Supercontinua for high resolution absorption multiplex infrared spectroscopy

TL;DR

This paper demonstrates the use of supercontinuum light sources generated by ultrashort-pulse lasers in highly non-linear fibers for high-resolution infrared absorption spectroscopy, achieving high spectral radiance and rapid spectral recording.

Contribution

It introduces a practical ultrabroadband supercontinuum source based on a Cr^4+:YAG femtosecond laser and photonic crystal fiber for high-resolution IR spectroscopy.

Findings

Spectral radiance exceeds blackbody and synchrotron sources.

C_2H_2 and NH_3 spectra recorded within seconds.

Broad spectral range from 675 to 2200 nm achieved.

Abstract

Supercontinua generated in highly non-linear fibers by ultrashort-pulse lasers can be used for high resolution Fourier transform absorption spectroscopy. The practical advantages of these bright ultrabroadband light sources for spectroscopy are reported in the near-infrared region. A Cr^4+:YAG femtosecond laser broadened by an extruded soft-glass photonic crystal fiber, emitting from 1200 to 2200 nm and from 675 to 950 nm, provides a spectral radiance being 1x10^5 times higher than that of a 3000 K blackbody and 10^2 times higher than that of a synchrotron radiation. The C_2H_2 and NH_3 overtone spectra are recorded using this source within a few seconds.