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Zhu T, Zeng J, Wen F, Wang H. Determining the Dependence of Single Nitrogen-Vacancy Center Light Extraction in Diamond Nanostructures on Emitter Positions with Finite-Difference Time-Domain Simulations. Nanomaterials (Basel) 2023; 14:99. [PMID: 38202554 PMCID: PMC10780712 DOI: 10.3390/nano14010099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/26/2023] [Accepted: 12/29/2023] [Indexed: 01/12/2024]
Abstract
In this study, we obtained a diamond nanocone structure using the thermal annealing method, which was proposed in our previous work. Using finite-difference time-domain (FDTD) simulations, we demonstrate that the extraction efficiencies of nitrogen-vacancy (NV) center emitters in nanostructures are dependent on the geometries of the nanocone/nanopillar, emitter polarizations and axis depths. Our results show that nanocones and nanopillars have advantages in extraction from emitter dipoles with s- and p-polarizations, respectively. In our simulations, the best results of collection efficiency were achieved from the emitter in a nanocone with s-polarization (57.96%) and the emitter in a nanopillar with p-polarization (38.40%). Compared with the nanopillar, the photon extraction efficiency of the emitters in the nanocone is more sensitive to the depth and polarization angle. The coupling differences between emitters and the nanocone/nanopillar are explained by the evolution of photon propagation modes and the internal reflection effects in diamond nanostructures. Our results could have positive impacts on the design and fabrication of NV center-based micro- and nano-optics in the future.
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Affiliation(s)
- Tianfei Zhu
- Key Lab for Physical Electronics and Devices of the Ministry of Education, Faculty of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (J.Z.); (F.W.); (H.W.)
- Institute of Wide Bandgap Semiconductors, Xi’an Jiaotong University, Xi’an 710049, China
| | - Jia Zeng
- Key Lab for Physical Electronics and Devices of the Ministry of Education, Faculty of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (J.Z.); (F.W.); (H.W.)
- Institute of Wide Bandgap Semiconductors, Xi’an Jiaotong University, Xi’an 710049, China
| | - Feng Wen
- Key Lab for Physical Electronics and Devices of the Ministry of Education, Faculty of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (J.Z.); (F.W.); (H.W.)
- Institute of Wide Bandgap Semiconductors, Xi’an Jiaotong University, Xi’an 710049, China
| | - Hongxing Wang
- Key Lab for Physical Electronics and Devices of the Ministry of Education, Faculty of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China; (J.Z.); (F.W.); (H.W.)
- Institute of Wide Bandgap Semiconductors, Xi’an Jiaotong University, Xi’an 710049, China
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Shokova MA, Bochenkov VE. Impact of Optical Cavity on Refractive Index Sensitivity of Gold Nanohole Arrays. Biosensors (Basel) 2023; 13:1038. [PMID: 38131798 PMCID: PMC10741978 DOI: 10.3390/bios13121038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
Refractive index sensing based on surface plasmon resonance (SPR) is a highly efficient label-free technique for biomolecular detection. The performance of this method is defined by the dielectric properties of a sensing layer and its structure. Nanohole arrays in thin metal films provide good refractive index sensitivity but often suffer from a large resonance linewidth, which limits their broad practical application in biosensorics. Coupling the broad plasmon modes to sharp resonances can reduce the peak widths, but at the same time it can also degrade the sensitivity. Here, we use Finite-Difference Time Domain simulations to study the factors affecting the sensing performance of gold-silica-gold optical cavities with nanohole arrays in the dielectric and top metal layers. We demonstrate that by tuning resonator size and inter-hole spacing, the performance of the biosensor can be optimized and the figure of merit of the order of 5-7 is reached.
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Di Barba P, Januszkiewicz Ł, Kawecki J, Mognaschi ME. Electromagnetic Wave Absorption in the Human Head: A Virtual Sensor Based on a Deep-Learning Model. Sensors (Basel) 2023; 23:3131. [PMID: 36991842 PMCID: PMC10056223 DOI: 10.3390/s23063131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 06/19/2023]
Abstract
Determining the amount of electromagnetic wave energy absorbed by the human body is an important issue in the analysis of wireless systems. Typically, numerical methods based on Maxwell's equations and numerical models of the body are used for this purpose. This approach is time-consuming, especially in the case of high frequencies, for which a fine discretization of the model should be used. In this paper, the surrogate model of electromagnetic wave absorption in human body, utilizing Deep-Learning, is proposed. In particular, a family of data from finite-difference time-domain analyses makes it possible to train a Convolutional Neural Network (CNN), in view of recovering the average and maximum power density in the cross-section region of the human head at the frequency of 3.5 GHz. The developed method allows for quick determination of the average and maximum power density for the area of the entire head and eyeball areas. The results obtained in this way are similar to those obtained by the method based on Maxwell's equations.
