA damage inducible transcript 3 (DDIT3), and early growth response (EGR)1. These tissues were also negative for the inflammatory (CD11b), fibrotic (fibronectin and α-smooth muscle actin), stress (HSP-47) and apoptotic (TUNEL assay) responses on the immunohistochemical analyses. The optical transmittance of corneas did not change significantly, and the inter-fibrillar distances of the corneal stroma evaluated with transmission electron microscopy were not significantly altered after THz exposure. These results provide the basis for future research work on the development of THz imaging system for its application in ophthalmology.
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Affiliation(s)
- Yu-Chi Liu
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore. .,Singapore National Eye Centre, Singapore, Singapore. .,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore.
| | - Lin Ke
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Steve Wu Qing Yang
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Zhang Nan
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Ericia Pei Wen Teo
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Nyein Chan Lwin
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Molly Tzu-Yu Lin
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Isabelle Xin Yu Lee
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore
| | - Anita Sook-Yee Chan
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore.,School of Chemical and Biomedcial Engineering, Nanyang Technological University, Singapore, Singapore.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Jodhbir S Mehta
- Singapore Eye Research Institute, The Academia, 20 College Road, Discovery Tower, Level 12, Singapore, 169856, Singapore.,Singapore National Eye Centre, Singapore, Singapore.,Ophthalmology and Visual Science Academic Clinical Research Program, Duke-NUS Medical School, Singapore, Singapore
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23
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Yao J, Ma J, Zhao J, Qi P, Li M, Lin L, Sun L, Wang X, Liu W, Wang Y. Corneal hydration assessment indicator based on terahertz time domain spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:2073-2084. [PMID: 32341867 PMCID: PMC7173912 DOI: 10.1364/boe.387826] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/10/2020] [Accepted: 03/12/2020] [Indexed: 06/11/2023]
Abstract
Terahertz technology has shown broad prospects for measuring corneal water content, which is an important parameter of ocular health. Based on terahertz time-domain spectroscopy, a new indicator named characteristic ratio (CR) of the sum of low (0.2-0.7 THz) and high (0.7-1.0 THz) frequency spectral intensities, for characterizing corneal hydration is introduced in this work. CR is calculated from the real-time reflection spectra after error elimination of ex vivo human corneal stroma samples which is collected during dehydration under natural conditions (temperature: 22.4 ± 0.3°C; humidity: 20.0 ± 3%). The corresponding relationships between CR and corneal water content are reported. Comparing the linear fitting results with the published similar study, the coefficients of variation of the fitting slope and intercept are 39.4% and 27.6% lower, respectively. This indicates that this approach has the potential to achieve corneal water content in-vivo detection in the future.
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Affiliation(s)
- Jiali Yao
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Jiaonan Ma
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| | - Jiehui Zhao
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Pengfei Qi
- School of Physics, State Key Laboratory for Mesoscopic Physics, Academy for Advanced Interdisciplinary Studies, Collaborative Innovation Center of Quantum Matter, Nano-optoelectronics Frontier Center of Ministry of Education, Peking University, Beijing 100871, China
| | - Mengdi Li
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
| | - Lie Lin
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Lu Sun
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
- Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guangxi, China
| | - Xiaolei Wang
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Weiwei Liu
- Institute of Modern Optics, Nankai University, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China
| | - Yan Wang
- Tianjin Eye Hospital, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin 300020, China
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300070, China
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24
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Dong J, Breitenborn H, Piccoli R, Besteiro LV, You P, Caraffini D, Wang ZM, Govorov AO, Naccache R, Vetrone F, Razzari L, Morandotti R. Terahertz three-dimensional monitoring of nanoparticle-assisted laser tissue soldering. BIOMEDICAL OPTICS EXPRESS 2020; 11:2254-2267. [PMID: 32341881 PMCID: PMC7173899 DOI: 10.1364/boe.389561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 03/20/2020] [Accepted: 03/20/2020] [Indexed: 05/27/2023]
Abstract
In view of minimally-invasive clinical interventions, laser tissue soldering assisted by plasmonic nanoparticles is emerging as an appealing concept in surgical medicine, holding the promise of surgeries without sutures. Rigorous monitoring of the plasmonically-heated solder and the underlying tissue is crucial for optimizing the soldering bonding strength and minimizing the photothermal damage. To this end, we propose a non-invasive, non-contact, and non-ionizing modality for monitoring nanoparticle-assisted laser-tissue interaction and visualizing the localized photothermal damage, by taking advantage of the unique sensitivity of terahertz radiation to the hydration level of biological tissue. We demonstrate that terahertz radiation can be employed as a versatile tool to reveal the thermally-affected evolution in tissue, and to quantitatively characterize the photothermal damage induced by nanoparticle-assisted laser tissue soldering in three dimensions. Our approach can be easily extended and applied across a broad range of clinical applications involving laser-tissue interaction, such as laser ablation and photothermal therapies.
