High resolution self-mixing laser-Doppler vibrometry with a laser-diode-pumped microchip solid-state laser

Summary form only given. Laser-diode-pumped microchip, all-solid-stale laser 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 I photon per Doppler-beat cycle with a laser-diode-pumped microchip LiNdP/sub 4/O/sub 12/ (LNP) laser. The basic idea was to use an efficient self-mixing modulation effect through an interference between a laser beam and an extremely weak Doppler-shifted scattered field fed back into a microcavity laser resulting from an extremely large fluorescence-to-photon lifetime ratio in a microcavity laser. We applied this technique to laser-Doppler vibrometer systems (LVS) by contributing an LD-pumped LNP laser with acousto-optic frequency shifters (Bragg cells) and realized a high-resolution LVS without using any photon correlation technique.