title: Development of a multiplex stimulated Raman microscope for spectral imaging through multi-channel lock-in detection.
abstract: We report the development of a multiplex stimulated Raman microscope for spectral imaging through multi-channel lock-in detection with a single light source. A white pump beam is prepared with a piece of photonic crystal fiber (PCF). The system does not require the synchronization of plural light sources or the scanning of their wavelengths, and thus a jitter-free pair of pump and Stokes beams is obtained, and a high degree of temporal synchronization is attained in the spectra. The multi-channel lock-in detection (extended to 128 channels) enables the observation of pseudo-continuous stimulated Raman spectra, demonstrating the strong ability of qualitative analysis to identify various types of C-H stretching modes such as the symmetric and asymmetric modes of the methylene∕methyl and aromatic groups. Images of a mixed film of polystyrene and polymethylmethacrylate are presented to demonstrate the system's spectral imaging ability. The spatial distribution of these materials is successfully captured through one-time imaging, although the noise of the white light pump beam generated with the PCF limits the system's imaging speed.
authors.affiliation: Department of Applied Physics and Chemistry and Institute for Laser Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Seto
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Okuda
authors.forename: Eiji
authors.initials: E
authors.lastname: Tokunaga
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Kobayashi
mesh_terms: D008027:Light; D008853:Microscopy / Q000295:instrumentation*; D055100:Optical Fibers; D013059:Spectrum Analysis, Raman