Sensitive wavelength-modulated photoacoustic spectroscopy with a pulsed optical parametric oscillator.
With a laser-excited acoustic wave as the carrier wave and by modulation of the light wavelength of a multikilohertz-repetition-rate optical parametric oscillator at a lower frequency than the acoustic frequency, we demonstrate a wavelength-amplitude double-modulation technique and achieve an enhancement factor of 35 in sensitivity in photoacoustic trace gas detection with the technique.
Ng
Jimmy
J
Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan.
Kung
A H
AH
Miklós
András
A
Hess
Peter
P