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Affiliation(s)
- Paolo Di Barba
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100 Pavia, Italy
| | - Łukasz Januszkiewicz
- Institute of Electronics, Lodz University of Technology, Al. Politechniki 10, 93-590 Lodz, Poland
| | - Jarosław Kawecki
- Institute of Electronics, Lodz University of Technology, Al. Politechniki 10, 93-590 Lodz, Poland
| | - Maria Evelina Mognaschi
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 5, 27100 Pavia, Italy
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Abhijith T, E S, Suthar R, Sharma P, Thomas S, Karak S. Understanding the linear and nonlinear optical responses of few-layer exfoliated MoS 2and WS 2nanoflakes: experimental and simulation studies. Nanotechnology 2022; 33:435702. [PMID: 35850090 DOI: 10.1088/1361-6528/ac81d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Understanding the linear and nonlinear optical (NLO) responses of two-dimensional nanomaterials is essential to effectively utilize them in various optoelectronic applications. Here, few-layer MoS2and WS2nanoflakes with lateral size less than 200 nm were prepared by liquid-phase exfoliation, and their linear and NLO responses were studied simultaneously using experimental measurements and theoretical simulations. Finite-difference time-domain (FDTD) simulations confirmed the redshift in the excitonic transitions when the thickness was increased above 10 nm indicating the layer-number dependent bandgap of nanoflakes. WS2nanoflakes exhibited around 5 times higher absorption to scattering cross-section ratio than MoS2nanoflakes at various wavelengths. Open aperture Z scan analysis of both the MoS2and WS2nanoflakes using 532 nm nanosecond laser pulses reveals strong nonlinear absorption activity with effective nonlinear absorption coefficient (βeff) of 120 cm GW-1and 180 cm GW-1, respectively, which was attributed to the combined contributions of ground, singlet excited and triplet excited state absorption. FDTD simulation results also showed the signature of strong absorption density of few layer nanoflakes which may be account for their excellent NLO characteristics. Optical limiting threshold values of MoS2and WS2nanoflakes were obtained as ∼1.96 J cm-2and 0.88 J cm-2, respectively, which are better than many of the reported values. Intensity dependent switching from saturable absorption (SA) to reverse SA was also observed for MoS2nanoflakes when the laser intensity increased from 0.14 to 0.27 GW cm-2. The present study provides valuable information to improve the selection of two-dimensional nanomaterials for the design of highly efficient linear and nonlinear optoelectronic devices.
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Affiliation(s)
- T Abhijith
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Shiju E
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Rakesh Suthar
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Punit Sharma
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Sheenu Thomas
- International School of Photonics, Cochin University of Science and Technology, Cochin 682022, Kerala, India
| | - Supravat Karak
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India
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Ma X, Du B, Tan S, Song H, Liu S. Spectral Characteristics Simulation of Topological Micro-Nano Structures Based on Finite Difference Time Domain Method. Nanomaterials (Basel) 2021; 11:nano11102622. [PMID: 34685071 PMCID: PMC8539221 DOI: 10.3390/nano11102622] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/27/2021] [Accepted: 10/03/2021] [Indexed: 11/29/2022]
Abstract
Natural structural colors inspire people to obtain the technology of spectral characteristics by designing and preparing micro-nano structures on the material’s surface. In this paper, the finite difference time domain (FDTD) method is used to simulate the spectral selectivity of micro-nano grating on an Au surface, and the spectral response characteristics of different physical parameters to the incident light are obtained. The results show that, when the grating depth is shallow, the absorption peaks of TM polarized incident light on the material surface take on redshifts with the increase in the grating period. Meanwhile, when the depth-width ratio of the grating structure is high, the absorption peak appears in the reflection spectrum and presents a linear red shift with the increase in the grating period after the linearly polarized light TE wave incident on the surface of the micro-nano structure. At the same time, the wavelength of the absorption peak of the reflection spectrum and the grating period take on one-to-one correspondence relations, and when the TM polarized light is incident, the reflection spectrum exhibits obvious selective absorption characteristic peaks at certain grating periods (for example, when the period is 0.4 μm, there are three absorption peaks at the wavelengths of 0.7, 0.95, and 1.55 μm). These simulation results can provide a good theoretical basis for the preparation of micro-nano structures with spectral regulation function in the practical application.
