%0 Journal Article
%T Differential high-resolution stimulated CW Raman spectroscopy of hydrogen in a hollow-core fiber
%A Philip G. Westergaard
%A Mikael Lassen
%A Jan C. Petersen
%J Physics
%D 2015
%I arXiv
%R 10.1364/OE.23.016320
%X We demonstrate sensitive high-resolution stimulated Raman measurements of hydrogen using a hollow-core photonic crystal fiber (HC-PCF). The Raman transition is pumped by a narrow linewidth (<50 kHz) 1064 nm continuous-wave (CW) fiber laser. The probe light is produced by a homebuilt CW optical parametric oscillator (OPO), tunable from around 800 nm to 1300 nm (linewidth ~ 5 MHz). These narrow linewidth lasers allow for an excellent spectral resolution of approximately 10^-4 cm^(-1). The setup employs a differential measurement technique for noise rejection in the probe beam, which also eliminates background signals from the fiber. With the high sensitivity obtained, Raman signals were observed with only a few mW of optical power in both the pump and probe beams. This demonstration allows for high resolution Raman identification of molecules and quantification of Raman signal strengths.
%U http://arxiv.org/abs/1506.04516v1