Highly efficient cw frequency doubling of 854 nm GaAlAs diode lasers in an external ring cavity

摘要

We report on 50% conversion efficiency for frequency doubling of a 854 nm GaAlAs diode laser using a potassium niobate crystal in an external ring cavity. Frequency stabilization of the diode laser is achieved by direct optical feedback from the doubling cavity or from a grating in Littrow configuration. We determine 200 kHz linewidth from the measured spectral density of the frequency noise and from a beat signal measurement of two independent diode lasers. The blue output power of 7.8 mW shows rms-fluctuations of less than 0.6% in 1 MHz bandwidth.