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Affiliation(s)
- Xiaoran Ma
- Strong-Field and Ultrafast Photonics Lab, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; (X.M.); (B.D.); (S.T.)
- Key Laboratory of Trans-Scale Laser Manufacturing Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
| | - Bairui Du
- Strong-Field and Ultrafast Photonics Lab, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; (X.M.); (B.D.); (S.T.)
- Key Laboratory of Trans-Scale Laser Manufacturing Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
| | - Shengwang Tan
- Strong-Field and Ultrafast Photonics Lab, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; (X.M.); (B.D.); (S.T.)
- Key Laboratory of Trans-Scale Laser Manufacturing Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
| | - Haiying Song
- Strong-Field and Ultrafast Photonics Lab, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; (X.M.); (B.D.); (S.T.)
- Key Laboratory of Trans-Scale Laser Manufacturing Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
- Correspondence: (H.S.); (S.L.)
| | - Shibing Liu
- Strong-Field and Ultrafast Photonics Lab, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China; (X.M.); (B.D.); (S.T.)
- Key Laboratory of Trans-Scale Laser Manufacturing Technology, Ministry of Education, Beijing University of Technology, Beijing 100124, China
- Correspondence: (H.S.); (S.L.)
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Kisslinger R, Riddell S, Manuel AP, Alam KM, Kalra AP, Cui K, Shankar K. Nonlithographic Formation of Ta 2O 5 Nanodimple Arrays Using Electrochemical Anodization and Their Use in Plasmonic Photocatalysis for Enhancement of Local Field and Catalytic Activity. ACS Appl Mater Interfaces 2021; 13:4340-4351. [PMID: 33455157 DOI: 10.1021/acsami.0c18580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We demonstrate the formation of Ta2O5 nanodimple arrays on technologically relevant non-native substrates through a simple anodization and annealing process. The anodizing voltage determines the pore diameter (25-60 nm), pore depth (2-9 nm), and rate of anodization (1-2 nm/s of Ta consumed). The formation of Ta dimples after delamination of Ta2O5 nanotubes occurs within a range of voltages from 7 to 40 V. The conversion of dimples from Ta into Ta2O5 changes the morphology of the nanodimples but does not impact dimple ordering. Electron energy loss spectroscopy indicated an electronic band gap of 4.5 eV and a bulk plasmon band with a maximum of 21.5 eV. Gold nanoparticles (Au NPs) were coated on Ta2O5 nanodimple arrays by annealing sputtered Au thin films on Ta nanodimple arrays to simultaneously form Au NPs and convert Ta to Ta2O5. Au NPs produced this way showed a localized surface plasmon resonance maximum at 2.08 eV, red-shifted by ∼0.3 eV from the value in air or on SiO2 substrates. Lumerical simulations suggest a partial embedding of the Au NPs to explain this magnitude of the red shift. The resulting plasmonic heterojunctions exhibited a significantly higher ensemble-averaged local field enhancement than Au NPs on quartz substrates and demonstrated much higher catalytic activity for the plasmon-driven photo-oxidation of p-aminothiophenol to p,p'-dimercaptoazobenzene.