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Affiliation(s)
- Junliang Dong
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Holger Breitenborn
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Riccardo Piccoli
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Lucas V Besteiro
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, China
| | - Pei You
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Diego Caraffini
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Zhiming M Wang
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, China
| | - Alexander O Govorov
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, China
- Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA
| | - Rafik Naccache
- Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, Montreal, QC H4B 1R6, Canada
- Quebec Centre for Advanced Materials, Department of Chemistry and Biochemistry, Concordia University, Montreal, QC H4B 1R6, Canada
| | - Fiorenzo Vetrone
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Luca Razzari
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
| | - Roberto Morandotti
- Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications (EMT), Varennes, QC J3X 1S2, Canada
- Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan, China
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25
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Chen A, Osman OB, Harris ZB, Abazri A, Honkanen R, Arbab MH. Investigation of water diffusion dynamics in corneal phantoms using terahertz time-domain spectroscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:1284-1297. [PMID: 32206409 PMCID: PMC7075598 DOI: 10.1364/boe.382826] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 05/08/2023]
Abstract
Perturbation of normal corneal water content is a common manifestation of many eye diseases. Terahertz (THz) imaging has the potential to serve as a clinical tool for screening and diagnosing such corneal diseases. In this study, we first investigate the diffusive properties of a corneal phantom using simultaneous THz time-domain spectroscopy (THz-TDS) and gravimetric measurements. We will then utilize a variable-thickness diffusion model combined with a stratified composite-media model to simulate changes in thickness, hydration profile, and the THz-TDS signal as a function of time. The simulated THz-TDS signals show very good agreement with the reflection measurements. Results show that the THz-TDS technique can be used to understand water diffusion dynamics in corneal phantoms as a step towards future in vivo quantitative hydration sensing.
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Affiliation(s)
- Andrew Chen
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- Co-first authors with equal contribution
| | - Omar B. Osman
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
- Co-first authors with equal contribution
| | - Zachery B. Harris
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
| | - Azin Abazri
- Department of Ophthalmology, Stony Brook University, Stony Brook, NY 11794, USA
| | - Robert Honkanen
- Department of Ophthalmology, Stony Brook University, Stony Brook, NY 11794, USA
| | - M. Hassan Arbab
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA
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26
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Siemion A, Komorowski P, Surma M, Ducin I, Sobotka P, Walczakowski M, Czerwińska E. Terahertz diffractive structures for compact in-reflection inspection setup. OPTICS EXPRESS 2020; 28:715-723. [PMID: 32118994 DOI: 10.1364/oe.382272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/20/2019] [Indexed: 06/10/2023]
Abstract
Two diffractive optical elements are used to create a compact raster THz scanning setup in reflective configuration. The first one focuses the radiation into the small focal spot on the sample, while the second one collects reflected radiation and focuses it on the detector. To assure small size of the setup and large apertures of optical elements, structures work in the off-axis geometry. Thus, the focal spot is formed 100 mm after and 60 mm below the optical axis of the element, which measures 75 mm in diameter. The designed iterative algorithm allows further minimization of these values.
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27
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Wu L, Xu D, Wang Y, Liao B, Jiang Z, Zhao L, Sun Z, Wu N, Chen T, Feng H, Yao J. Study of in vivo brain glioma in a mouse model using continuous-wave terahertz reflection imaging. BIOMEDICAL OPTICS EXPRESS 2019; 10:3953-3962. [PMID: 31452987 PMCID: PMC6701535 DOI: 10.1364/boe.10.003953] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/29/2019] [Accepted: 06/29/2019] [Indexed: 05/21/2023]
Abstract
We demonstrated that in vivo brain glioma in a mouse model using a continuous-wave terahertz reflection imaging system, as well as the ex vivo fresh brain tissues in mouse model. The tumor regions of in vivo and ex vivo brain tissues can be well distinguished by THz intensity imaging at the frequency of 2.52THz. The THz images with high sensitivity correlated well with magnetic resonance, visual and hematoxylin and eosin stained images. Furthermore, the THz spectral difference between brain gliomas and normal brain tissues were obtained in the 0.6THz to 2.8THz range, where brain gliomas have the higher refractive indices and absorption coefficients, and their differences increase particularly in the high frequency range. These results suggest that THz imaging has great potential as an alternative method for the intraoperative label-free diagnosis of brain glioma in vivo.
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Affiliation(s)
- Limin Wu
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Degang Xu
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Yuye Wang
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Bin Liao
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Zhinan Jiang
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Lu Zhao
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Zhongcheng Sun
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
| | - Nan Wu
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Tunan Chen
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Hua Feng
- Department of Neurosurgery and Key Laboratory of Neurotrauma, Southwest Hospital, Third Military Medical University (Army Medical University), Chongqing 400038, China
| | - Jianquan Yao
- Institute of Laser and Optoelectronics, School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
- Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education), Tianjin University, Tianjin 300072, China
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28
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Liu YC, Ke L, Mehta JS. Evaluation of Corneal Oedema – Tools we Have and Those Under Investigation. ACTA ACUST UNITED AC 2019. [DOI: 10.17925/eor.2019.13.2.76] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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