[16p-A502-1~14] 3.7 Optical measurement, instrumentation, and sensor (formerly 3.8)

[16p-A502-4] Chemical-Structure Sensitive Nonlinear Dynamic Light Scattering based on Stimulated Raman Effect

〇Keisuke Seto¹, Takayoshi Kobayashi², Eiji Tokunaga¹ (1.Tokyo Univ. Sci., 2.NYCU)

Keywords:stimulated Raman, dynamic light scattering, correlation spectroscopy

Dynamic light scattering (DLS) analyzes mesoscopic structures such as particle size distribution and drift velocity in a suspension and correlation length of gel based on fluctuation in refractive index. Here, the scattered field detected in DLS is proportional to a spatial Fourier component of the refractive index. However, DLS lacks chemical sensitivity. We propose a molecular-vibration-selective nonlinear dynamic light scattering method based on the stimulated Raman scattering (SRS) effect. An SRS signal is proportional to the intensity of the pump beam (in the pump/probe terms). In the present method, two pump beams interfere to generate sinusoidal intensity modulation, which generates the signal proportional to the spatial Fourier component of the SRS effect. This method allows for unlabeled, chemical-structure-resolved mesostructural analysis.