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Affiliation(s)
- Ryan Kisslinger
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Saralyn Riddell
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Ajay P Manuel
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Kazi M Alam
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
- Nanotechnology Research Centre, National Research Council of Canada, Edmonton, Alberta T6G 1H9, Canada
| | - Aarat P Kalra
- Department of Physics, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
| | - Kai Cui
- Nanotechnology Research Centre, National Research Council of Canada, Edmonton, Alberta T6G 1H9, Canada
| | - Karthik Shankar
- Department of Electrical and Computer Engineering, University of Alberta, 9211-116 Street, Edmonton, Alberta T6G 1H9, Canada
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7
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Shen T, Tan Q, Dai Z, Padture NP, Pacifici D. Arrays of Plasmonic Nanostructures for Absorption Enhancement in Perovskite Thin Films. Nanomaterials (Basel) 2020; 10:nano10071342. [PMID: 32660111 PMCID: PMC7408564 DOI: 10.3390/nano10071342] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 11/16/2022]
Abstract
We report optical characterization and theoretical simulation of plasmon enhanced methylammonium lead iodide (MAPbI 3 ) thin-film perovskite solar cells. Specifically, various nanohole (NH) and nanodisk (ND) arrays are fabricated on gold/MAPbI 3 interfaces. Significant absorption enhancement is observed experimentally in 75 nm and 110 nm-thick perovskite films. As a result of increased light scattering by plasmonic concentrators, the original Fabry-Pérot thin-film cavity effects are suppressed in specific structures. However, thanks to field enhancement caused by plasmonic resonances and in-plane interference of propagating surface plasmon polaritons, the calculated overall power conversion efficiency (PCE) of the solar cell is expected to increase by up to 45.5%, compared to its flat counterpart. The role of different geometry parameters of the nanostructure arrays is further investigated using three dimensional (3D) finite-difference time-domain (FDTD) simulations, which makes it possible to identify the physical origin of the absorption enhancement as a function of wavelength and design parameters. These findings demonstrate the potential of plasmonic nanostructures in further enhancing the performance of photovoltaic devices based on thin-film perovskites.
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Lafuente M, Berenschot EJW, Tiggelaar RM, Rodrigo SG, Mallada R, Tas NR, Pina MP. Attomolar SERS detection of organophosphorous pesticides using silver mirror-like micro-pyramids as active substrate. Mikrochim Acta 2020; 187:247. [PMID: 32219540 DOI: 10.1007/s00604-020-4216-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/05/2020] [Indexed: 01/03/2023]
Abstract
Surface-enhanced Raman spectroscopy (SERS) is gaining importance as an ultrasensitive analytical tool for routine high-throughput analysis of a variety of molecular compounds. One of the main challenges is the development of robust, reproducible and cost-effective SERS substrates. In this work, we study the SERS activity of 3D silver mirror-like micro-pyramid structures extended in the z-direction up to 3.7 μm (G0 type substrate) or 7.7 μm (G1 type substrate), prepared by Si-based microfabrication technologies, for trace detection of organophosphorous pesticides, using paraoxon-methyl as probe molecule. The average relative standard deviation (RSD) for the SERS intensity of the peak displayed at 1338 cm-1 recorded over a centimetre scale area of the substrate is below 13% for pesticide concentrations in the range 10-6 to 10-15 mol L-1. This data underlies the spatial uniformity of the SERS response provided by the microfabrication approach. According to finite-difference time-domain (FDTD) simulations, such remarkable feature is mainly due to the contribution on electromagnetic field enhancement of edge plasmon polaritons (EPPs), propagating along the pyramid edges where the pesticide molecules are preferentially adsorbed. Graphical abstract.
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Balestri D, Petruzzella M, Checcucci S, Intonti F, Caselli N, Sgrignuoli F, van Otten FWM, Fiore A, Gurioli M. Mechanical and Electric Control of Photonic Modes in Random Dielectrics. Adv Mater 2019; 31:e1807274. [PMID: 30714221 DOI: 10.1002/adma.201807274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/26/2018] [Indexed: 06/09/2023]
Abstract
Random dielectrics defines a class of non-absorbing materials where the index of refraction is randomly arranged in space. Whenever the transport mean free path is sufficiently small, light can be confined in modes with very small volume. Random photonic modes have been investigated for their basic physical insights, such as Anderson localization, and recently several applications have been envisioned in the field of renewable energies, telecommunications, and quantum electrodynamics. An advantage for optoelectronics and quantum source integration offered by random systems is their high density of photonic modes, which span a large range of spectral resonances and spatial distributions, thus increasing the probability to match randomly distributed emitters. Conversely, the main disadvantage is the lack of deterministic engineering of one or more of the many random photonic modes achieved. This issue is solved by demonstrating the capability to electrically and mechanically control the random modes at telecom wavelengths in a 2D double membrane system. Very large and reversible mode tuning (up to 50 nm), both toward shorter or longer wavelength, is obtained for random modes with modal volumes of the order of few tens of (λ/n)3 .
