Polarization properties of a nematic liquid-crystal spatial light modulator for phase modulation

Abstract

The polarization properties of a nematic zero-twist liquid-crystal (NLC) spatial light modulator (SLM) were studied. A large ratio between the liquid-crystal (LC) layer thickness and the pixel pitch combined with spatial variations in the applied electric field causes fringing fields between pixels. Depending on the LC alignment, the electric field components within the LC layer can result in a twist deformation. The produced inhomogeneous optical anisotropy affects the polarization of light propagating through the device. We experimentally examined polarization effects in different diffraction orders for both binary and blazed phase gratings. Simulations of the LC deformation together with finite-difference time-domain simulations for the optical propagation were used to calculate the corresponding far-field intensities. It was demonstrated how rigorous simulations of the NLC SLM properties can be used to understand the polarization features of different diffraction orders.

Accurate, Efficient and Rigorous Numerical Analysis of 3D H-PDLC Gratings

“…Wang et al [13] and Gui et al [14] also contributed to the analysis of H-PDLC using FDTD method for one-dimensionally periodic structures [13], and H-PDLC with embedded silver nanoparticles [14], respectively. It is also interesting to mention contributions more focused on the analysis of the properties of spatial light modulators based on a nematic zero-twist liquid-crystal (NLC); e.g., [15] computed the LC director by minimising the electric and elastic-free energies for one-dimensionally periodic structures, [16] analysed crosstalk in liquid spatial light modulators following a rigorous study of the LC director distribution as well and [17,18] followed a similar approach, also considering three-dimensional simulations and FDTD numerical method. The authors applied a two-dimensional split-field (SF) FDTD method to the analysis of ellipsoidal droplets in H-PDLC gratings with random properties [19].…”

Total Internal Reflection in a Hybrid Nematic Cell Submitted to Weak Boundary Conditions

“…In addition, they can be integrated into other optical components and compact systems [5]. Different types of optical elements based on liquid crystals technology have been implemented [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In particular, liquid crystal technology has been applied to construct diffraction gratings that can electrically modulate the diffraction efficiency [21].…”

On liquid crystal diffractive optical elements utilizing inhomogeneous alignment

“…Several types of LC optical elements have been proposed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The needed spatial distribution of the LC director is achieved in the majority cases by means of an inhomogeneous electric field [1][2][3][4][5][6][7][8][9][10][11][12] or with a thickness variations [1,2,13,14].…”

“…The needed spatial distribution of the LC director is achieved in the majority cases by means of an inhomogeneous electric field [1][2][3][4][5][6][7][8][9][10][11][12] or with a thickness variations [1,2,13,14]. Adaptation of such approaches for micron-scaled systems poses technological difficulties due to that electrodes are required or due to geometrical non-uniformities.…”