Lock-in white-light-interferometry-based all-optical photoacoustic spectrometer
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Updated: Feb 3, 2026

Three-dimensional Optical-resolution Photoacoustic Microscopy
Published on: May 3, 2011
Abstract:
An all-optical photoacoustic spectroscopy based on lock-in white-light interferometry is proposed for trace gas detection. The cavity length of the fiber-optic Fabry-Perot cantilever microphone is demodulated by a high-speed white-light interferometer, whose spectral sampling is synchronously triggered by a phased locked signal. To improve the signal-to-noise ratio, the demodulated digital photoacoustic signal is further processed by a specially designed virtual lock-in amplifier. The designed photoacoustic spectrometer has been tested for trace acetylene (C2H2) detection in the near-infrared region. The normalized noise equivalent absorption coefficient for C2H2 is achieved to be 1.1×10-9 cm-1 W Hz-1/2.
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