Coherence and polarization properties in speckle of totally depolarized light scattered by totally depolarizing media

Probing the enpolarization phenomenon in a speckle pattern using a microwave photonics-inspired approach

We report how Stokes polarimetry of a highly resolved optical speckle pattern coupled to an original microwave photonics-inspired experimental approach allows new light to be shaded on the so-called enpolarization phenomenon, which consists in the local increase of the light degree of polarization (DOP) inducing a high average DOP value after interaction of unpolarized light with a totally depolarizing sample.

Optimization design and performance analysis of quaternion spatial pseudo-depolarizer

In this study, to improve the uniformity of transmission light intensity of depolarizer, we present an optimal design of the quaternion space pseudo-depolarizer consisting of four wedge crystals. By designing the optical axis and wedge angle of each crystals, the square distribution of the output spot is realized. The mathematical expression of the degree of depolarization is obtained using the light wave superposition method. Theoretical analysis shows that the new type of depolarizer can optimize the intensity distribution of the emergent light field when the depolarizer wedge angle is sufficiently large, and it can realize the perfect depolarization of monochromatic linear polarized light. A samples of the quartz crystal material are developed and tested using lasers of 405 nm and 670 nm wavelengths. The degree of depolarization is observed to be 99% for any azimuth angle, whereas the angle of field of view is −10°–10°.

Arbitrary state of polarization with customized degree of polarization generator

An optical setup able to generate arbitrary states of polarization (SOPs) with customized degree of polarization is presented in this Letter. Compared with the few alternatives existing in literature, it presents an easy-to-build optical setup and leads to a superior performance. In fact, experimental results are presented, providing an accurate control for the generation of SOPs (maximum error of 1.7% and 3.3% for ellipticity and azimuth, respectively) as well as for the associated degree of polarization (full experimental variation from 1 up to 0.003, with a 1.7% maximum error). The system proposed may be useful for different applications, for example, for polarimeters testing, speckle metrology, and biological applications.

Synthesis of statistical properties of a randomly fluctuating polarized field

An experimental technique for the synthesis of statistical properties of a randomly fluctuating polarized field is investigated and experimentally demonstrated. The technique offers the controlled synthesis of coherence and polarization and subsequent analysis of the synthesized field is carried out by making use of two-point intensity correlation and the speckle holographic technique. The controlled synthesis is achieved by using an aperture of specific size at the source plane and generating a vortex in one of the orthogonal polarization components of the polarized field, thereby producing a singularity in off-diagonal elements of the coherence-polarization matrix.

Optical systems for controlled specular depolarization

Optical coatings are known to be highly polarizing at oblique incidence. On the other hand, they cannot reduce the degree of polarization of light. We show how to overcome this difficulty and reach spatial depolarization with significant efficiency. Applications concern space optical systems.

Accurate metrology of polarization curves measured at the speckle size of visible light scattering

An optical procedure is presented to measure at the speckle size and with high accuracy, the polarization degree of patterns scattered by disordered media. Whole mappings of polarization ratio, polarimetric phase and polarization degree are pointed out. Scattered clouds are emphasized on the Poincaré sphere, and are completed by probability density functions of the polarization degree. A special care is attributed to the accuracy of data. The set-up provides additional signatures of scattering media.

Enpolarization and depolarization of light scattered from chromatic complex media

Influence of the variations of the scattering properties of a disordered medium with respect to frequency on the polarization of scattered light is investigated. We focus on the strongly scattering regime with the sum of random phasors scattering model that is extended to chromatic media and made frequency-sensitive. It is numerically shown how the scattered polarization depends on the incident polarization and the incident light bandwidth to scattering coefficients chromatic length ratio. Under the presented approach, both phenomena of depolarization and enpolarization of light appear unified.

Mapping the coherence time of far-field speckle scattered by disordered media

The polarization and temporal coherence properties of light are altered by scattering events. In this paper, we follow a far-field approach, modelizing the scattering from disordered media with the scattering matrix formalism. The degree of polarization and coherence time of the scattered light are expressed with respect to the characteristics of the incident field.

Light enpolarization by disordered media under partial polarized illumination: the role of cross-scattering coefficients

We show how disordered media allow to increase the local degree of polarization (DOP) of an arbitrary (partial) polarized incident beam. The role of cross-scattering coefficients is emphasized, together with the probability density functions (PDF) of the scattering DOP. The average DOP of scattering is calculated versus the incident illumination DOP.