We introduce a widefield CARS microscope implementation that uses a spatial light modulator to obtain extremely precise control over the pump/probe-beam incidence geometry, which provides the possibility to enhance the image contrast at specific target resonances by fine-tuning the incidence angles. We show how this technique can be used to optimize the image contrast between objects of different size and to practically eliminate the undesired signal from the solvent that embeds small target specimens. Changing the numerical aperture of the illumination from 1.27 to 1.24 improved the ratio of the signals of 500 nm polystyrene beads and the agarose solvent by about 20 dB.
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http://dx.doi.org/10.1364/OL.36.002245 | DOI Listing |
Small Methods
October 2024
Optical Bioimaging Laboratory, Department of Biomedical Engineering, College of Design and Engineering, National University of Singapore, Singapore, 117576, Singapore.
Fourier ptychography (FP) is a high resolution wide-field imaging method based on the extended aperture in the Fourier space, which is synthesized from raw images with varying illumination angles. If FP is extended to coherent nonlinear optical imaging, the resolution could be further improved due to the increase of the cutoff frequency of the synthesized coherent optical transfer function (C-OTF) with respect to the order of nonlinear optical processes. However, there is a fundamental conflict between wide-field FP and nonlinear optical imaging, whereby the nonlinear optical imaging typically requires a focused excitation laser beam with high power density.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
May 2022
Department of Chemistry, University of California, Irvine, CA 92697, USA.
Lasers Surg Med
August 2022
Department of Dermatology, Copenhagen University Hospital, Bispebjerg and Frederiksberg, Copenhagen, Denmark.
Purpose: Conventional oral antifungal therapies for onychomycosis (OM) often do not achieve complete cure and may be associated with adverse effects, medical interactions, and compliance issues restricting their use in a large group of patients. Topical treatment can bypass the systemic side effects but is limited by the physical barrier of the nail plate. Ablative fractional laser (AFL) treatment can be used to improve the penetration of topical drugs into the nail.
View Article and Find Full Text PDFCells
July 2021
Department of Systems and Computer Engineering, Faculty of Engineering and Design, Carleton University 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada.
Biological tissues are not uniquely composed of cells. A substantial part of their volume is extracellular space, which is primarily filled by an intricate network of macromolecules constituting the extracellular matrix (ECM). The ECM serves as the scaffolding for tissues and organs throughout the body, playing an essential role in their structural and functional integrity.
View Article and Find Full Text PDFAnalyst
May 2021
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Nonlinear optical microscopy that leverages an objective based total internal reflection (TIR) excitation scheme is an attractive means for rapid, wide-field imaging with enhanced surface sensitivity. Through select combinations of distinct modalities, one can, in principle, access complementary chemical and structural information for various chemical species near interfaces. Here, we report a successful implementation of such a wide-field nonlinear optical microscope system, which combines coherent anti-Stokes Raman scattering (CARS), two-photon fluorescence (TPF), second harmonic generation (SHG), and sum frequency generation (SFG) modalities on the same platform.
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