Abstract

Laser-diode-pumped microchip, all-solid-state lasers have a wide variety of application because of their high efficiency, compact size, and potential for high beam quality. We recently demonstrated extremely sensitive laser-Doppler velocimetry (LDV) with a sensitivity below 1 photon per Doppler-beat cycle with a laser-diode-pumped microchip LiNdP₄O₁₂ (LNP) laser. The basic idea was to use an efficient self-mixing modulation effect through an interefence between a laser beam and an extremely weak Doppler-shifted scattered field fed back into a inicrocavity laser resulting from an extremely large fluorescence-to-photon lifetime ratio in a microcavity laser [1]. We applied this technique to laser-Doppler vibrometer systems (LVS) by combining an LD-pumped LNP laser with acousto-optic frequency shifters (Bragg cells) and realized a high-resolution LVS without using any photon­correlation technique.

© 2000 IEEE