Nune Hakobyan

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Verified

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• Master of Engineering
• Researcher at Yerevan State University

THz technology is a rapidly advancing field in both fundamental and applied research, integrating novel approaches from optical and microwave ranges. Despite the wide applications of liquid crystals (LCs) in the visible range, their efficiency in the THz range is limited due to the low optical path length of existing anisotropic LC materials. In th...

The interaction of liquid crystal (LC) fork-like gratings (FLGs) with a Laguerre–Gaussian beam of the TEM00 mode is described. It is experimentally shown that when the direction of the light polarization vector differs from the direction of the LC eigenvectors, the medium behaves as an FLG with a controlled modulation depth, and in the opposite cas...

Driving a position of light beam, i.e. light beam steering, is a rapidly growing branch of adaptive optics with applications such as light detection and ranging, imaging, optical communications, and atomic physics. For spatial scanning of light, dielectric transparent matrices with variable refractive index with quantum dots can be used as active...

Liquid crystals have emerged as promising materials in the field of modern optics and photonics. Their unique properties make them promising for various applications, including light beam shaping and the generation of optical vortices characterized by orbital angular momentum. Cholesteric liquid crystals (CLCs) possess a spiral supramolecular struc...

Apparatus for filling liquid crystal device with liquid crystal substance

In this work, we systematically analysed the THz properties of pyrolytic carbon (PyC)/liquid crystal (LC) cell in THz frequency range of 0.2 THz to 1.2 THz, which is provided by means of THz time domain spectroscopy. PyC film realizes the electrode function in this cell. Due to possibility of controlling the thickness of PyC films during synthesis,...

Описан жидкокристаллический управляемый оптический фильтр для видимой и ближней инфракрасной областей спектра, комбинируемый с устройствами видеонаблюдения, работающий в широком интервале температур. Рассмотрены конфигурации фильтра с использованием жидкокристаллических ячеек с твист, гомеотропной и планарной ориентациями. Показано, что характерное...

Ориентированные жидкокристаллические ячейки в скрещенных поляризаторах имеют однородный вид без приложения электрического поля. Но при приложении напряжения может наблюдаться мозаичная текстура с участками различной ориентации молекул ЖК. Плавное и последовательное передвижение образовавшегося в процессе изготовления ячейки воздушного пузыря позвол...

RESULTS A temperature setting and stabilization unit based on Peltier elements (Figure 8), allowing the testing of LC devices in the temperature range of-25 0 C ÷ 40 0 C is developed. The use of this unit in conjunction with the "LC Driver" device will ensure the testing of the LC cell in various temperature conditions and expand the range of inves...

The liquid crystal (LC) cells with planar orientation have been investigated. The inner surfaces of the substrates were coated with a layer of a photo-orienting polymer and the planar orientation was recorded by polarized laser radiation at a wavelength of 325 nm. The cell has a uniform appearance without applying voltage. But when a voltage is app...

Photoalignment on azo dye films is a simple and efficient way to achieve anisotropic ordering of molecules, which is promising to achieve ultra-thin high-performance dichroic polarizers. Besides, the photoalignment technique shows a unique advantage on patterned alignment applications, and enables the realization of advanced optical elements such a...

The diffraction of polarized light transmitted through an optically anisotropic substrate with surface microrelief is calculated using the Exedeep program (optically anisotropic lattices with surface microrelief). The diffraction parameters are determined in different diffraction orders of transmitted and reflected TE and TM waves for materials wit...

The manufacturing technique of a millimetric sizes cantilever from photo-driven azobenzene polymer is described. The cantilever oscillations under the influence of laser radiation are studied. The possibility of making a micron-sized cantilever by a femtosecond laser initiated two-photon polymerization technique is shown. Such cantilever can become...

Diffraction optical elements (DOE) are important elements of systems for images displaying and processing. The DOE materials with both positive and negative birefringence enhance performances and functionality of such systems. We have calculated the diffraction of rays passing through optically anisotropic grating with surface microrelief by using...

Diffraction optical elements (DOE) are important elements of systems for images displaying and processing. The DOE materials with both positive and negative birefringence enhance performances and functionality of such systems. We have calculated diffraction of rays passing through (OAGSM) by using our original Exedeep software. At the first time th...

The synthesis of new photo-orienting liquid crystal polymers made it possible to create a completely new type of optical elements consisting of ultrathin layers with a spatially structured orientation of the optical axis. In this paper the optical elements based on centrally symmetric periodic structures with cylindrical orientations of molecules a...

Circular dichroism (CD) is an important parameter, characterizing optically active medium. The devices for CD measurements presented on today market measures CD in wide spectral range. The high‐precision standard optics, electronics and optomechanics are used in these devices, and data processing requires the application of a complex mathematical a...

On-line presentation of CD METER - Device for measuring of circular dichroism at one specific wavelength.

Liquid crystal (LC) director and refractive index distribution in a cylindrical object (eg, micropore) with different LC boundary conditions have been simulated. Splay and bend configurations were simulated in the LC pores with Franck elastic coefficients K 33 /K 11 ratio from 0.5 to 3. For different LC orientation configurations, parabolic profile...

We show the opportunity to fabricate a device for measuring circular dichroism (CD) in real time, the key element of which is a liquid crystal cycloidal diffractive waveplate (CDW). We present the results of simulations carried out to estimate the accuracy of CD spectrum measurement using CDW. We pay attention to the fact that, using two charge-cou...

A technique for recording a matrix of ring-shaped microstructures due to the postpolymerization of an already oriented layer of liquid crystal polymer under the influence of a focused intensive light radiation is developed. Using this technique, a microstructures matrix patterned element is realized. The reorientation process of the microstructure...