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Affiliation(s)
- Dario Balestri
- Department of Physics and Astronomy and LENS, University of Florence, via Sansone 1, I-50019, Sesto Fiorentino (FI), Italy
| | - Maurangelo Petruzzella
- Department of Applied Physics and Institute for Photonic Integration, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Simona Checcucci
- Department of Physics and Astronomy and LENS, University of Florence, via Sansone 1, I-50019, Sesto Fiorentino (FI), Italy
| | - Francesca Intonti
- Department of Physics and Astronomy and LENS, University of Florence, via Sansone 1, I-50019, Sesto Fiorentino (FI), Italy
| | - Niccolò Caselli
- Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientìficas, c/Sor Juana Inés de la Cruz 3, 28049, Madrid, Spain
| | - Fabrizio Sgrignuoli
- Department. of Electrical and Computer Engineering, Boston University, Boston, MA, 02215, USA
| | - Frank W M van Otten
- Department of Applied Physics and Institute for Photonic Integration, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Andrea Fiore
- Department of Applied Physics and Institute for Photonic Integration, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Massimo Gurioli
- Centre National de la Recherche Scientifique, Aix-Marseille Université, Centrale Marseille UMR 7334, Campus de St. Jérôme, 13397, Marseille, France
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Chiappini A, Pasquardini L, Nodehi S, Armellini C, Bazzanella N, Lunelli L, Pelli S, Ferrari M, Pietralunga SM. Fluorescent Aptamer Immobilization on Inverse Colloidal Crystals. Sensors (Basel) 2018; 18:E4326. [PMID: 30544583 DOI: 10.3390/s18124326] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/03/2018] [Accepted: 12/04/2018] [Indexed: 02/06/2023]
Abstract
In this paper, we described a versatile two steps approach for the realization of silica inverse opals functionalized with DNA-aptamers labelled with Cy3 fluorophore. The co-assembly method was successfully employed for the realization of high quality inverse silica opal, whilst the inverse network was functionalized via epoxy chemistry. Morphological and optical assessment revealed the presence of large ordered domains with a transmission band gap depth of 32%, after the functionalization procedure. Finite Difference Time-Domain (FDTD) simulations confirmed the high optical quality of the inverse opal realized. Photoluminescence measurements evidenced the effective immobilization of DNA-aptamer molecules labelled with Cy3 throughout the entire sample thickness. This assumption was verified by the inhibition of the fluorescence of Cy3 fluorophore tailoring the position of the photonic band gap of the inverse opal. The modification of the fluorescence could be justified by a variation in the density of states (DOS) calculated by the Plane Wave Expansion (PWE) method. Finally, the development of the aforementioned approach could be seen as proof of the concept experiment, suggesting that this type of system may act as a suitable platform for the realization of fluorescence-based bio-sensors.
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Nair AT, Palappra SP, Reddy VS. Influence of Ag Nanostructure Location on the Absorption Enhancement in Polymer Solar Cells. ACS Appl Mater Interfaces 2018; 10:32483-32491. [PMID: 30168314 DOI: 10.1021/acsami.8b13560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The optical absorption enhancement in Ag nanocube (NC)- and nanosphere (NS)-embedded poly[ N-9'-heptadecanyl-2,7-carbazole- alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]:[6,6]-phenyl C71-butyric acid methyl ester active layer was calculated using three-dimensional finite-difference time domain simulations. The simulations were carried out by incorporating Ag nanostructures as a two-dimensional array at various locations in the active layer matrix. High absorption enhancements of 53 and 61% were achieved with NSs and NCs, respectively, when they were incorporated at the top portion of the active layer. The influence of various passivation layers on the absorption enhancement was also investigated. The simulation results revealed that the absorption enhancement is mainly due to the near-field enhancement around the nanostructures and the backward reflection of incident light from the nanostructure array.
