Low noise, intra-cavity frequency-doubling micro chip laser with wide temperature range

摘要

The present invention provides for a low noise, intra-cavity frequency-doubling; diode pumped micro chip laser with wide temperature range comprising pumping diode, gain medium, nonlinear crystal and temperature compensation element. The gain medium pumped by diode generates fundamental wavelength and the nonlinear crystal acts as second harmonic generator. The condition for the laser to work in “low noise operation” is that the nonlinear crystal formed by birefringent materials keeps a quarter wave plate to fundamental wavelength. Since the phase retardation of the plate is strongly relied on temperature, the temperature range of the laser with low noise is narrow. To expend the working temperature range, an additional birefringent material is utilized to compensate variation in phase retardation of the nonlinear material with temperature. It makes the laser in low noise operation in wider temperature range. The additional birefringent plate compresses the number of longitudinal modes also that further reduces “green noise”.