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Kumari P, Basnet B, Wang H, Lavrentovich OD. Ferroelectric nematic liquids with conics. Nat Commun 2023; 14:748. [PMID: 36765061 PMCID: PMC9918734 DOI: 10.1038/s41467-023-36326-1] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 01/23/2023] [Indexed: 02/12/2023] Open
Abstract
Spontaneous electric polarization of solid ferroelectrics follows aligning directions of crystallographic axes. Domains of differently oriented polarization are separated by domain walls (DWs), which are predominantly flat and run along directions dictated by the bulk translational order and the sample surfaces. Here we explore DWs in a ferroelectric nematic (NF) liquid crystal, which is a fluid with polar long-range orientational order but no crystallographic axes nor facets. We demonstrate that DWs in the absence of bulk and surface aligning axes are shaped as conic sections. The conics bisect the angle between two neighboring polarization fields to avoid electric charges. The remarkable bisecting properties of conic sections, known for millennia, play a central role as intrinsic features of liquid ferroelectrics. The findings could be helpful in designing patterns of electric polarization and space charge.
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Affiliation(s)
- Priyanka Kumari
- grid.258518.30000 0001 0656 9343Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242 USA ,grid.258518.30000 0001 0656 9343Materials Science Graduate Program, Kent State University, Kent, OH 44242 USA
| | - Bijaya Basnet
- grid.258518.30000 0001 0656 9343Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242 USA ,grid.258518.30000 0001 0656 9343Materials Science Graduate Program, Kent State University, Kent, OH 44242 USA
| | - Hao Wang
- grid.258518.30000 0001 0656 9343Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242 USA
| | - Oleg D. Lavrentovich
- grid.258518.30000 0001 0656 9343Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242 USA ,grid.258518.30000 0001 0656 9343Materials Science Graduate Program, Kent State University, Kent, OH 44242 USA ,grid.258518.30000 0001 0656 9343Department of Physics, Kent State University, Kent, OH 44242 USA
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2
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Chan MC, Liao TH, Hsieh CS, Jeng SC, Zhuo GY. Imaging of nanoscale birefringence using polarization-resolved chromatic confocal microscopy. Opt Express 2021; 29:3965-3975. [PMID: 33770985 DOI: 10.1364/oe.414511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
We demonstrate a homebuilt confocal microscope with ∼60 nm axial resolution to visualize the optical path length (OPL) of liquid crystals (LCs) inside a 2-domain alignment LC cell. Since the microscope is sensitive to light polarization, it is capable of determining LC orientation by accounting for the OPL variation, ΔOPL. The resolution of birefringence depends on the measured ΔOPL from two cross-polarized channel detections, of which the concept is different from other polarization-resolved optical imaging techniques, but is relatively simple in optical layout and analysis. The different orientations of LCs and the voltage-dependent LC rotation properties in the 2-domain LC cell are monitored and analyzed. Additionally, the complicated LC orientation distribution at the junction of the two domains with different alignments can be clearly observed. It shows great possibilities of examining tissue birefringence related to disease progression and tiny birefringence variation of electro-optical materials under an external field, which are hardly resolved by conventional optical imaging techniques.
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Lee YJ. Theory of birefringence correction for polarization-controlled CARS. Opt Express 2020; 28:9158-9173. [PMID: 32225528 PMCID: PMC7417012 DOI: 10.1364/oe.389558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 03/05/2020] [Indexed: 06/10/2023]
Abstract
Polarization-controlled coherent Raman spectroscopy is used as a high-throughput method to characterize the anisotropic nature of a molecular system, such as the molecular orientation distribution. However, optical birefringence originating from the molecular anisotropy can cause the observed Raman spectrum to be significantly distorted, making it extremely challenging to obtain quantitative information from polarization Raman measurements. Here, the birefringence effect on the signal intensity and the spectral shape of a polarization-controlled coherent anti-Stokes Raman scattering (CARS) is theoretically described using a uniaxially symmetrical model system. Due to the complexity, the effect of phase delay in the incident lights is not considered but only that of the generated CARS signal is considered. A new analytical method is presented to eliminate the birefringence contribution from polarization-controlled CARS data by analyzing polarization intensity profiles and retrieving the resonant Raman susceptibility spectra. This method is tested with two sets of polarization-controlled CARS data simulated with various combinations of symmetries of multiple underlying Raman modes. The analysis result clearly demonstrates that the effect of birefringence can be corrected for polarization-controlled CARS data and the symmetry tensor elements of all underlying Raman modes can be quantitatively characterized.
