Laser polarization noise elimination in sensitive polarimetric systems

The high throughput, low divergence, and quasimonochromatic characteristics of lasers make them desirable as light sources for numerous applications. Because of their extensive use, much work has been done to characterize laser noise. For laser applications in polarim- etry, a majority of this work has focused on laser output intensity fluctuations, which are primarily influenced by shot noise and flicker noise. Methods and algorithms have been developed to optimize signal to noise ratio (SNR) for polarimetric systems within both the shot-noise and flicker-noise limits. However, for systems that are extremely polarization state sensitive, such as those used for polarization imaging, the current optimization techniques still result in laser noise contributions that can contribute 10% or greater error to detected intensities. One potential source of these errors is a "wobble" in the polarization vector centered about the preferred polarization state of the laser output. We present a Mueller matrix theoretical analysis of this wobble phenomena. Our proposed solution for its elimination includes the introduction of a quarter- wave plate in the system. For this solution, we present experimental data that supports its viability.