scholarly journals Two-Dimensional Digital Beam Steering Based on Liquid Crystal Phase Gratings

2021 ◽  
Vol 11 (8) ◽  
pp. 3632
Author(s):  
Mario García de Blas ◽  
Morten Andreas Geday ◽  
Jose Manuel Otón ◽  
Xabier Quintana Arregui
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Fill Factor ◽  
Pulse Width Modulation ◽  
Beam Steering ◽  
Active Area ◽  
Steering Angle ◽  
Direct Laser ◽  
Efficiency Map ◽  
Incoming Light

Electrically tunable phase gratings are able to steer an incoming light beam without employing movable parts. Here, we present the design and implementation of a 2D beam steering device by cascading two orthogonal 1D liquid crystal (LC) based phase gratings, each having an array of 72 rectangular individually controlled pixels and driven by a custom 12-bit Pulse-Width Modulation (PWM) electrical driver. High-resolution structures in glass wafers coated with transparent Indium-Tin Oxide (ITO) have been prepared using Direct Laser Writing (DLW) techniques. With DLW, a high number of pixels can easily be drawn with an interpixel space of less than 3 μm, leading to devices with a high fill factor. The active area of the cascaded device is 1.1 × 1.1 mm2. We present a 72 × 72 point efficiency map corresponding to a maximum diagonal steering angle of 1.65°. Special attention has been paid to make the device compatible with space application by avoiding electronics in the active area.

scholarly journals Liquid Crystal Devices for Beam Steering Applications

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 247
Author(s):  
Rowan Morris ◽  
Cliff Jones ◽  
Mamatha Nagaraj
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Adaptive Optics ◽  
Beam Steering ◽  
Optical Components ◽  
Advantages And Disadvantages ◽  
Liquid Crystal Devices

Liquid crystals are valuable materials for applications in beam steering devices. In this paper, an overview of the use of liquid crystals in the field of adaptive optics specifically for beam steering and lensing devices is presented. The paper introduces the properties of liquid crystals that have made them useful in this field followed by a more detailed discussion of specific liquid crystal devices that act as switchable optical components of refractive and diffractive types. The relative advantages and disadvantages of the different devices and techniques are summarised.

An investigation of the dynamic beam-steering capability of a liquid-crystal-enabled leaky-wave antenna designed for 5G applications

2021 ◽  
Vol 119 (3) ◽  
pp. 034104
Author(s):  
Rodrigue Tchema ◽  
Nectarios C. Papanicolaou ◽  
Anastasis C. Polycarpou
Keyword(s):  
Liquid Crystal ◽  
Beam Steering ◽  
Leaky Wave ◽  
Leaky Wave Antenna ◽  
Wave Antenna

scholarly journals Phase-only transmissive spatial light modulator based on tunable dielectric metasurface

Science ◽  
2019 ◽  
Vol 364 (6445) ◽  
pp. 1087-1090 ◽  
Author(s):  
Shi-Qiang Li ◽  
Xuewu Xu ◽  
Rasna Maruthiyodan Veetil ◽  
Vytautas Valuckas ◽  
Ramón Paniagua-Domínguez ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Light Modulator ◽  
Deflection Angle ◽  
Beam Steering ◽  
Beam Deflection ◽  
Spatial Light Modulators ◽  
Light Modulator ◽  
Steering Angle ◽  
Holographic Display ◽  
Light Modulators

Rapidly developing augmented reality, solid-state light detection and ranging (LIDAR), and holographic display technologies require spatial light modulators (SLMs) with high resolution and viewing angle to satisfy increasing customer demands. Performance of currently available SLMs is limited by their large pixel sizes on the order of several micrometers. Here, we propose a concept of tunable dielectric metasurfaces modulated by liquid crystal, which can provide abrupt phase change, thus enabling pixel-size miniaturization. We present a metasurface-based transmissive SLM, configured to generate active beam steering with >35% efficiency and a large beam deflection angle of 11°. The high resolution and steering angle obtained provide opportunities to develop the next generation of LIDAR and display technologies.

scholarly journals Fabrication of New Liquid Crystal Device Using Layer-by-Layer Thin Film Process

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 108 ◽  
Author(s):  
Gitae Moon ◽  
Wonjun Jang ◽  
Intae Son ◽  
Hyun Cho ◽  
Yong Park ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Indium Tin Oxide ◽  
Film Growth ◽  
Mechanical Stability ◽  
Liquid Crystal Display ◽  
Layer By Layer ◽  
Transparent Electrodes ◽  
Ito Electrode ◽  
Display Performance ◽  
Layer Thin Film

Indium tin oxide (ITO) transparent electrodes are troubled with high cost and poor mechanical stability. In this study, layer-by-layer (LBL)-processed thin films with single-walled carbon nanotubes (SWNTs) exhibited high transparency and electrical conductivity as a candidate for ITO replacement. The repetitive deposition of polycations and stabilized SWNTs with a negative surfactant exhibits sufficiently linear film growth and high optoelectronic performance to be used as transparent electrodes for vertically aligned (VA) liquid crystal display (LCD) cells. The LC molecules were uniformly aligned on the all of the prepared LBL electrodes. VA LCD cells with SWNT LBL electrodes exhibited voltage-transmittance (V-T) characteristics similar to those with the conventional ITO electrodes. Although the response speeds were slower than the LCD cell with the ITO electrode, as the SWNT layers increased, the display performance was closer to the LCD cells with conventional ITO electrode. This work demonstrated the good optoelectronic performance and alignment compatibility with LC molecules of the SWNT LBL assemblies, which are potential alternatives to ITO films as transparent electrodes for LCDs.

scholarly journals Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

2018 ◽  
Vol 9 ◽  
pp. 155-163 ◽  
Author(s):  
Doina Manaila Maximean ◽  
Octavian Danila ◽  
Pedro L Almeida ◽  
Constantin Paul Ganea
Keyword(s):  
Liquid Crystal ◽  
Cellulose Acetate ◽  
Indium Tin Oxide ◽  
Electric Energy ◽  
Equivalent Model ◽  
Electrical Characteristics ◽  
Impedance Measurements ◽  
Polymer Dispersed Liquid Crystals ◽  
Polymer Dispersed ◽  
Crystal Composite

Electro-optical devices that work in a similar fashion as PDLCs (polymer-dispersed liquid crystals), produced from cellulose acetate (CA) electrospun fibers deposited onto indium tin oxide coated glass and a nematic liquid crystal (E7), were studied. CA and the CA/liquid crystal composite were characterized by multiple investigation techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the dielectric loss with the Havriliak–Negami functions. To determine the electrical characteristics of the studied samples, impedance measurements results were treated using the Cole–Cole diagram and the three-element equivalent model.

Sign in / Sign up

Export Citation Format

Share Document