We demonstrate real-time two-channel self-mixing laser-Doppler measurement with extreme optical sensitivity using a laser-diode-pumped thin-slice LiNdP4O12 laser. Successful carrier-frequency-division-multiplexed two-channel operations are realized by using one laser, two sets of optical frequency shifters, and a two-channel frequency-modulated-wave demodulation circuit. Simultaneous independent measurements of vibrations of speakers and averaged motions of small Brownian particles in different scattering cells are demonstrated. Self-mixing photon correlation spectroscopy of particle size distributions is also discussed.
© 2005 Optical Society of America
(120.7280) Instrumentation, measurement, and metrology : Vibration analysis
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3580) Lasers and laser optics : Lasers, solid-state
(290.1350) Scattering : Backscattering
(290.5850) Scattering : Scattering, particles
Kenju Otsuka, Kazutaka Abe, Natsumi Sano, Seiichi Sudo, and Jing-Yuan Ko, "Two-channel self-mixing laser Doppler measurement with carrier-frequency-division multiplexing," Appl. Opt. 44, 1709-1714 (2005)