Remote sensing of polarimetric speckle

The polarimetric probability distribution functions (PDFs) of laser speckle for incident linear and circular polarization states have been determined from the measured Stokes parameters for a limited range of targets that may be encountered in remote sensing applications: two rough surface samples, and two samples which exhibit both surface and volume scattering. The resul tant speckle patterns of the total intensity are found to be partially pola rized with variations in the contrast and degree of polarization between sa mples and with incident polarization state. The intensity PDFs are compared to published theory expressed in terms of the sum of completely polarized and unpolarized speckle patterns. This theory is modified to incorporate sp eckle averaging caused by an imperfectly aligned rotating optical component , The measured ellipticity and azimuth PDFs were shown to be reasonably wel l predicted by a model based on the degree of polarization of the speckle p attern and the incident polarization state. The PDFs are shown to be useful in highlighting experimental problems that would have been less obvious by other methods. In addition, it is noted that the global polarimetric param eters provide valuable insight into speckle statistics, which is less appar ent than using only the intensity information.