Abstract

The complexity of experimental schemes still challenges the broad application of multimodal microscopy beyond fundamental research. Pulse shaping has been a promising candidate to assist in the implementation of flexible and compact schemes. In this work, its application is demonstrated for vibrational resonant sum frequency (SF) spectroscopy in a nonlinear Raman microscope. The mixing of an ultrabroadband NIR laser pulse with a difference-frequency-generated MIR spectrum provides spectral access from ${1750}\,\,{{\rm cm}^{ - 1}}$ to beyond ${3000}\,\,{{\rm cm}^{ - 1}}$ via two shaping methods: (i) homodyne MIR scanning and (ii) heterodyne multiplex. The versatility of shaper-based SF is demonstrated in the spectroscopy and microscopy of crystalline cholesterol and cysteine.

© 2019 Optical Society of America