Sensor for real-time determining the polarization state distribution in the object images

Abstract

An innovative real-time polarimetric method is presented based on the integral polarization-holographic diffraction element developed by us. This element is suggested to be used for real time analysis of the polarization state of light, to help highlight military equipment in a scene. In the process of diffraction, the element decomposes light incoming on them onto orthogonal circular and linear basis. The simultaneous measurement of the intensities of four diffracted beams by means of photodetectors and the appropriate software enable the polarization state of an analyzable light (all the four Stokes parameters) and its change to be obtained in real time. The element with photodetectors and software is a sensor of the polarization state. Such a sensor allows the point-by-point distribution of the polarization state in the images of objects to be determined. The spectral working range of such an element is 530 – 1600 nm. This sensor is compact, lightweight and relatively cheap, and it can be easily installed on any space and airborne platforms. It has no mechanically moving or electronically controlled elements. The speed of its operation is limited only by computer processing. Such a sensor is proposed to be use for the determination of the characteristics of the surface of objects at optical remote sensing by means of the determination of the distribution of the polarization state of light in the image of recognizable object and the dispersion of this distribution, which provides additional information while identifying an object. The possibility of detection of a useful signal of the predetermined polarization on a background of statistically random noise of an underlying surface is also possible. The application of the sensor is also considered for the nondestructive determination of the distribution of stressed state in different constructions based on the determination of the distribution of the polarization state of light reflected from the object under investigation. The prospect of this sensor application in astropolarymetry both for land and space telescopes is also discussed.