Abstract

Mid-infrared (MIR) spectroscopy is becoming increasingly popular for the study of complex molecules in a number of fields ranging from physics to biology and medicine. While molecular vibrations are usually indirectly probed by Raman-type processes, the direct resonant investigation with IR frequencies ranging from 500 – 3500 cm^-1 provides complementary contrast and far better coupling efficiencies. However, due to the limitations of available light sources and efficient detectors in the MIR region, spectroscopies in the visible or near-IR are still the methods of choice. Besides some promising new developments, most of the IR sources applied in laboratories today are based on the output available from difference frequency generation (DFG) stages mixing near-IR light in nonlinear optical crystals.

© 2017 IEEE