Patent ID: 7209504

Claim:
A solid laser apparatus comprising: a semiconductor laser for emitting a laser beam, a microchip laser crystal arranged for being excited by the laser beam emitted from the semiconductor laser and provided with crystal end faces coated for use as an optical resonator, a nonlinear optical device for receiving a laser beam from the microchip laser crystal and emitting a harmonic light of the laser beam, an optical detecting means used as a monitor for detecting an intensity of the harmonic light emitted from the nonlinear optical device, and an output control circuit for driving the semiconductor laser so as to maintain the intensity of the harmonic light at a predetermined level, wherein the output control circuit includes: a high-speed feedback circuit having a phase shift circuit for advancing the phase of a signal in vicinity of relaxation oscillating frequency of the solid laser apparatus to effect attenuation of noise in the vicinity of the relaxation frequency; and a low-speed feedback circuit arranged in parallel with the high-speed feedback circuit.