| 摘要 |
PROBLEM TO BE SOLVED: To obtain a low-noise 2nd harmonic generating device, by controlling the oscillation frequency of basic wave to the minimum value of phase matching wavelength characteristics of nonlinear optical crystal(SHG crystal) and generating a 2nd harmonic. SOLUTION: The exciting beam 31 emitted by a semiconductor laser 11 is converged by a convergence optical system 12 to excite solid-state laser crystal 4. The solid-state laser crystal 4 generates a 1st oscillation wave as the basic wave and a laser resonator consisting of an incidence-side laser mirror 3 as a curvature mirror and a laser mirror 7 which is formed on the projection end surface of the SHG crystal 6 and reflects the 1st oscillation wave generates the basic wave as the 1st oscillation wave. A birefringent filter formed of one crystal plate is used for a wavelength control element 5, and arranged at the Brewster angle to the optical axis and rotated on the optical axis to perform wavelength control, thereby matching the wavelength of the basic wave with the minimum value of phase matching wavelength characteristics of the SHG crystal 6. |
