Optimization of retardance for a complete Stokes polarimeter

We present two figures of merit based on singular value decomposition, which can be used to assess the noise immunity of a complete Stokes polarimeter. These are used to optimize a polarimeter featuring a rotatable retarder and a fixed polarizer. A retardance of 132 degrees (approximately three-eighths wave) and retarder orientation angles of +/-51.7 degrees and +/-15.1 degrees are found to be optimal when four measurements are used. Use of this retardance affords a factor-of-1.5 improvement in signal-to-noise ratio over systems employing a quarter-wave plate. A geometric means of visualizing the optimization process is discussed, and the advantages of the use of additional measurements are investigated. No advantage of using retarder orientation angles spaced uniformly through 360 degrees is found over repeated measurements made at the four retarder orientation angles. (C) 2000 Optical Society of America OCIS codes: 120.5410, 120.2130, 260.2130, 260.5430, 100.3190.