Vibrational Imaging Based On Stimulated Raman Scattering Microscopy

We demonstrate a new implementation of coherent vibrational optical microscopy where image contrast is based on stimulated Raman scattering (SRS). SRS detection inherently maps the imaginary part of the third-order nonlinear susceptibility of a molecular vibration. The chemical contrast in SRS microscopy is thus inherently free of nonresonant nonlinear background signal and of spectral interferences between overlapping Raman bands. Experiments are presented that confirm these fundamental advantages of SRS microscopy when compared to coherent anti-Stokes Raman scattering (CARS) microscopy and demonstrate its potential for the noninvasive vibrational imaging of biological systems.