Barma Daria

30 Liquid Crystals, metasurfaces terms

[1] - Xiao Xiang, Jihwan Kim & Michael J. Escuti. Bragg polarization gratings for wide angular bandwidth and high efficiency at steep defection angles // Scientific Reports. 2018. (2018) 8:7202 | DOI:10.1038/s41598-018-25535-0 [2] - Xiao Xiang et al. Nanoscale liquid crystal polymer Bragg polarization gratings // Optics Express. 2017. Vol. 25. № 16. Р. 19298. [3] - Maxim V. Gorkunov*, Irina V. Kasyanova, Vladimir V. Artemov, Alexander A. Ezhov, Alena V. Mamonova, Ivan V. Simdyankin, and Serguei P. Palto. Liquid-Crystal Metasurfaces Self-Assembled on Focused Ion Beam Patterned Polymer Layers: Electro-Optical Control of Light Diffraction and Transmission // Applied Materials. 2020, 12, 27, 30815-30823. DOI: 10.1021/acsami.0c07320. [4] - Shiyuan Zhang, Wan Chen, Yang Yu, Qidong Wang, Quanquan Mu, Shixiao Li and Jin Chen. Twisting Structures in Liquid Crystal Polarization Gratings and Lenses // Crystals 2021. 11. 243⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ Phrases: As mentioned in previous work [1]⠀⠀⠀⠀ Right-hand circular polarization [1]⠀⠀⠀⠀ As detailed previously [1]⠀⠀⠀⠀ This element maintains high frst-order efficiency, widespectral bandwidth, and strong polarization sensitivity. [1]⠀⠀⠀⠀ Multiple twisted nematic layers [1]⠀⠀⠀⠀ As detailed previously [1]⠀⠀⠀⠀ Quartz quaterwave plate [1]⠀⠀⠀⠀ Polarization Gratings (PGs) are diffractive optical elements comprising an in-plane anisotropy orientation that varies linearly along a Surface, with a fixed anisotropy magnitude. [2]⠀⠀⠀⠀ Experimentally demonstrated efficiency approaching [2]⠀⠀⠀⠀ Classical grating analysis distinguishes Raman-Nath (thin) from Bragg (thick) grating regimes [2]⠀⠀⠀⠀ Note that in our convention [1] Femtosecond laser pulses [3]⠀⠀⠀ This effect may be related to [2]⠀⠀⠀ Strongly selective to input polarization [2]⠀⠀⠀⠀⠀ Augmented-reality systems [2]⠀⠀ Metasurfaces with liquid crystals [3]⠀⠀ LC-based devices [3]⠀ Focusedion-beam (FIB) patterning [3] Scattering of light [3] Plasmon resonances of metallic structures [3]⠀⠀ Sophisticated solid-state nanostructures [3] ⠀⠀ Dye-doped polymer films [3] ⠀⠀ Digitally controlled technique [3] ⠀⠀ Superperiodic LC metasurfaces [3] ⠀⠀ One can employ [3]⠀⠀ Liquid crystal polarization gratings [4]⠀⠀ Twisting structures forming Bragg diffraction [4]⠀⠀ Multi-layer twisting structure [4]⠀⠀ Full-color displays [4]

Angular bandwidth
The angle of diffraction that contain all diffraction orders.
Example: More specifcally, we demonstrate a liquid crystal (LC) polymer Bragg polarization grating (PG) with large angular bandwidth and high efciency in transmission-mode for 532nm wavelength and 400nm period. [1]
en: Угловое поле
Augmented-reality
The space created by superimposing a picture from the display on the image of the surrounding world
Example: This approach is especially advantageous for augmented-reality systems and nonmechanical beam steering. [1]
en: Дополненная реальность
Beam-steering
Setting the selected direction for the light propogation using optical components.
Example: One approach uses various types of transmission-mode difraction gratings with periods near or below the wavelength of operation, which are particularly useful in waveguide-based head-mounted-displays and nonmechanical beam-steering. [1]
en: Управление лучом света
Birefringence
It is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light.