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Affiliation(s)
- Abhijith T Nair
- Organic and Nanoelectronics Laboratory, Department of Physics , National Institute of Technology Calicut (NITC) , Calicut 673 601 , Kerala , India
| | - Shamjid P Palappra
- Organic and Nanoelectronics Laboratory, Department of Physics , National Institute of Technology Calicut (NITC) , Calicut 673 601 , Kerala , India
| | - V S Reddy
- Organic and Nanoelectronics Laboratory, Department of Physics , National Institute of Technology Calicut (NITC) , Calicut 673 601 , Kerala , India
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12
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Boiko VV, Romanyuk VR, Gnatyuk OP, Ilchenko OO, Karakhim SO, Korovin AV, Dovbeshko GI. Vibrational spectra of DNA in the confined interglobular volume of photonic crystal. J Biol Phys 2018; 44:101-116. [PMID: 29464434 PMCID: PMC5835003 DOI: 10.1007/s10867-018-9480-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 01/03/2018] [Indexed: 11/26/2022] Open
Abstract
The impact of confinement of DNA molecules in a limited volume of the cavity of photonic crystals (PC) on the vibrational properties of the DNA molecule and its conformation is studied. According to our preliminary study, the aqueous shell is removed when the DNA molecules are infiltrated into the PC cavities. Raman scattering (RS) DNA marker lines showed a dramatic conformational change of DNA in the PC cavities and the appearance of new unknown conformational states. We observed the enhancement of vibrational modes of DNA in the PC in comparison with free DNA of about tenfold and the absence of vibrational modes in DNA bases in a region of 1450-1700 cm-1. The observed features in the RS spectra of DNA are explained by the impact of confined interglobular volume and strong localization of the electromagnetic field. Namely, FDTD simulations in linear regime demonstrate the localization of light in cavities of PC with an approximately ninefold enhancement of the electric field within the photonic stop-band, which is the main reason for RS amplification.
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Affiliation(s)
- V V Boiko
- Department of Physics of Biological Systems, Institute of Physics, NAS of Ukraine, Prospect Nauki, 46, Kyiv, 03680, Ukraine.
| | - V R Romanyuk
- Department of Polaritonic Optoelectronics, Institute for Physics of Semiconductors, NAS of Ukraine, Prospect Nauki, 41, Kyiv, 03028, Ukraine
| | - O P Gnatyuk
- Department of Physics of Biological Systems, Institute of Physics, NAS of Ukraine, Prospect Nauki, 46, Kyiv, 03680, Ukraine
| | - O O Ilchenko
- Department of Epigenetics, D.F. Chebotarev State Institute of Gerontology, NAMS of Ukraine, Vyshhorodska Str, 67, Kyiv, 04114, Ukraine
| | - S O Karakhim
- Department of Muscle Biochemistry, Palladin Institute of Biochemistry, NAS of Ukraine, Leontovicha Str. 9, Kyiv, 01601, Ukraine
| | - A V Korovin
- Department of Polaritonic Optoelectronics, Institute for Physics of Semiconductors, NAS of Ukraine, Prospect Nauki, 41, Kyiv, 03028, Ukraine
| | - G I Dovbeshko
- Department of Physics of Biological Systems, Institute of Physics, NAS of Ukraine, Prospect Nauki, 46, Kyiv, 03680, Ukraine
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Abstract
An extension of the Maxwell-Faraday law of electromagnetic induction to optical frequencies requires spatially appropriate materials and optical beams to create resonances and excitations with curl. Here we employ cylindrical vector beams with azimuthal polarization to create electric fields that selectively drive magnetic responses in dielectric core-metal nanoparticle "satellite" nanostructures. These optical frequency magnetic resonances are induced in materials that do not possess spin or orbital angular momentum. Multipole expansion analysis of the scattered fields obtained from electrodynamics simulations show that the excitation with azimuthally polarized beams selectively enhances magnetic vs electric dipole resonances by nearly 100-fold in experiments. Multipolar resonances (e.g., quadrupole and octupole) are enhanced 5-fold by focused azimuthally versus linearly polarized beams. We also selectively excite electric multipolar resonances in the same identical nanostructures with radially polarized light. This work opens new opportunities for spectroscopic investigation and control of "dark modes", Fano resonances, and magnetic modes in nanomaterials and engineered metamaterials.
