ANTIREFLECTION FILM OF LASER ELEMENT

摘要

PURPOSE:To obtain the antireflection film to two wavelengths of the basic light and SH light of an SHG element by forming a 3-layered laminate which is formed with the respective layers to the optical film thicknesses of 1/4 the wavelength of incident laser light and is varied in the refractive index of the respective layers. CONSTITUTION:The respective layers of the antireflection film to the basic light and SH light at the incident and exit end face of the laser of the SHG element (second harmonic wave generating element) consisting of a KTP (KTiOPO4) crystal are formed to the film thicknesses of 1/4 the wavelength of the incident laser light. The 1st layer is formed to the refractive index higher than the refractive index of the KTP crystal, the 2nd layer is formed to the refractive index lower than the refractive index of the 1st layer and the 3rd layer is formed to the refractive index lower than the refractive index of the 2nd layer. Further, the refractive indices of the refractive index material layers of the three layers are selected so that the reflectivity to the wavelength of the basic light and the wavelength of the second harmonic wave attains <=0.2%.