METHOD FOR EVALUATING INFRARED OPTICAL CRYSTAL AND METHOD FOR EVALUATING OPTICAL FIBER FOR INFRARED LIGHT

摘要

PURPOSE:To make non-destructive evaluation at approximately 100% yield by irradiating an IR optical crystal with a visible region wavelength laser and observing the scattered light generated from internally existing defects and impurities with an optical microscope. CONSTITUTION:The optically polished IR optical crystal 3 is irradiated with the laser beam 2 consisting of the He-Ne laser beam generated from an oscillator 1 and having the visible region wavelength. The focus is matched with the optical path of the laser beam 2 from the side face of the crystal 3 with the optical microscope 4 in this state and the crystal is observed. The scattering is generated and can be detected when the defects and impurities exist in the optical path of the laser beam 2 in the crystal 3. The non-destructive evaluation is made at the good yield in this way.