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Affiliation(s)
- Young Jong Lee
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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4
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Jones RR, Hooper DC, Zhang L, Wolverson D, Valev VK. Raman Techniques: Fundamentals and Frontiers. Nanoscale Res Lett 2019; 14:231. [PMID: 31300945 PMCID: PMC6626094 DOI: 10.1186/s11671-019-3039-2] [Citation(s) in RCA: 203] [Impact Index Per Article: 40.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 06/03/2019] [Indexed: 05/19/2023]
Abstract
Driven by applications in chemical sensing, biological imaging and material characterisation, Raman spectroscopies are attracting growing interest from a variety of scientific disciplines. The Raman effect originates from the inelastic scattering of light, and it can directly probe vibration/rotational-vibration states in molecules and materials. Despite numerous advantages over infrared spectroscopy, spontaneous Raman scattering is very weak, and consequently, a variety of enhanced Raman spectroscopic techniques have emerged. These techniques include stimulated Raman scattering and coherent anti-Stokes Raman scattering, as well as surface- and tip-enhanced Raman scattering spectroscopies. The present review provides the reader with an understanding of the fundamental physics that govern the Raman effect and its advantages, limitations and applications. The review also highlights the key experimental considerations for implementing the main experimental Raman spectroscopic techniques. The relevant data analysis methods and some of the most recent advances related to the Raman effect are finally presented. This review constitutes a practical introduction to the science of Raman spectroscopy; it also highlights recent and promising directions of future research developments.
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Affiliation(s)
- Robin R. Jones
- Turbomachinery Research Centre, University of Bath, Bath, BA2 7AY UK
| | - David C. Hooper
- Centre for Photonics and Photonic Materials, University of Bath, Bath, BA2 7AY UK
- Centre for Nanoscience and Nanotechnology, University of Bath, Bath, BA2 7AY UK
| | - Liwu Zhang
- Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433 China
| | - Daniel Wolverson
- Centre for Photonics and Photonic Materials, University of Bath, Bath, BA2 7AY UK
- Centre for Nanoscience and Nanotechnology, University of Bath, Bath, BA2 7AY UK
| | - Ventsislav K. Valev
- Centre for Photonics and Photonic Materials, University of Bath, Bath, BA2 7AY UK
- Centre for Nanoscience and Nanotechnology, University of Bath, Bath, BA2 7AY UK
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5
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Turcotte R, Rutledge DJ, Bélanger E, Dill D, Macklin WB, Côté DC. Intravital assessment of myelin molecular order with polarimetric multiphoton microscopy. Sci Rep 2016; 6:31685. [PMID: 27538357 PMCID: PMC4990840 DOI: 10.1038/srep31685] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/25/2016] [Indexed: 11/22/2022] Open
Abstract
Myelin plays an essential role in the nervous system and its disruption in diseases such as multiple sclerosis may lead to neuronal death, thus causing irreversible functional impairments. Understanding myelin biology is therefore of fundamental and clinical importance, but no tools currently exist to describe the fine spatial organization of myelin sheaths in vivo. Here we demonstrate intravital quantification of the myelin molecular structure using a microscopy method based on polarization-resolved coherent Raman scattering. Developmental myelination was imaged noninvasively in live zebrafish. Longitudinal imaging of individual axons revealed changes in myelin organization beyond the diffraction limit. Applied to promyelination drug screening, the method uniquely enabled the identification of focal myelin regions with differential architectures. These observations indicate that the study of myelin biology and the identification of therapeutic compounds will largely benefit from a method to quantify the myelin molecular organization in vivo.
