Extension of the dynamic range of the intracavity method of measuring optical densities

A technique was developed for the measurement of a wide range of optical densities of materials. This technique utilizes a laser with a three-mirror resonator and obviates the need for similar optical densities of the sample and calibration material. The method was tested using a helium–neon laser for nonphototropic materials and plasmas, and using an organic dye laser with selective losses introduced into the resonator.