scholarly journals A Fast-Response and Helicity-Dependent Lens Enabled by Micro-Patterned Dual-Frequency Liquid Crystals

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 111 ◽  
Author(s):  
Wei Duan ◽  
Peng Chen ◽  
Shi-Jun Ge ◽  
Xiao Liang ◽  
Wei Hu
Keyword(s):  
Liquid Crystals ◽  
High Efficiency ◽  
Switching Time ◽  
Berry Phase ◽  
Fast Response ◽  
Dual Frequency ◽  
Optical Elements ◽  
New Strategy ◽  
Patterning Technique ◽  
Liquid Crystal Lens

Liquid crystals are excellent candidates for tunable optical elements due to their large birefringence and continuous tunability by external fields. A dual-frequency liquid crystal lens integrated with Pancharatnam–Berry phase was fabricated via a dynamic photo-patterning technique. The proposed lens exhibited distinctive polarization-dependent characteristics and ultra-high efficiency rates of up to 95%. Via merely alternating the frequency of the applied electric field, the switching time between unfocused and focused states was measured in submilliseconds. This work supplies a new strategy for fast-response, high-efficiency and helicity-dependent lens with merits of easy fabrication and low power consumption.

scholarly journals Fast-response and high-efficiency optical switch based on dual-frequency liquid crystal polarization grating

2016 ◽  
Vol 6 (2) ◽  
pp. 597 ◽  
Author(s):  
Wei Duan ◽  
Peng Chen ◽  
Bing-Yan Wei ◽  
Shi-Jun Ge ◽  
Xiao Liang ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
High Efficiency ◽  
Optical Switch ◽  
Fast Response ◽  
Dual Frequency ◽  
Polarization Grating

scholarly journals Photo-Aligned Ferroelectric Liquid Crystal Devices with Novel Electro-Optic Characteristics

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 563
Author(s):  
Vladimir Chigrinov ◽  
Qi Guo ◽  
Aleksey Kudreyko
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Berry Phase ◽  
Photonic Devices ◽  
Ferroelectric Liquid Crystal ◽  
Optical Elements ◽  
Ferroelectric Liquid Crystals ◽  
Liquid Crystal Devices ◽  
Alignment Technique ◽  
Photo Alignment

This paper examines different applications of ferroelectric liquid crystal devices based on photo-alignment. Successful application of the photo-alignment technique is considered to be a critical breakthrough. A variety of display and photonic devices with azo dye aligned ferroelectric liquid crystals is presented: smart glasses, liquid crystal Pancharatnam–Berry phase optical elements, 2D/3D switchable lenses, and laser therapy devices. Comparison of electro-optical behavior of ferroelectric liquid crystals is described considering the performance of devices. This paper facilitates the optimization of device design, and broadens the possible applications in the display and photonic area.

scholarly journals High Efficient Metadevices for Terahertz Beam Shaping

2021 ◽  
Vol 9 ◽  
Author(s):  
Xinan Li ◽  
Zhixiong Shen ◽  
Qinggui Tan ◽  
Wei Hu
Keyword(s):  
High Performance ◽  
High Efficiency ◽  
Berry Phase ◽  
Vortex Generator ◽  
Maximum Efficiency ◽  
Optical Elements ◽  
Target Frequency ◽  
High Efficient ◽  
Pillar Arrays ◽  
Silicon Pillars

Metasurfaces supply a planar approach for flexible wavefront manipulation, thus facilitating the integration and minimization of optical elements, especially in the terahertz (THz) range. High efficient THz metadevices are highly pursued at present. Here, we propose a bilayer design to improve the efficiency of metadevice. Two silicon pillar arrays with distinguishing geometries are integrated on single silicon substrate. On one side, elliptical silicon pillars, with geometry optimized for the target frequency, are spatially orientated to realize the desired Pancharatnam-Berry phase. On the other side, uniform circular silicon pillars are set to suppress the reflection. With this design, versatile metadevices such as lens, lens array, polarization fork grating, Bessel vortex generator, and Airy beam generator are demonstrated. Maximum efficiency up to 95% for the target frequency and excellent design flexibility are verified. It provides a practical strategy for the generation of compact and high-efficiency THz metadevices, which suit for high-performance THz imaging and communication apparatuses.

scholarly journals Fast-response Pancharatnam-Berry phase optical elements based on polymer-stabilized liquid crystal

2019 ◽  
Vol 27 (16) ◽  
pp. 22522 ◽  
Author(s):  
Sida Li ◽  
Yueda Liu ◽  
Yan Li ◽  
Shuxin Liu ◽  
Shuyi Chen ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Berry Phase ◽  
Fast Response ◽  
Optical Elements ◽  
Polymer Stabilized

scholarly journals Recent progress in Pancharatnam–Berry phase optical elements and the applications for virtual/augmented realities

2017 ◽  
Vol 3 (1) ◽  
Author(s):  
Yun-Han Lee ◽  
Guanjun Tan ◽  
Tao Zhan ◽  
Yishi Weng ◽  
Guigeng Liu ◽  
...  
Keyword(s):  
Recent Progress ◽  
High Efficiency ◽  
Berry Phase ◽  
Large Angle ◽  
Beam Deflection ◽  
Optical Elements ◽  
Display Devices ◽  
Head Mounted Display ◽  
Fast Switching ◽  
Display Systems