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Affiliation(s)
- Raphaël Turcotte
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval, Québec, QC G1J 2G3, Canada
| | - Danette J Rutledge
- Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Erik Bélanger
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval, Québec, QC G1J 2G3, Canada
| | - Dorothy Dill
- Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Wendy B Macklin
- Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Daniel C Côté
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Québec, Université Laval, Québec, QC G1J 2G3, Canada.,Centre d'Optique, Photonique et Laser, Université Laval, Québec, QC G1V 0A6, Canada
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6
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Teulon C, Tidu A, Portier F, Mosser G, Schanne-Klein MC. Probing the 3D structure of cornea-like collagen liquid crystals with polarization-resolved SHG microscopy. Opt Express 2016; 24:16084-98. [PMID: 27410876 DOI: 10.1364/oe.24.016084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
This work aims at characterizing the three-dimensional organization of liquid crystals composed of collagen, in order to determine the physico-chemical conditions leading to highly organized structures found in biological tissues such as cornea. To that end, we use second-harmonic generation (SHG) microscopy, since aligned collagen structures have been shown to exhibit intrinsic SHG signals. We combine polarization-resolved SHG experiments (P-SHG) with the theoretical derivation of the SHG signal of collagen molecules tilted with respect to the focal plane. Our P-SHG images exhibit striated patterns with variable contrast, as expected from our analytical and numerical calculations for plywood-like nematic structures similar to the ones found in the cornea. This study demonstrates the benefits of P-SHG microscopy for in situ characterization of highly organized biopolymers at micrometer scale, and the unique sensitivity of this nonlinear optical technique to the orientation of collagen molecules.
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Cacace T, García-García A, Zito G, Tkachenko V, Rusciano G, Geday MA, Otón JM, Marino A, Sasso A. Nematic liquid crystal reorientation around multi-walled carbon nanotubes mapped via Raman microscopy. Opt Express 2016; 24:15954-15964. [PMID: 27410863 DOI: 10.1364/oe.24.015954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have studied the formation of topological defects in liquid crystal (LC) matrices induced by multiwalled carbon nanotubes (MWCNTs) and external electric fields. The defects are ascribable to a distortion of the LC molecular director in proximity of the MWCNT surface. The system is analyzed macroscopically using spectroscopic variable angle ellipsometry. Concurrently, confocal micro-Raman spectroscopy is used to study the system state at the microscale. This allows to acquire a three-dimensional, spatially-resolved map of the topological defect, determining scale length variations and orientation topography of the LC molecules around the MWCNT.
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8
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Lee YJ. Determination of 3D molecular orientation by concurrent polarization analysis of multiple Raman modes in broadband CARS spectroscopy. Opt Express 2015; 23:29279-95. [PMID: 26561197 PMCID: PMC4819338 DOI: 10.1364/oe.23.029279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A theoretical description is presented about a new analysis method to determine three-dimensional (3D) molecular orientation by concurrently analyzing multiple Raman polarization profiles. Conventional approaches to polarization Raman spectroscopy are based on single peaks, and their 2D-projected polarization profiles are limited in providing 3D orientational information. Our new method analyzes multiple Raman profiles acquired by a single polarization scanning measurement of broadband coherent anti-Stokes Raman scattering (BCARS). Because the analysis uses only dimensionless quantities, such as intensity ratios and phase difference between multiple profiles, the results are not affected by sample concentration and the system response function. We describe how to determine the 3D molecular orientation with the dimensionless observables by using two simplified model cases. In addition, we discuss the effect of orientational broadening on the polarization profiles in the two model cases. We find that in the presence of broadening we can still determine the mean 3D orientation angles and, furthermore, the degree of orientational broadening.
