| 摘要 |
PROBLEM TO BE SOLVED: To provide the method and device for optical harmonic generation which can lead high mean output out with high efficiency while preventing crystal destruction and crystal deterioration. SOLUTION: The laser light of wavelengthλemitted by a laser device 1 is branched by a half-mirror 5 into a 1st laser light and a 2nd laser light, which are made incident on nonlinear optical crystals 2a and 2b to generate higher harmonic lights of wavelengthλ/2. The output lights of the nonlinear optical crystals 2a and 2b are spectrally diffracted by prisms 3a and 3b to extract higher harmonic lights of wavelength #;/2, and the polarization azimuth of one higher harmonic light is rotated by 90 deg. through a 1/2-wavelength plate 7; and the output lights of the prism 3a and 1/2-wavelength plate 7 are made incident on a polarization beam splitter 8 and the higher harmonic lights having mutually orthogonal polarization azimuths are put one over the other. Here, the polarization azimuths of the 1st and 2nd laser lights may be different from each other by using a polarization beam splitter instead of the half-mirror 5 without using the plate 7.
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