Transmission imaging polarimetry for a linear birefringent medium using a carrier fringe method

Partial Mueller matrix polarimeter using liquid crystal modulators

A simple partial Mueller polarimeter is described, consisting of two linear polarizers and two liquid crystal variable retarders. The measurement leads to an incomplete Mueller-Scierski matrix, in which the elements from the third row and the third column are simultaneously missing. The proposed procedure for determining information about the birefringent medium from such an incomplete matrix is based on numerical methods and carrying out measurements with the rotated azimuthal sample. Acquired from the obtained results, the missing elements of the Mueller-Scierski matrix are reconstructed. The correctness of the method was verified by numerical simulations and test measurements.

Polarization calibration with large apertures in full field of view for a full Stokes imaging polarimeter based on liquid-crystal variable retarders

Currently, polarization calibration for full Stokes imaging polarimeters is limited by the apertures of the retarders. In this paper, an improved polarization calibration with large apertures in full field of view for full Stokes imaging polarimeters based on liquid-crystal variable retarders is proposed and investigated theoretically and experimentally. The experimental precision of polarization calibration is 1.7% for linear polarization states and 8.8% for circular ones for an imaging polarimeter with a 100 mm aperture and 10° field of view. The feasibility for full Stokes polarization image is also confirmed in experiment for identifying objects due to degree of polarization and degree of circular polarization images.

Adjustment method of an imaging Stokes polarimeter based on liquid crystal variable retarders

The description of adjustment of an imaging Stokes polarimeter constructed and tested in our laboratory is presented. Our polarimeter's operation is based on six fast intensity distribution measurements realized in six different configurations of linear and circular analyzers. Using liquid crystal variable retarders (LCVRs) makes this construction compact and mechanically simple. However, new problems arise with proper azimuthal alignment as well as with proper LCVR voltage adjustment. Three basic steps of the adjustment procedure adapted to the specific construction of our polarimeter are described in detail. Some remarks concerning the critical parameters of the used CCD camera's parameters are also presented, as well as experimental verifications of the setup's accuracy acquired due to the proper adjustment process.

Dynamic polarization states and birefringence distributions measurements in spatial elliptical polariscope using Fourier analysis method

A new method to measure the light polarization state and the birefringent media parameters is proposed. We have used the setup described previously, consisting of two pairs of the linear Wollaston and circular compensators which form a set of two spatially modulated elliptical compensators. We have modified this setup introducing some carrier frequencies in all compensators and assuming that the second linear one would introduce the frequency which is a multiplicity of the basis frequency of the first linear compensator. Both of these modifications allow calculating all polarization parameters of polarized light or birefringent medium from only one measured intensity distribution of the light outcoming the described setup. They allow measuring not only the parameters of homogeneous beams/mediums but also x,y-distributions of all desired parameters, like azimuth and ellipticity angles of the light or first medium eigenvector and the phase difference introduced by this medium. The proposed calculation method comprises of Fourier analysis of obtained intensity distribution with some manipulation of coordinate system and filtration of obtained data. This method is claimed to be simple and fast enough to be treated as a real-time method.

Measurements of birefringent media properties using optical vortex birefringence compensator

We present some applications of the optical vortex birefringence compensator, based on the C polarization type singularities generated using two Wollaston compensators. The theory and experimental results of birefringent media properties measurements are presented. The possibility of the simultaneous measurement of both the azimuth angle and the phase retardance has been analyzed and experimentally verified.