WAVELENGTH CONVERSION METHOD OF LASER BEAM AND WAVELENGTH CONVERSION DEVICE OF LASER BEAM

摘要

PURPOSE:To efficiently convert the fundamental wave outputted from a laser oscillator to a third higher harmonic wave by lowering SHG efficiency and optimizing the photon number ratio of a second harmonic wave and the fundamental wave. CONSTITUTION:At least either of the crystal angle or crystal temp. of a nonlinear optical crystal 15 for second harmonic wave generation is changed by a phase matching state adjusting device 18 to generate mismatching by a small quantity each in a phase matching state. The photon number ratio N2/N1 of the converted second harmonic wave and the fundamental wave remaining without being converted is made smaller than the value at which the SHG efficiency is maximized within a 0