BORATE-BASED NONLINEAR OPTICAL CRYSTAL DEVICE AND WAVELENGTH CONVERTING DEVICE USING THAT DEVICE

摘要

PROBLEM TO BE SOLVED: To provide optical parts for UV rays which can maintain optical uniformity for a long time even in air by controlling the absorption of water through the side face of a borate-based nonlinear optical crystal device. SOLUTION: The borate-based nonlinear optical crystal device shows little change in the distribution of the refractive index with time, and a carbide layer is formed on the side face except for the entrance and exit faces for rays. The wavelength converting device uses the borate-based nonlinear optical crystal device and includes as the structural elements, the nonlinear optical crystal device which allows the laser light to enter, converts the wavelength and generates harmonic waves, a crystal holding means to hold the crystal, and a chassis which surrounds the crystal and has an entrance hole where the laser light enters and an exit hole where the harmonic waves with converted wavelength exit. The nonlinear optical crystal device consists of a borate-based nonlinear optical crystal having a carbide layer on the side face except for the entrance and exit faces for laser light.