Photoanisotropic polarization gratings beyond the small recording angle regime

Abstract

Abstract:Polarization gratings can be realized by polarization holographic recording in photoanisotropic materials. In this paper, we study two types of polarization gratings. One is recorded with two orthogonally circularly (OC) polarized beams and the other one with two orthogonally linearly (OL) polarized beams. The interference of both cases is explored beyond the small recording angle regime. A novel method is proposed to represent the polarization states of the modulation. The diffraction by polarization gratings is studied with rigorous diffraction theory. Simulations based on the Finite Element Method are performed for both OC and OL polarization gratings at small and large recording angles.

Surface-relief and polarization gratings for solar concentrators

“…With the analysis of surface-relief gratings from Section 3 in mind, we may wonder whether these properties are not just a consequence of the fact that the polarization gratings that were studied could be considered as thin. In this section we experimentally verify the good angular acceptance that was found numerically by Xu et al [11] for large-period polarization gratings and study to what extend it still holds for small periods, useful for in-coupling applications (Λ λ ).…”

“…η 0 thus vanishes when the thickness and wavelength are related by d = λ /2∆n. Furthermore, previous simulations indicated that the diffraction efficiency of polarization gratings is relatively insensitive to the angle of incidence [11]. Based on these arguments, they seem to be a good choice as gratings for in-coupling applications.…”

“…For the production of liquid-crystal based polarization gratings two orthogonal circularly polarized beams are used and the resulting interference pattern is (in the paraxial approximation) linear everywhere. The direction of this linearity changes over a period from s-to p-and back to s-polarization [10,11]. This pattern can be recorded in a so-called linear photo-polymerizible polymer (LPP) [12,13].…”

“…When the angle between the recording beams becomes larger, corresponding to smaller grating periods, the paraxial approximation no longer holds. The interference pattern is then not completely constant in intensity and its polarization is slightly elliptical [11]. In this case it is assumed that the liquid crystal aligns with the long axis of the polarization ellipse.…”

A study on the optics of copper indium gallium (di)selenide (CIGS) solar cells with ultra-thin absorber layers

“…An in-house numerical code based on FEM is used to simulate the light interaction with the multilayer stack [5][6][7]. In brief, FEM solves a boundary value problem for the vector Helmholtz equation for either the electric or magnetic field in a confined computational domain.…”