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Affiliation(s)
- Uttam Manna
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - Jung-Hoon Lee
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - Tian-Song Deng
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - John Parker
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - Nolan Shepherd
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - Yossi Weizmann
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
| | - Norbert F Scherer
- The James Franck Institute, ‡Department of Chemistry, §Department of Physics, University of Chicago , Chicago, Illinois 60637, United States
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14
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Wilczek A, Szypłowska A, Kafarski M, Skierucha W. A Time-Domain Reflectometry Method with Variable Needle Pulse Width for Measuring the Dielectric Properties of Materials. Sensors (Basel) 2016; 16:191. [PMID: 26861318 DOI: 10.3390/s16020191] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 01/20/2016] [Accepted: 01/29/2016] [Indexed: 11/16/2022]
Abstract
Time-domain reflectometry (TDR) methods used for measuring the dielectric properties of materials mostly utilize step or needle electrical pulses of constant amplitudes and shapes. Our novel approach enables determining the dielectric relaxation time of a sample using the analysis of the amplitudes of reflected pulses of two widths, in addition to bulk dielectric permittivity and electrical conductivity commonly obtained by the TDR technique. The method was developed for various values of electrical conductivity and relaxation time using numerical simulations of a five-rod probe placed in a material with complex dielectric permittivity described by the Debye model with an added electrical conductivity term. The characterization of amplitudes of two pulses of selected widths was done with regard to the dielectric parameters of simulated materials. The required probe parameters were obtained solely from numerical simulations. Verification was performed for the probe placed in aqueous KCl solutions with 14 different electrical conductivity values. The determined relaxation time remained roughly constant and independent of electrical conductivity. The obtained electrical conductivity agreed with the reference values. Our results indicate that the relaxation time, dielectric permittivity and electrical conductivity of the tested solutions can be simultaneously determined using a simple analysis of the amplitude and reflection time of two needle pulses of different widths.
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15
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Peralta L, Rus G, Bochud N, Molina FS. Mechanical assessment of cervical remodelling in pregnancy: insight from a synthetic model. J Biomech 2015; 48:1557-65. [PMID: 25766389 DOI: 10.1016/j.jbiomech.2015.02.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 02/15/2015] [Indexed: 11/16/2022]
Abstract
During the gestation and the cervical remodelling, several changes occur progressively in the structure of the tissue. An increase in the hydration, disorganisation of collagen network and decrease in elasticity can be observed. The collagen structure disorganisation is particularly complex: collagen fibres turn thicker and more wavy as the gestation progresses in a transition from relatively straight fibres to wavy fibres, while pores between collagen fibres become larger and separated. Shear wave elastography is a promising but not yet fully understood tool to assess these structural changes and the cervix׳s ability to dilate. To this end, a numerical histo-mechanical model is proposed in the present study, which aims at linking variations in the microscopic histo-biomechanical processes with shear wave propagation characteristics. Parametric simulations are carried out for a broad range of mechanical and geometrical parameters. Results show a direct relationship between the histological and morphological changes during pregnancy and the viscoelastic behaviour of the tissue.
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Affiliation(s)
- L Peralta
- Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071 Granada, Spain.
| | - G Rus
- Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071 Granada, Spain
| | - N Bochud
- Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071 Granada, Spain
| | - F S Molina
- Maternal-Fetal Medicine Unit, Department of Obstetrics and Gynecology, San Cecilio University Hospital (HUSC), Granada, Spain
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16
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Dickreuter S, Gleixner J, Kolloch A, Boneberg J, Scheer E, Leiderer P. Mapping of plasmonic resonances in nanotriangles. Beilstein J Nanotechnol 2013; 4:588-602. [PMID: 24205453 PMCID: PMC3817793 DOI: 10.3762/bjnano.4.66] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/11/2013] [Indexed: 05/21/2023]
Abstract
Plasmonic resonances in metallic nano-triangles have been investigated by irradiating these structures with short laser pulses and imaging the resulting ablation and melting patterns. The triangular gold structures were prepared on Si substrates and had a thickness of 40 nm and a side length of ca. 500 nm. Irradiation was carried out with single femtosecond and picosecond laser pulses at a wavelength of 800 nm, which excited higher order plasmon modes in these triangles. The ablation distribution as well as the local melting of small parts of the nanostructures reflect the regions of large near-field enhancement. The observed patterns are reproduced in great detail by FDTD simulations with a 3-dimensional model, provided that the calculations are not based on idealized, but on realistic structures. In this realistic model, details like the exact shape of the triangle edges and the dielectric environment of the structures are taken into account. The experimental numbers found for the field enhancement are typically somewhat smaller than the calculated ones. The results demonstrate the caveats for FDTD simulations and the potential and the limitations of "near field photography" by local ablation and melting for the mapping of complex plasmon fields and their applications.
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Affiliation(s)
- Simon Dickreuter
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Julia Gleixner
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Andreas Kolloch
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Johannes Boneberg
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Elke Scheer
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
| | - Paul Leiderer
- Physics Department, University of Konstanz, Universitätsstraße 10, 78464 Konstanz, Germany
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