Abstract
We employ the finite-difference time-domain (FDTD) technique as a numerical approach to studying the effects of polarization, scatterers' sizes and orientations on near-field coherent anti-Stokes Raman scattering (CARS) microscopy imaging. The results show that to acquire better image contrast and larger near-field CARS signals, the scatterers with diameters of less than three-eighths of the pump field wavelength (lambda(p)) are preferable to be oriented along the polarization direction of the excitation light fields. It is also found that when the scatterers' sizes are smaller than half a wavelength of the pump field, the perpendicular polarization component of the induced near-field CARS radiations is strictly confined within the regions at the scatterer-water interface or the subsurface of scatterers, yielding a high image contrast (up to 200) with a spatial resolution of lambda(p)/16. This study indicates that perpendicular polarization components of near-field CARS microscopy could be used to uncover very fine structures of intra- and/or inter- cellular organelles in cells with nanoscale resolutions.
Highlights
Coherent anti-Stokes Raman scattering (CARS) microscopy is a nonlinear Raman imaging technique that has received great attention for biological and biomedical imaging due to its ability of real-time, nonperturbative chemical mapping of live unstained cells and tissue based on molecular vibrations [1,2,3,4,5,6,7,8]
CARS microscopy has been used to selectively identify cellular structures in live cells and tissue using the contrast provided by the spectral properties of lipids, proteins, nucleic acids, and water [4,5,6,7,8], as these molecular constituents are highly abundant in tissue and cells
Recent advances in CARS microscopy illustrate that this label-free molecular imaging technique can be combined with other nonlinear optical modalities (e.g., second-harmonic generation (SHG), third-harmonic generation (THG), two-photon excitation fluorescence (TPEF), etc.) for better characterization of various biochemicals and biomolecular structures and compositions in biomedical systems [12,13,14,15]
Summary
Coherent anti-Stokes Raman scattering (CARS) microscopy is a nonlinear Raman imaging technique that has received great attention for biological and biomedical imaging due to its ability of real-time, nonperturbative chemical mapping of live unstained cells and tissue based on molecular vibrations [1,2,3,4,5,6,7,8]. Recent advances in CARS microscopy illustrate that this label-free molecular imaging technique can be combined with other nonlinear optical modalities (e.g., second-harmonic generation (SHG), third-harmonic generation (THG), two-photon excitation fluorescence (TPEF), etc.) for better characterization of various biochemicals and biomolecular structures and compositions in biomedical systems [12,13,14,15]. We employ an advanced numerical technique- the finite-difference time-domain (FDTD) method [26,27,28] for investigating the influences of the excitation light polarization, the nanoparticles’ sizes and orientations on the induced near-field CARS radiations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
