Stable continuous-wave single-frequency intracavity frequency-doubled laser with intensity noise suppressed in audio frequency region**Project supported by the National Key R&D Program of China (Grant No. 2016YFA0301401).

Abstract

We demonstrated a continuous wave (cw) single-frequency intracavity frequency-doubled Nd:YVO4/LBO laser with 532 nm output of 7.5 W and output of 3.1 W, and low intensity noise in audio frequency region. To suppress the intensity noise of the high power 532 nm laser, a laser frequency locking system and a feedback loop based on a Mach–Zehnder interferometer were designed and used. The influences of the frequency stabilization and the crucial parameters of the MZI, such as the power splitting ratio of the beam splitters and the locking state of the MZI, on the intensity noise of the 532 nm laser were investigated in detail. After the experimental optimizations, the laser intensity noise in the frequency region from 0.4 kHz to 10 kHz was significantly suppressed.