Method of detecting harmful material

摘要

The method involves the use of optical absorption. Light of two different wavelengths from a laser (I2) is passed through the specimen. The longer (v3) and/or shorter (v2) wavelength light is absorbed resonator internally in an optical parametric oscillator by the material. The absorption is detected from the decrease in intensity of the shorter wavelength frequency. The measurement of wavelength is performed using the temp. of a non-linear crystal (I1).