Novel application of stimulated Raman scattering for high-resolution spectroscopic imaging utilizing its phase information

Abstract Raman scattering microscopy enables us to obtain chemical-contrast images with a high spatial resolution at the functional group level. This is because the Raman scattering signals derive from the normal vibrations of corresponding molecular and/or crystal structures. When stimulated Raman scattering (SRS), one of the coherent Raman scattering processes, is applied, not only the intensity but also the phase information of the chemical-contrast signal is preserved. Therefore extraction of the phase information by combining an optical interferometer with a Raman scattering microscope can lead to chemical-contrast imaging with higher spatial resolution, especially in the depth direction, than that of conventional optical Raman scattering microscope. The authors’ group has developed an SRS interferometer and a differential interference contrast SRS microscope for the first time, as core techniques for chemical-contrast topography and tomography with higher depth resolution than that of the conventional Raman scattering microscopy.