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Affiliation(s)
- Young Jong Lee
- Biosystems and Biomaterials Division, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, MD 20899, USA
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10
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Kim Y, Jeong J, Jang J, Kim MW, Park Y. Polarization holographic microscopy for extracting spatio-temporally resolved Jones matrix. Opt Express 2012; 20:9948-55. [PMID: 22535087 DOI: 10.1364/oe.20.009948] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We present a high-speed holographic microscopic technique for quantitative measurement of polarization light-field, referred to as polarization holographic microscopy (PHM). Employing the principle of common-path interferometry, PHM quantitatively measures the spatially resolved Jones matrix components of anisotropic samples with only two consecutive measurements of spatially modulated holograms. We demonstrate the features of PHM with imaging the dynamics of liquid crystal droplets at a video-rate.
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Affiliation(s)
- Youngchan Kim
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701, South Korea
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11
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Choudhury TD, Rao NVS, Tenent R, Blackburn J, Gregg B, Smalyukh II. Homeotropic Alignment and Director Structures in Thin Films of Triphenylamine-Based Discotic Liquid Crystals Controlled by Supporting Nanostructured Substrates and Surface Confinement. J Phys Chem B 2011; 115:609-17. [DOI: 10.1021/jp106344f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Trirup Dutta Choudhury
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Nandiraju V. S. Rao
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Robert Tenent
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Jeffrey Blackburn
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Brian Gregg
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
| | - Ivan I. Smalyukh
- Department of Chemistry, Assam University, Silchar-788011, Assam, India; Department of Physics, University of Colorado, Boulder, Colorado 80309, United States; National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, United States; Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado, 80309, United States; and Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, United States
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12
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Trivedi RP, Lee T, Bertness KA, Smalyukh II. Three dimensional optical manipulation and structural imaging of soft materials by use of laser tweezers and multimodal nonlinear microscopy. Opt Express 2010; 18:27658-27669. [PMID: 21197040 DOI: 10.1364/oe.18.027658] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We develop an integrated system of holographic optical trapping and multimodal nonlinear microscopy and perform simultaneous three-dimensional optical manipulation and non-invasive structural imaging of composite soft-matter systems. We combine different nonlinear microscopy techniques such as coherent anti-Stokes Raman scattering, multi-photon excitation fluorescence and multi-harmonic generation, and use them for visualization of long-range molecular order in soft materials by means of their polarized excitation and detection. The combined system enables us to accomplish manipulation in composite soft materials such as colloidal inclusions in liquid crystals as well as imaging of each separate constituents of the composite material in different nonlinear optical modalities. We also demonstrate optical generation and control of topological defects and simultaneous reconstruction of their three-dimensional long-range molecular orientational patterns from the nonlinear optical images.
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Affiliation(s)
- Rahul P Trivedi
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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13
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Zimmerley M, Younger R, Valenton T, Oertel DC, Ward JL, Potma EO. Molecular orientation in dry and hydrated cellulose fibers: a coherent anti-Stokes Raman scattering microscopy study. J Phys Chem B 2010; 114:10200-8. [PMID: 20684644 DOI: 10.1021/jp103216j] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with spontaneous Raman scattering microspectroscopy and second harmonic generation (SHG) microscopy to interrogate the molecular alignment in dry and hydrated cellulose fibers. Two types of cellulose were investigated: natural cellulose I in cotton fibers and regenerated cellulose II in rayon fibers. On the basis of the orientation of the methylene symmetric stretching vibration, the molecular alignment of cellulose microfibrils is found to be conserved on the micrometer scale. Whereas the molecular orientation in cotton shows modest variability along the fiber, the alignment of the cellulose units in rayon is highly consistent throughout the fiber. The ordered alignment is retained upon fiber hydration. Upon hydration of the cellulose fibers, an anisotropic electronic contribution is observed, which indicates an ordered incorporation of water molecules into the fiber structure. The third-order and second-order electronic polarizability of cellulose I are directed along the axis of the polyglucan chain. No second-order optical response is observed in cellulose II, supporting the antiparallel arrangement of the polyglucan chains in regenerated cellulose.