AbstractIn this review paper,we report recent progress on Pancharatnam-Berry (PB) phase optical elements, such as lens, grating, and deflector. PB lenses exhibit a fast switching time between two or more focal lengths with large diopter change and aperture size, which is particularly attractive for addressing the accommodation mismatch in head-mounted display devices. On the other hand, PB gratings and deflectors offer a large-angle beam deflection with wide acceptance cone and high efficiency, as compared to conventional volume gratings. Such merits provide great advantages for waveguide-coupling augmented reality headsets. Moreover, the thickness of PB optical elements is only a few micrometers, thus they can be conveniently integrated into modern wearable display systems.

scholarly journals Enhancing the Optical Efficiency of Near-Eye Displays with Liquid Crystal Optics

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 107
Author(s):  
Tao Zhan ◽  
En-Lin Hsiang ◽  
Kun Li ◽  
Shin-Tson Wu
Keyword(s):  
Virtual Reality ◽  
Liquid Crystal ◽  
High Efficiency ◽  
Berry Phase ◽  
Optical Element ◽  
Liquid Crystal Polymer ◽  
Proof Of Concept ◽  
Optical Efficiency ◽  
Crystal Polymer ◽  
Light Efficiency

We demonstrate a light efficient virtual reality (VR) near-eye display (NED) design based on a directional display panel and a diffractive deflection film (DDF). The DDF was essentially a high-efficiency Pancharatnam-Berry phase optical element made of liquid crystal polymer. The essence of this design is directing most of the display light into the eyebox. The proposed method is applicable for both catadioptric and dioptric VR lenses. A proof-of-concept experiment was conducted with off-the-shelf optical parts, where the light efficiency was enhanced by more than 2 times.

scholarly journals Modified Levy Flight Optimization for a Maximum Power Point Tracking Algorithm under Partial Shading

2021 ◽  
Vol 11 (3) ◽  
pp. 992
Author(s):  
Chanuri Charin ◽  
Dahaman Ishak ◽  
Muhammad Ammirrul Atiqi Mohd Zainuri ◽  
Baharuddin Ismail
Keyword(s):  
High Efficiency ◽  
Energy System ◽  
Fast Response ◽  
Lévy Flight ◽  
Partial Shading ◽  
Levy Flight ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Steady State Oscillation ◽  
Power Point

This paper presents a novel modified Levy flight optimization for a photovoltaic PV solar energy system. Conventionally, the Perturb and Observe (P&O) algorithm has been widely deployed in most applications due to its simplicity and ease of implementation. However, P&O suffers from steady-state oscillation and stability, besides its failure in tracking the optimum power under partial shading conditions and fast irradiance changes. Therefore, a modified Levy flight optimization is proposed by incorporating a global search of beta parameters, which can significantly improve the tracking capability in local and global searches compared to the conventional methods. The proposed modified Levy flight optimization is verified with simulations and experiments under uniform, non-uniform, and dynamic conditions. All results prove the advantages of the proposed modified Levy flight optimization in extracting the optimal power with a fast response and high efficiency from the PV arrays.

scholarly journals New Methodology for Computing the Aircraft’s Position Based on the PPP Method in GPS and GLONASS Systems

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2525
Author(s):  
Kamil Krasuski ◽  
Damian Wierzbicki
Keyword(s):  
Linear Combination ◽  
Research Method ◽  
High Efficiency ◽  
Satellite System ◽  
Weighting Scheme ◽  
Measurement Technology ◽  
Dual Frequency ◽  
Weighted Mean ◽  
Mean Error ◽  
The Mean

In the field of air navigation, there is a constant pursuit for new navigation solutions for precise GNSS (Global Navigation Satellite System) positioning of aircraft. This study aims to present the results of research on the development of a new method for improving the performance of PPP (Precise Point Positioning) positioning in the GPS (Global Positioning System) and GLONASS (Globalnaja Nawigacionnaja Sputnikovaya Sistema) systems for air navigation. The research method is based on a linear combination of individual position solutions from the GPS and GLONASS systems. The paper shows a computational scheme based on the linear combination for geocentric XYZ coordinates of an aircraft. The algorithm of the new research method uses the weighted mean method to determine the resultant aircraft position. The research method was tested on GPS and GLONASS kinematic data from an airborne experiment carried out with a Seneca Piper PA34-200T aircraft at the Mielec airport. A dual-frequency dual-system GPS/GLONASS receiver was placed on-board the plane, which made it possible to record GNSS observations, which were then used to calculate the aircraft’s position in CSRS-PPP software. The calculated XYZ position coordinates from the CSRS-PPP software were then used in the weighted mean model’s developed optimization algorithm. The measurement weights are a function of the number of GPS and GLONASS satellites and the inverse of the mean error square. The obtained coordinates of aircraft from the research model were verified with the RTK-OTF solution. As a result of the research, the presented solution’s accuracy is better by 11–87% for the model with a weighting scheme as a function of the inverse of the mean error square. Moreover, using the XYZ position from the RTKLIB program, the research method’s accuracy increases from 45% to 82% for the model with a weighting scheme as a function of the inverse of the square of mean error. The developed method demonstrates high efficiency for improving the performance of GPS and GLONASS solutions for the PPP measurement technology in air navigation.

Order parameter of dual-frequency nematic liquid crystals measured over a wide range of thicknesses

2020 ◽  
Vol 47 (9) ◽  
pp. 1338-1344
Author(s):  
Olha Melnyk ◽  
Yuriy Garbovskiy ◽  
Anatoliy Glushchenko
Keyword(s):  
Liquid Crystals ◽  
Order Parameter ◽  
Nematic Liquid Crystals ◽  
Dual Frequency ◽  
Wide Range
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