Saturated-absorption spectroscopy with low-power difference-frequency radiation

Abstract

We report high-resolution saturated-absorption spectra recorded by use of a few microwatts of radiation generated in a single pass by difference-frequency mixing. These results were obtained without the use of buildup cavities for the nonlinear mixing or for the saturation spectroscopy. We show high-quality saturated-absorption signals for the fundamental rovibrational band of CO(2) near 4.3 mum. Convenient sources and frequency-conversion devices open new possibilities for sub-Doppler spectroscopy in the infrared.

Mach-Zehnder interferometric system for measuring the refractive indices of uniaxial crystals

“…i(o, x, y) = a(x, y)+ b(x, y)cos[2rvx + (3) where a(x, y) and b(x, y) are the background of the intensity distribution and the amplitude of the interference fringes in the (x-y) CCD recording plane. They are supposed to be independent on the rotation angle 0 as well as slowly varying compared to the spatial frequency v along the x-axis.…”

Frequency conversion in novel materials and its application to high resolution gas sensing

“…Therefore, the resolution is limited also by the absorption linewidth. However, the narrow linewidth of the DFG-based spectrometer can be of great importance when performing sub-Doppler [20] or low-pressure measurements.…”

Difference-frequency generation as a precise tool for high-resolution spectroscopy

“…Only very recently, high-resolution sub-Doppler spectra have been recorded using these two nonlinear second-order processes [16][17][18] From the point of view of frequency control, difference frequency based sources are intrinsically more reliable than parametric amplifiers and oscillators. This is obviously due to the deterministic link between the difference frequency generated radiation and the two input laser frequencies.…”