<title>Design and construction of a coherent light pupil imaging Stokes polarimeter for 1315 nm</title>

Abstract

An imaging polarimeter has been designed and constructed at the Air Force Phillips Laboratories to measure the polarization properties of laser speckle patterns. An imaging polarimeter spatially measures the polarization state of light coming from an object, thereby producing a "polarization image". The system described was designed to image the pupil of an optical system containing speckle patterns created by illumination of diffuse objects with light from a pulsed 1315 nm laser. Difficulties encountered due to demanding specifications required for polarimeter components and for coherent imaging systems in general are described and their solutions are discussed. Diagnostic techniques developed to measure path length differences and to identify the source of interference fringes are described. System calibration and characterization tests are described and results are presented.

<title>Design and construction of a four-channel 527-nm imaging polarimeter</title>

“…Experience has shown that adhesives used in cubes must closely match the index of refraction of the cube material, or fringe patterns are created by the glue/glass and glue/coating interfaces. 7 Coherent imaging systems are also particularly sensitive to dust and surface defects. Diffracted light from dust particles, surface defects and glue or glass inhomogeneities, create diffraction patterns that can spread out and degrade large areas of data.…”

<title>Performance limitations of a four-channel polarimeter in the presence of detection noise</title>

“…The polarimeter decomposes the input polarized light onto four channels whose respective intensity is measured by a photon counting camera. The intensity measurement made on each of the four detectors is denoted by the matrix I written as 10 1= (2) 13 where the spatially integrated intensity for each channel is ii = I I(x)WA(x) d2x (3) A is the area of the detector and WA (x) is the detector active area window function. The intensities are obtained from I = P S, where the input Stokes vector, S, having the units of tA limitation, however, is that an optical element that coherently combines two beams cannot be represented by a Mueller matrix.…”