Liquid crystals in dynamic holography (review)

Venediktov, Vladimir Yu.; Nevskaya, G. E.; Tomilin, M. G.

doi:10.1134/s0030400x11070216

Cited by 11 publications

(6 citation statements)

References 88 publications

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“…While it is possible to dynamically modify the phase and amplitude of light waves with the help of a spatial light modulator (SLM) 1 , 2 , it has proven challenging to similarly control sound waves. There exist a variety of methods to dynamically tune the phase and amplitude of light through techniques, including phase retardation in liquid crystals 3 , geometric-phase tuning via metasurfaces 4 , 5 , and binary switching of reflected amplitude via micro-electromechanical systems 6 . Acoustic waves possess no polarization and show no or little dispersion from the low audible kHz to the very high MHz ultrasound frequencies 7 , which considerably complicates the realization of a spatial modulator for sound waves analogous to an SLM.…”

Section: Introductionmentioning

confidence: 99%

Spatial ultrasound modulation by digitally controlling microbubble arrays

Melde

Athanassiadis

et al. 2020

Nat Commun

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Acoustic waves, capable of transmitting through optically opaque objects, have been widely used in biomedical imaging, industrial sensing and particle manipulation. High-fidelity wave front shaping is essential to further improve performance in these applications. An acoustic analog to the successful spatial light modulator (SLM) in optics would be highly desirable. To date there have been no techniques shown that provide effective and dynamic modulation of a sound wave and which also support scale-up to a high number of individually addressable pixels. In the present study, we introduce a dynamic spatial ultrasound modulator (SUM), which dynamically reshapes incident plane waves into complex acoustic images. Its transmission function is set with a digitally generated pattern of microbubbles controlled by a complementary metal–oxide–semiconductor (CMOS) chip, which results in a binary amplitude acoustic hologram. We employ this device to project sequentially changing acoustic images and demonstrate the first dynamic parallel assembly of microparticles using a SUM.

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Section: Introductionmentioning

confidence: 99%

Spatial ultrasound modulation by digitally controlling microbubble arrays

Melde

Athanassiadis

et al. 2020

Nat Commun

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“…Holographic patterning of liquid crystals and liquid crystalline polymers is a fairly well explored area and has been driven by the search for recording media suitable for optical data storage applications . This section aims to expose the reader to holographic LC “tools” capable of imparting or changing order in an LC on the scale of the wavelength of light, which can be used to drive color changes with light.…”

Section: Directed Self‐assembly Of Liquid Crystalline Materialsmentioning

confidence: 99%

“…In the static case, the gratings are retained after the writing beams are tuned off, until they are actively erased thermally (by heating the sample above the clearing temperature) or optically (by irradiation of light of a different wavelength to restore the azobenzene trans conformation or with light at the same wavelength as the writing beam but a different polarization state to restore the initial alignment). In the dynamic case, the state reached during the writing step is not stable and the system relaxes to its equilibrium uniform state when the writing beams are switched off . A few case studies are discussed in more detail here.…”

Section: Directed Self‐assembly Of Liquid Crystalline Materialsmentioning

confidence: 99%

Photoresponsive Structural Color in Liquid Crystalline Materials

McConney

Rumi

Godman

et al. 2019

Advanced Optical Materials

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and then impinging on our eyes. Our brain, rightly or wrongly, interprets these and other sensed patterns as reality. Hence, the saying, "seeing is believing."Given that much of our perceived reality is the result of light-matter interactions, it is no surprise that humans have been actively pursuing methods to understand and control the appearance of materials for thousands of years. Through mixing natural dyes of primary colors, people were able to tailor the color of everyday objects by changing their spectral absorption. The science of absorption-based colored materials evolved to the point of creating materials with light-responsive absorption (photochromics) that, when combined with a camera, were used to capture scenes, thereby allowing us to recreate and share moments of reality. Despite huge advances in the ability to control objects' absorptive color over the last 200 years through chemistry, controlling objects' structural color is still quite challenging. Structural color often refers to spectral interference effects associated with periodic spatial changes in the refractive index of materials (sometimes referred to as photonic crystals). These socalled photonic materials are a unique class of materials that have the ability to strongly affect the light-matter interactions for wavelengths on the scale of the refractive index periodicity. Photonic materials have particularly vivid colors that emerge from their angularly sensitive spectral reflections. Some of the early studies in this area were performed on natural photonic materials that caught the eye of curious scientists. [1] There are many examples of naturally occurring self-assembled photonic materials, including opals, [2] Pollia fruit, [3] jeweled beetles, [1,4] chameleons, [5] and others. [6] These natural examples of structurally derived color can be emulated, altered, or reproduced by researchers. [7][8][9] The ability of biology to self-assemble materials with complex structures and functionality is still unrivaled by engineered systems, but unique opportunities now exist for major advances in autonomously adaptive materials, as scientists are deciphering the molecular mechanisms that biology uses to self-assemble amazingly complex adaptive systems. [10] Particularly relevant to this review, some of the photonic structures found in nature are able to change periodicity in Photoresponsive liquid crystalline photonic materials are a medium in which the self-regulation of light can occur. Liquid crystals are macroscopically selfassembling, optically anisotropic materials capable of amplifying photochemical changes and thus are well suited to demonstrate complex light-driven behavior. This review presents recent progress in liquid crystalline systems exhibiting photoresponsive structural color. More specifically, it surveys progress on liquid crystalline materials and structures with coloration that is the result of the constituents' spatial arrangement (not of presence of dyes or pigments) and for which this arrangement can be externally cont...

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“…Одной из важных научно-практических задач современных систем фотоники является необходимость формирования световых полей с заданными пространственными характеристиками [1,2]. С изобретением пространственных модуляторов света (ПМС) появилась возможность для оперативной модуляции амплитуды или фазы светового поля, что имеет особое значение для получения различных световых распределений [3,4].…”

Section: Introductionunclassified

Определение Функции Рассеяния Точки Компьютерно-Синтезированной Линзы, Сформированной Фазовым Модулятором Света

Сцепуро¹,

Красин²,

Ковалев³

et al. 2020

Журнал Технической Физики

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In various areas of photonics, there is a tendency to move from elements of physical optics to elements of flat optics, primarily due to reducing dimensions of instruments and devices. Usually, spatial light modulators are used to quickly output flat phase elements. In this paper, the possibility of replacing the optical system with a computer-generated lens was investigated. The novelty of the work lies in a comparative analysis of point spread functions formed by an optical system and a computer-synthesized lens. Numerous experiments confirm the result.

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Liquid crystals in dynamic holography (review)

Cited by 11 publications

References 88 publications

Spatial ultrasound modulation by digitally controlling microbubble arrays

Spatial ultrasound modulation by digitally controlling microbubble arrays

Photoresponsive Structural Color in Liquid Crystalline Materials

Определение Функции Рассеяния Точки Компьютерно-Синтезированной Линзы, Сформированной Фазовым Модулятором Света

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