Example: Short-wavelength circular birefringence region (SW-CBR): In this region (λ < P), the eigenmodes are elliptically polarized with the opposite handedness. [4]
en: Двулучепреломление
Bragg difraction
It is a condition or Laue-Bragg interference, a special case of Laue diffraction, gives the angles for coherent scattering of waves from a crystal lattice.
Example: Bragg difraction can be established when \lambda_B meets the condition of the incident wvelenght and LC layer is thick enough to generate enough periodical refractive index planes. [4]
en: Дифракция Брэгга
Bulk
Something very large, or a large amount, not divided into smaller parts.
Example: Being determined by reorientation of small adjacent LC volumes, such tuning can be much faster than the switching of LC bulk, allows reducing the LC-cell thickness and building micrometer-sized pixels. [3]
en: Объем (про жидкие кристаллы)
Diffraction grating
Optical device, the operation of with is based on the light interference. This can be a set of diffracting elements, such as a pattern of transparent slits or holes in an opaque screen, or a set of reflective grooves on the substrate.
Example: One approach uses various types of transmission mode difraction gratings with periods near or below the wavelength of operation, which are particularly useful in waveguide-based head-mounted-displays and nonmechanical beam-steering. [1]
en: Дифракционные решетки
Film
A thin layer of something on a surface
Example: Tis was achieved by layering two slants within the same LC polymer Bragg PG monolithic flm. [2]
en: Пленка
Helical axis
The axis along which the molecules are twisted in a spiral.
Example: Note that the LC is still in a nematic phase in each plane (x-y plane) perpendicular to the helical axis (z axis), which could be regarded as a uniaxial crystal. [4]
en: Ось спирали
Helical pitch
Distance in which the orientation of LC molecules rotated 360 degrees.
Example: The helical pitch P was defined as the distance in which the orientation of LC molecules rotated 360 degrees. [4]
en: Сила закрутки
Ion-beam
It is a type of charged particle beam consisting of ions.
Example: It has been demonstrated that using focusedion-beam (FIB) patterning of rubbed polyimide (PI) films one can produce interfaces lacking pronounced relief or own photonic properties but inducing spatially modulated nematic LC alignment.
en: Ионный пучок
Media
It is a region of space having a limited configuration and a certain refractive index
Example: The transmittance, defined as Tm = Pm/Pin, is nearly the same efficiency in our case, because the primary loss is the air-glass interfaces (about 5% each), and lower losses between the various glass, glue, and oil media. [2]
en: Среда
Metasurface
А special structure that allows to obtain various optical components on flat glass substrates.
Example: Optical liquid-crystal metasurfaces self-assemble on polymer layers locally processed with a digitally controlled focused ion beam. [3]
en: Метаповерхности
Nanostructure
It is a structure of intermediate size between microscopic and molecular structures.
Example: Recently, we have proposed to employ the metasurface concept for creating nonresonant broadband functional optical elements entirely consisting of LCs, eluding sophisticated solid-state nanostructures. [3]
en: Наноструктура
Photo-alignment layer
The layer of a dye or a polymer forming diffraction pattern upon Van der Vaals forces
Example: Using photo-alignmentpolymers and high-birefringence LC materials, we employ multiple thin sublayers to overcome the critical thickness threshold, and use chiral dopants to induce a helical twist that effectively generates a slanted grating. [2]
en: Фото-ориентирующий слой
Polarization
The act of making light waves move in one direction only, or mainly in one direction
Example: Similar to the prior one-slant nanoscale Bragg PG work, it was strongly selective to input polarization (300:1 contrast), and the output polarization of the frst-order varied from linear to circular, depending on incidence angle. [1]
en: Поляризация
Polarization sensitivity
The ratio of the difference between the maximum and minimum intensity of interference to their sum
Example: Strong input polarization sensitivity (300:1 contrast) and spectral bandwidth (200nm) mostly matched prior PGs. [1]
en: Поляризационная чувствительность
Polarizer
It is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations.
