Abstract: An optical apparatus. More particularly, a laser sensitometer. The apparatus comprises: a polarized light source adapted to provide a Gaussian beam of light directed along an optical axis; a rotatable polarizer disposed in the optical axis adapted to vary an intensity of the beam of light, the polarizer being rotatable about the optical axis; and a rotatable polygon disposed in the optical axis, the polygon being rotatable about an axis perpendicular to the optical axis.

Abstract: An optical apparatus. More particularly, a laser sensitometer. The apparatus comprises: a polarized light source adapted to provide a Gaussian beam of light directed along an optical axis; a rotatable polarizer disposed in the optical axis adapted to vary an intensity of the beam of light, the polarizer being rotatable about the optical axis; and a rotatable polygon disposed in the optical axis, the polygon being rotatable about an axis perpendicular to the optical axis.

Abstract: A high speed, automatic calibration system of laser (or other light source) sensitometers capable of a wide range of power measurements, of densitometers and of other optical power measuring systems, and particularly to an automatic gain scaling circuit for use in the same. The system measures optical power incident on a photodiode detector in the course of calibrating or using a sensitometer and automatically and rapidly selects the appropriate gain for the operational amplifier. An automatic gain scaling function performed in gain scale logic rapidly selects the proper gain of a transimpedance operation amplifier operating as a current to voltage converter and delivers an analog voltage signal within a range between an upper limit and a lower limit. An over range error signal is generated in response to an upper out of limit signal generated at the minimum gain set by said gain scale logic.