Stimulated Raman Scattering Interferometer for Molecular-Selective Tomographic Imaging

Development of a stimulated Raman scattering (SRS) interferometer is presented. In the apparatus, a SRS signal generated in a sample is collinearly overlapped with a reference beam, and the interference pattern between the signal and reference beams is obtained. From the interference pattern, the phase of the SRS signal can be measured. From the phase of the signal, the spatial distribution of the target molecule can be obtained with high positioning precision. In the present article, the SRS interferometer was developed and the first SRS interference signal was obtained from a polyethylene film. The phase change of the SRS interference pattern caused by scanning the sample position along the direction of the incident light propagation was measured. From the result, the sample position difference for a sub-micron was detected with uncertainties of 15%. The tomographic images of a triple-layered polymer film were successfully obtained. The SRS interferometer would become a core optical technique of a novel molecular-selective tomographic imaging method.