Example: From the practical point, compared to conventional LC-based devices, the performance of such hybrids is not always impressive: simple replacement of conventional polarizers and filters with sophisticated nanostructures drastically increases the complexity but does not automatically grant new performance features. [3]
en: Поляризатор
Refraction
It is the change in direction of a wave passing from one medium to another or from a gradual change in the medium.
Example: We experimentally implement and test the designs by fabricating the LC metasurfaces as described in Fabrication and demonstrating in Transmission and Diffraction Properties that they indeed exhibit strongly asymmetric diffraction leading to effective anomalous refraction. [3]
en: Преломление
Refractive index
It is a dimensionless number that describes how fast light travels through the material.
Example: These refractive index surfaces constitute a periodicity ΛB: ΛB = Λx sin ψ = Λy cos ψ, (3) in a slanted dimension and, by different given ΛB values, the diffraction behavior of the grating changes obviously. [4]
en: Показатель преломления
Resonance
Resonance describes the phenomenon of increased amplitude that occurs when the frequency of a periodically applied force is equal or close to a natural frequency of the system on which it acts.
Example: Qualitative improvements have been achieved by utilizing the LC environment for tuning the electromagnetic resonances hosted by metasurface elements plasmon resonances of metallic structures and Mie-type resonances of dielectric particles. [3]
en: Резонанс
Retarder
It is an optical device that alters the polarization state of a light wave travelling through it.
Example: Note that broadband polarization transformation could be achieved through additional degrees of freedom arising from using multiple uniaxial retarders, whose optical axis varies discretely through the compound structure. [4]
en: Замедлитель
Sample
a small amount of something that shows you what the rest is or should be like
Example: We also measured the spectral response of the zero-order for two samples with a spectrophotometer, and estimated the first-order efficiency. [2]
en: Образец
Slant
The direction in which the molecules are located in the thickness of the lcd volume
Example: It is possible to use three or more slants, e.g., to enable even wider angular bandwidths and achieve angular response shapes diferent than a fat-top. [1]
en: Угол преднаклона
Thickness
Geometrical thickness times its intensity attenuation coefficient.
Example: Besides, we can also control the thickness of each layer by spin-coating to avoid the deterioration of LC alignment and device quality caused by exeeding the critical thickness. [4]
en: Толщина
Total-internal-reflection
The case for light passing the interface when the light is only reflected inside the first medium
Example: Finally, we measured what occurs when total-internal-reflection (TIR) causes the first-order to reflect back onto the same grating multiple times. [2]
en: Полное внутреннее отражение
Transmission-mode
Tranmission mode defines the direction of the flow of information between two communication devices.
Example: More specifcally, we demonstrate a liquid crystal (LC) polymer Bragg polarization grating (PG) with large angular bandwidth and high efficiency in transmission-mode for 532nm wavelength and 400nm period. [1]
en: Мода пропускания
Twisting structure
The structure in which the chiral dopant interacts with the liquid crystal is oriented in a spiral.
Example: Based on phase compensation, Oh et al. [19,22,23] have proved that the dual-twist structure can broaden the bandwidth of high diffraction efficiency, and Li Tan [15,24,25] has also confirmed that a twisting structure can also provide certain compensation in terms of view angle. [4]
en: Спиральная структура
Wavelength
The distance between two waves of energy, or the length of the radio wave used by a particular radio station for broadcasting programs
Example: Specifcally, this grating with 400 nm period measured at 532 nm wavelength manifest in experiment a 40° angular bandwidth, 200 nm spectral bandwidth, 76% average efciency, and 96% peak efciency. [1]
en: Длина волны излучения
Waveplate
It is an optical device that alters the polarization state of a light wave travelling through it.
Example: Although being limited by the scale and available types of such patterns, the technique enabled creating an impressive range of LC-based devices: diffraction gratings, lenses, q-plates, diffractive waveplates, and even holographic images. [3]
en: Волновая плоскость