Highly sensitive low-frequency Raman spectroscopy enabled by Sagnac-enhanced impulsive stimulated Raman scattering (Conference Presentation)

By virtue of its chemical specificity and label-free nature, Raman spectroscopy is a ubiquitous tool in analytical chemistry which has recently found increasing interest in biology and medicine, as technical improvements steadily enable applications. In particular, the low-frequency region of the Raman spectrum, which contains rich information about intermolecular interactions and higher-order structure, has promise for biological applications. However, detection of low-frequency modes remains a challenge with conventional techniques for Raman spectroscopy. Here, we propose and experimentally demonstrate Sagnac-enhanced impulsive stimulated Raman scattering (SE-ISRS), a method for time-domain Raman spectroscopy that provides highly sensitive low-frequency Raman spectra at all probe frequencies.