Production of arbitrary polarized light beams with a liquid crystal spatial modulator

Abstract

In this paper, we review some of our recent advances in the generation and control of polarized light beams by means of liquid crystal light modulators. We use a reflective geometry where a single parallel-aligned spatial light modulator device is used to independently spatially modulate two orthogonal linear polarizations with two different phase profiles. In this way we are able to produce arbitrary polarization patterns, which can be combined to produce polarization diffractive elements. In this work we present two such new elements: 1) an anisotropic axicon capable to produce a line focus with axial arbitrary state of polarization, and 2) anisotropic diffraction gratings, capable to generate arbitrary orders of diffraction with different states of polarization designed at will. The anisotropic axicon generates a Bessel beam with polarization variation, which might be useful in micro-fabrication techniques. On the other hand, the anisotropic gratings are useful to produce snapshot polarimeters, capable to measure the Stokes parameters of a light beam in a single measurement. Finally, we will show that these elements can be combined with spiral phase patterns in order to convert them into cylindrically polarized light beams. Experimental results on the production of diffractive elements that generate light beams with these polarization features will be included.