Abstract

Spectroscopy methods including mid-infrared (MIR)-, coherent anti-Stokes Raman scattering (CARS)-, two photon excitation fluorescence (TPEF), second harmonic generation (SHG)- and sum frequency generation (SFG) microscopy are versatile analytical tools in life and material sciences [1]. Pathing the way for the development of an all-purpose laser excitation tool for multimodal microscopy, a vibrational resonant sum frequency (SF) spectroscopy technique is implemented in two approaches: a homodyne mid-infrared scanning and a heterodyne multiplexing scheme. This setup, which is already capable of TPEF, SHG, CARS and MIR microscopy [2], uses the flexibility of a programmable pulse shaper to shape the sub 10 fs near-infrared laser pulses. The pulse shaping provides in both approaches the spectral resolution by use of either Spectral Focusing [3] for monochromatic MIR light generation in the homodyne scanning mode or Double Quadrature Spectral Interferometry [4] for heterodyne amplified SF-signal generation in the multiplex mode.

© 2019 IEEE