Impulsive SRS microscopy

Impulsive spectroscopy provides a time-domain perspective of the active Raman modes of the specimen. As such, it serves as a complementary tool for the more common narrowband stimulated Raman techniques. In this chapter, we introduce the reader to the time-domain picture of vibrational excitation and detection, and discuss the advantages and disadvantages as compared to the narrowband variant of Raman scattering. We then proceed with mentioning recent advances in the experimental apparatus, aiming both at increasing the SNR and at increasing the delay scanning rate which constitutes a critical element in such time-domain techniques. We end up discussing preresonant impulsive Raman microspectroscopy and 2D impulsive Raman spectroscopy.