可変波長レーザーを用いない非線形ラマン分光法による大気中微量分子の検知 Detection of Trace Molecules in the Atmosphere by Nonlinear Raman Spectroscopy without a Tunable Laser
A new technique for nonlinear Raman spectroscopy is proposed and discussed theoretically in terms of the detection of gas molecules in atmospheric pressure. In the proposed scheme, only a pulsed Nd: YAG laser is used as a pumping source, and instead of a tunable laser, a Raman shifter filled with the sametype of gas as that to be detected automatically generates the Raman shifted radiation. The detection limits of H<SUB>2</SUB>for SRGS (Stimulated Raman Gain Spectroscopy), PARS (Photo-Acoustic Raman Spectroscopy), and CARS (Coherent Anti-Stokes Raman Spectroscopy) are demonstrated experimentally, and the ppm order detection limit can be achieved by PARS. Although the sensitivity of CARS is smaller than that of PARS, the signal tonoise ratio in higher concentration is more effective.
レーザー研究 27(3), 194-198, 1999-03
The Laser Society of Japan