Frequency-stable operation of a diode-pumped continuous-wave RbTiOAsO_4 optical parametric oscillator

Frequency-stable operation of a diode-pumped continuous-wave optical parametric oscillator (OPO) of RbTiOAsO₄ is demonstrated. Piezoelectric and fast electro-optic control of the optical length of the two-mirror OPO cavity (resonant for the pump and the idler waves) compensates for thermal changes in the refractive index of the OPO crystal (induced by absorption of pump light) and acoustic perturbations of the cavity length. Pumped by 405 mW of the 810-nm output of a GaAlAs master-oscillator-tapered-amplifier diode laser system, the OPO generates a power-stable single-frequency signal wave at 1.24 $\mathit{\mu }\mathrm{m}$ with an output of 84 mW and a spectral bandwidth of less than 10 MHz.