| 摘要 |
PURPOSE:To stably provide high power second harmonic light beams by controlling the temperature of anisotropic solid-state laser medium so as to allow the output of wavelength changing beams to be minimum and permitting the azimuth of the anisotropic solid state laser medium to KTP crystal to be a prescribed angle. CONSTITUTION:The slight quantity of green light beams outputted from a sampling mirror 8 is sampled and intensity is detected by a photodetector 9. Then, a signal corresponding to the beam intensity is inputted to a control circuit 10. The control circuit 10 judges that the power of a semiconductor laser chip 1 is fixed and controls current that drives a Peltier element 7, which is used as a temperature control device, in order to permit the signal from the photodetector 9 to be extremely small. As a result, the temperature of solid-state laser medium 5 is controlled at 69 deg.C and high quality green light beams with low noise are provided. When the azimuth phi of the solid-state laser medium 5 to KTP crystal 6 is fixed at 45 deg., the temperature of the solid- state laser medium 5 is controlled at the same temperature regardless of the change of the retardation of the KTP crystal 6. |