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Affiliation(s)
- Maxwell Zimmerley
- Department of Chemistry, University of California, Irvine, California 92697, USA
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Volkmer A. Coherent Raman Scattering Microscopy. Emerging Raman Applications and Techniques in Biomedical and Pharmaceutical Fields 2010. [DOI: 10.1007/978-3-642-02649-2_6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Baldacchini T, Zimmerley M, Kuo CH, Potma EO, Zadoyan R. Characterization of microstructures fabricated by two-photon polymerization using coherent anti-stokes Raman scattering microscopy. J Phys Chem B 2009; 113:12663-8. [PMID: 19715350 DOI: 10.1021/jp9058998] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We demonstrate the possibility to image microstructures fabricated by two-photon polymerization (TPP) using coherent anti-Stokes Raman scattering (CARS) microscopy. The imaging contrast based on chemical selectivity attained by CARS microscopy is used to gather qualitative information on TPP. Upon the basis of detailed knowledge of the characteristic signatures of the photoresist Raman spectrum, quantitative relationships between laser writing conditions and polymer cross-linking are demonstrated. The increase in degree of polymer conversion as a function of laser average power follows a sigmoidal profile which is interpreted in terms of a simple model based on the polymerization mechanism of the photoresist.
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Affiliation(s)
- Tommaso Baldacchini
- Technology and Applications Center, Newport Corporation, Irvine, California 92606, USA.
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Wang HW, Fu Y, Huff TB, Le TT, Wang H, Cheng JX. Chasing lipids in health and diseases by coherent anti-Stokes Raman scattering microscopy. Vib Spectrosc 2009; 50:160-167. [PMID: 19763281 PMCID: PMC2744966 DOI: 10.1016/j.vibspec.2008.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The integration of near IR picosecond pulse excitation, collinear beam geometry, epi-detection, and laser-scanning has produced a coherent anti-Stokes Raman scattering (CARS) microscope with a detection sensitivity of 10(5) vibrational oscillators, sub-micron 3D resolution, and video-rate acquisition speed. The incorporation of spectral detection and other imaging modalities has added versatility to the CARS microscope. These advances allowed sensitive interrogation of biological samples, particularly lipids that have a high density of CH(2) groups. With initial applications to membrane domains, lipid bodies, demyelinating diseases, obesity, and cardiovascular diseases, CARS microscopy is poised to become a powerful bio-imaging tool with the availability of a multifunctional, affordable, easy-to-operate CARS microscope, and the development of CARS endoscopy for in vivo diagnosis.
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Affiliation(s)
- Han-Wei Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Yan Fu
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Terry B. Huff
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Thuc T. Le
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Haifeng Wang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Ji-Xin Cheng
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
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Kachynski AV, Kuzmin AN, Prasad PN, Smalyukh II. Realignment-enhanced coherent anti-Stokes Raman scattering and three-dimensional imaging in anisotropic fluids. Opt Express 2008; 16:10617-10632. [PMID: 18607476 DOI: 10.1364/oe.16.010617] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We apply coherent anti-Stokes Raman Scattering (CARS) microscopy to characterize director structures in liquid crystals. We demonstrate that the polarized CARS signal in these anisotropic fluids strongly depends on alignment of chemical bonds/molecules with respect to the collinear polarizations of Stokes and pump/probe excitation beams. This dependence allows for the visualization of the bond/molecular orientations via polarized detection of the CARS signal and thus for CARS polarization microscopy of liquid crystal director fields, as we demonstrate using structures in nematic, cholesteric, and smectic liquid crystals. On the other hand, laser-induced director realignment at powers above a well-defined threshold provides the capability for all-optical CARS signal enhancement in liquid crystals. Moreover, since the liquid crystalline alignment can be controlled by electric and magnetic fields, this demonstrates the feasibility of CARS signal modulation by applying external fields to these materials.
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Affiliation(s)
- Aliaksandr V Kachynski
- The Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA
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Abstract
Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free imaging technique that is capable of real-time, nonperturbative examination of living cells and organisms based on molecular vibrational spectroscopy. Recent advances in detection schemes, understanding of contrast mechanisms, and developments of laser sources have enabled superb sensitivity and high time resolution. Emerging applications, such as metabolite and drug imaging and tumor identification, raise many exciting new possibilities for biology and medicine.
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Affiliation(s)
- Conor L Evans
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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