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 Photovoltaic Concentration: Research and Development

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5721
Author(s):  
Sarah El Himer ◽  
Salima El Ayane ◽  
Sara El Yahyaoui ◽  
Jean Paul Salvestrini ◽  
Ali Ahaitouf
Keyword(s):  
Energy Source ◽  
Solar Cells ◽  
Research And Development ◽  
Concentration Ratio ◽  
Recent Progress ◽  
High Efficiency ◽  
Cost Effective ◽  
Optical Elements ◽  
Concise Overview

Concentrator Photovoltaic (CPV) technology, by using efficient optical elements, small sizes and high efficiency multi-junction solar cells, can be seen as a bright energy source to produce more cost-effective electricity. The main and basic idea is to replace the use of expensive solar cells with less expensive optical elements made from different materials. This paper aims to give to the readers a rapid and concise overview of CPV and the main characteristics to be considered when designing a CPV system. It reviews the main optical configurations presented in the literature, their advantages and drawbacks, as well as the recent progress in the concentration ratio and the major performances achieved in the field. The paper considers the more recent works, their optical designs, as well as their optical and electrical performances. It also relates the major achievements on the industrial side with the major milestones in CPV developments.

scholarly journals Diffractive Optical Elements with a Large Angle of Operation Recorded in Acrylamide Based Photopolymer on Flexible Substrates

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hoda Akbari ◽  
Izabela Naydenova ◽  
Lina Persechini ◽  
Sean M. Garner ◽  
Pat Cimo ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
High Efficiency ◽  
Large Angle ◽  
Optical Recording ◽  
Holographic Recording ◽  
Angular Range ◽  
Optical Elements ◽  
Lens Element ◽  
Single Lens ◽  
Exposure Energy

A holographic device characterised by a large angular range of operation is under development. The aim of this study is to increase the angular working range of the diffractive lens by stacking three layers of high efficiency optical elements on top of each other so that light is collected (and focussed) from a broader range of angles. The angular range of each individual lens element is important, and work has already been done in an acrylamide-based photosensitive polymer to broaden the angular range of individual elements using holographic recording at a low spatial frequency. This paper reports new results on the angular selectivity of stacked diffractive lenses. A working range of 12° is achieved. The diffractive focussing elements were recorded holographically with a central spatial frequency of 300 l/mm using exposure energy of 60 mJ/cm2at a range of recording angles. At this spatial frequency with layers of thickness 50 ± 5 µm, a diffraction efficiency of 80% and 50% was achieved in the single lens element and combined device, respectively. The optical recording process and the properties of the multilayer structure are described and discussed. Holographic recording of a single lens element is also successfully demonstrated on a flexible glass substrate (Corning(R) Willow(R) Glass) for the first time.

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 Miniature planar telescopes for efficient, wide-angle, high-precision beam steering

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ziqian He ◽  
Kun Yin ◽  
Shin-Tson Wu
Keyword(s):  
Liquid Crystal ◽  
Optical Tweezers ◽  
High Precision ◽  
High Efficiency ◽  
Low Cost ◽  
Beam Steering ◽  
Large Angle ◽  
High Quality ◽  
Optical Elements ◽  
Optical Efficiency

AbstractNon-mechanical beam steerers with lightweight, compact, high-efficiency, high-precision, and/or large-angle are pivotal for light detection and ranging (LiDAR) of autonomous vehicles, eye-tracking for near-eye displays, microscopy, optical tweezers, and high-precision three-dimensional (3D) printing. However, even the most matured optical phased array can only provide quasi-continuous, efficient beam steering within a small angle range. A telescope module with an angle magnification function can be coupled to enlarge the steering range or precision. But obtaining a compact, low-cost, lightweight, high-quality telescope module with conventional optics remains challenging. Patterned liquid crystal-based planar optical elements offer great design freedom for manipulating the phase profile of light in 2D space. Owing to the advantages of high efficiency, thinness, low cost, easy processing, flexibility, and response to environmental stimuli, a plethora of high-quality optical devices have been demonstrated. Here, a miniature planar telescope mediated by liquid crystal polymers is proposed to offer angle magnification independent of incident spatial location. It consists of two cascaded liquid crystal planar optical elements, each performing a predefined mathematical transformation. By this concept, planar optical elements are fabricated using a new exposure method and assembled into planar telescopes with different magnification factors. Within the incident field range, over 84.6% optical efficiency is achieved with small wavefront distortion. Such a miniature planar telescope shows the potential of cascaded liquid crystal planar optical elements for realizing functionalities that cannot be fulfilled by single optical elements, and enables lightweight, low loss, passive optical transmitters for widespread applications.

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 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.

Large-angle beam deflection of a laser-cooled sodium beam

1989 ◽  
Vol 6 (11) ◽  
pp. 2149 ◽  
Author(s):  
J. Nellessen ◽  
J. H. Müller ◽  
K. Sengstock ◽  
W. Ertmer
Keyword(s):  
Large Angle ◽  
Beam Deflection ◽  
Sodium Beam

Recent progress of high efficiency white LEDs

2007 ◽  
Vol 204 (6) ◽  
pp. 2087-2093 ◽  
Author(s):  
Yukio Narukawa ◽  
Junya Narita ◽  
Takahiko Sakamoto ◽  
Takao Yamada ◽  
Hiroki Narimatsu ◽  
...  
Keyword(s):  
Recent Progress ◽  
High Efficiency ◽  
White Leds

Recent progress of Spectrolab high-efficiency space solar cells

2012 ◽  
Author(s):  
Daniel C. Law ◽  
X.Q. Liu ◽  
J.C. Boisvert ◽  
E.M. Redher ◽  
C.M. Fetzer ◽  
...  
Keyword(s):  
Solar Cells ◽  
Recent Progress ◽  
High Efficiency

scholarly journals Metalenses Based on Symmetric Slab Waveguide and c-TiO2: Efficient Polarization-Insensitive Focusing at Visible Wavelengths

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 699 ◽  
Author(s):  
Yaoyao Liang ◽  
Zhongchao Wei ◽  
Jianping Guo ◽  
Faqiang Wang ◽  
Hongyun Meng ◽  
...  
Keyword(s):  
Berry Phase ◽  
Incident Light ◽  
Visible Spectrum ◽  
Slab Waveguide ◽  
Optical Elements ◽  
Polarization Insensitive ◽  
Wavefront Shaping ◽  
Visible Wavelengths ◽  
532 Nm ◽  
Good Agreement

A key goal of metalens research is to achieve wavefront shaping of light using optical elements with thicknesses on the order of the wavelength. Here we demonstrate ultrathin highly efficient crystalline titanium dioxide metalenses at blue, green, and red wavelengths (λ0 = 453 nm, 532 nm, and 633 nm, respectively) based on symmetric slab waveguide theory. These metalenses are less than 488 nm-thick and capable of focusing incident light into very symmetric diffraction-limited spots with strehl ratio and efficiency as high as 0.96 and 83%, respectively. Further quantitative characterizations about metalenses’ peak focusing intensities and focal spot sizes show good agreement with theoretical calculation. Besides, the metalenses suffer only about 10% chromatic deviation from the ideal spots in visible spectrum. In contrast with Pancharatnam–Berry phase mechanism, which limit their incident light at circular polarization, the proposed method enables metalenses polarization-insensitive to incident light.

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