METHOD OF PREVENTING DECREASE IN TRANSMITTANCE DUE TO COLORING OF NONLINEAR OPTICAL CRYSTAL FOR WAVELENGTH CONVERSION

摘要

PROBLEM TO BE SOLVED: To easily prevent such a phenomenon that a nonlinear optical crystal used for wavelength conversion of a solid laser light is colored by the laser light and its transmittance decreases with time. SOLUTION: The nonlinear optical crystal used for wavelength conversion of a solid laser light is annealed in an environment containing water to permeate the water content into the crystal. Thus, decrease in the transmittance due to coloring of the crystal by repeated use can be prevented.