Method for changing a wavelength of a laser light

摘要

The efficiency of wavelength conversion of laser light can be improved by allowing incident laser light to pass through nonlinear optical crystals a multiple of times. In converting the wavelength of laser light to generate second- and higher harmonic waves, a returning mirror, a polarizer and nonlinear optical crystals are combined and the rotation of polarized light is utilized to allow the incident laser light to undergo multiple passes through the nonlinear optical crystals so that it can be converted in wavelength with higher efficiency.