| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent decline in power of the outputted higher harmonic laser beams and deterioration in stability of the output, when a repeat frequency of a fundamental harmonic laser beam is changed. SOLUTION: A fundamental harmonic laser beam, outputted from a fundamental harmonic laser device 1, is projected into a nonlinear optical crystal (SHG crystal) 6 for generating a double wave via isolator 2, amplifier 3, amplifier 4, and second harmonic generating optical system 5, and its wavelength is converted into a double- wave laser beam. The fundamental harmonic laser beam projected from the SHG crystal 6 and the double-wave laser beam are projected into a nonlinear optical crystal 8 for generating sum frequency through a sum frequency generating optical system 7. The nonlinear optical crystal 8 generates the sum frequency laser beam. A controller 10 amplifiers current values of the amplifies 3 and 4 according to the enhancement of a repetitive frequency of the fundamental harmonic layer beam. As a result, the peak power of the fundamental harmonic laser beam projected into the SHG crystal 6 can be increased and the decline in power of the outputted higher harmonic laser beam can be restrained, and further deterioration of the stability of output can be prevented.</p> |
