Liquid Crystal Digital Beam Steering Device Based on Decoupled Birefringent Deflector and Polarization Rotator

Abstract

We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises polarization rotator and birefringent prism deflector. We used prisms made of the uniaxial smectic A (SmA) liquid crystal and a solid yttrium orthovanadate crystal. SmA prisms have high birefringence and can be constructed in a variety of shapes. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by electrically switched twisted nematic or electrically controlled birefringent cell. We describe a four-stage DBD steering a normally incident laser beam within AE56 mrad range with 8 mrad steps.

Virtually image phased array based on Bragg reflector waveguide for large-port optical switching

“…A non-mechanical beam steering approach is useful for various applications where the beam direction changes rapidly to random locations or when a system needs to be compact with good mechanical stabilities. Various approaches for non-mechanical beam steering have been reported [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], which include an optical phased array, a liquid crystal phase modulator, an electro-optic crystal deflector, an in-plane laser array, a photonic crystal laser, a phase-locked VCSEL and so on. The beam steering performance can be figured by a number of resolution-points N, which is defined as distinguishable spot counts in far-field patterns.…”

Electrowetting actuated liquid prism with large steering angle based on additional gravitational effects

“…The other well‐known devices, like the acousto‐optic modulator and electro‐optic prism array within a polymer waveguide, have limited application due to the high cost and complicate mechanical design. Recently, some beam steering devices have been proposed based on the theory of liquid crystal and liquid, which mainly include electrophoresis and electrowetting . A high‐efficiency liquid‐crystal optical phased‐array beam steering has been demonstrated, but it is limited to the polarization‐dependence and energy absorption.…”

Agile wide-angle beam steering with electrowetting microprisms

“…These needs have fueled impressive development efforts in finding new approaches for beam steering. Alternative approaches now include acousto-optic [2] and electro-optic polymer [3] devices, decentered prisms and lenses [4,5], optical phased arrays based on dynamic liquid crystal gratings [6,7], and liquid crystal polarization rotators followed by multi-stage birefringent prisms [8,9]. Significant advances have now been made in key performance areas such as size, agility, and power.…”