1. Введение Недавно синтезированные жидкокристаллические (ЖК) полимеры [1], со-четающие двулучепреломление жидких кристаллов с механическими свой-ствами полимеров, в силу своих уникальных свойств позволили создать оптические элементы нового поколения с применением различных методов оп-тической записи. На основе этих материалов были созданы не тольк...

In liquid crystal devices (LCDs) the indium tin oxide (ITO) films are traditionally used as transparent and conductive electrodes. However, today, due to the development of multichannel optical communication, the need for flexible LCDs and multilayer structures has grown. For this application ITO films cannot be used in principle. For this problem,...

A technique is developed for recording the centrally-symmetric liquid crystal phase plates with the anisotropic orientation of molecules providing a smooth change of the optical axis in a thin film of liquid crystal polymer. The technique enables one to record the elements with the cylindrically-symmetric and planar-symmetric distributions. Such st...

Methods based on optical activity measurement, are widely used in physical, chemical, biological researches and in industry. Purely technical difficulties in CD measuring have been overcome only recently, so CD method can be considered as new. Devices for CD measuring, presented in today market, are high-precision, expensive and are intended only f...

Graphene is only one atom thick, optically transparent, chemically inert, and an excellent conductor. These properties seem to make this material an excellent candidate for applications in various photonic devices that require conducting transparent thin films. In this work the electrooptical and dynamic characteristics of liquid crystal (LC) cell...

Circular dichroism (CD) is an important parameter, characterizing optically active medium. The devices for CD measurements presented on today market measures CD in wide spectral range. The high-precision standard optics, electronics and optomechanics are used in these devices, and data processing requires the application of a complex mathematical a...

Разработана техника записи центросимметричных жидкокристаллических фазовых пластин с анизотропной ориентацией молекул, обеспечивающая плавное изменение оптической оси в тонкой пленке жидкокристаллического полимера. Методика позволяет записать элементы с цилиндрически-симметричным и планарно симметричным распределениями. Такие структуры можно исполь...

We propose new controllable LC-composite diffractive optical elements based on a new phenomenon of forming LC microfilaments with a length of up to several centimeters in a borosiloxane matrix. Materials based on the investigated LC composites can be used in display technology and optoelectronics, for example, as microresonators and electron-optica...

Գյուտը վերաբերում է օպտիկայի ոլորտին, մասնավորապես՝ հեղուկ բյուրեղային պոլիմերների հիման վրա կենտրոնահամաչափ բևեռային դիֆրակցիոն ալիքային թիթեղի ստեղծմանը և դրա պատրաստման եղանակի մշակմանը, և կարող է կիրառվել օպտիկական սարքաշինության մեջ: Հեղուկ բյուրեղային բևեռային դիֆրակցիոն ալիքային թիթեղը պատրաստվում է ֆոտոկողմնորոշվող նյութով պատված շրջանաձև հ...

Գյուտը վերաբերվում է բժշկական սարքաշինության ոլորտին, մասնավորապես՝ ոչ ինվազիվ եղանակով մարդու օրգանիզմում գլյուկոզայի պարունակությունը որոշելու համար օպտիկական սարքի մշակմանը և կարող է կիրառվել բժշկական սարքաշինության մեջ: Առաջարկվում է ոչ ինվազիվ եղանակով գլյուկոզայի պարունակության որոշման համար նախատեսված պարզ սարք, որում օգտագործվում են միայն օ...

The invention refers to medical equipment, in particular, to optical device development for non-invasive determination of glucose concentration in human organism and it can be applied in medical equipment industry. A simple device for non-invasive determination of glucose concentration is offered, in which only the optical elements are used. The de...

Technique for real-time spectropolarimetry is developed. An embedded system for circular dichroism registration is designed based on National Instruments single board reconfigurable I/O platform for ultraviolet and visible spectroscopic needs. The basic functional unit of the proposed device is liquid crystal polarization diffraction grating. In or...

Invention relates to development of centrally symmetric liquid crystal polarization diffraction waveplate (LC CDW) and its fabrication method. In the created optical element the ordering of LC molecules directors along each radius corresponds to axial LC polarization diffraction grating (PDG), and in two PDGs recorded along one diameter, the orderi...

The invention refers to optics, in particular to the development of a new method for optical measurements. Possible fields of the invention application are: polarimetry, spectropolarimetry and ellipsometry. The invention proposes a method for registration of changes in monochromatic light beam polarization, based on using of axial symmetric liquid...

The invention refers to optics, in particular to the development of a new method for optical measurements. Possible fields of the invention application are: polarimetry, spectropolarimetry and ellipsometry. The invention proposes a method for registration of changes in monochromatic light beam polarization, based on using an axial symmetric liquid...

Разработана конечно-разностная численная (FDTD) модель жидкокри-сталлической дифракционной фазовой решетки и показана возможность ис-пользования данной решетки для пространственно-временного управления из-лучением в среднем инфракрасном диапазоне длин волн.

The numerical finite difference time domain (FDTD) model of liquid crystal diffraction phase grating is developed and the possibility to use this grating for the spatial-time control of radiation in the mid IR wavelength range is shown.

Գյուտը վերաբերում է օպտիկական սարքաշինության ոլորտին, 5 մասնավորապես՝ լայն սպեկտրալ տիրույթում շրջանային դիքրոիզմի (այսուհետև՝ ՇԴ) գրանցման համար նախատեսված սպեկտրաբևեռաչափի մշակմանը և կարող է կիրառվել օպտիկական սարքաշինության մեջ:

Գյուտը վերաբերում է օպտիկական սարքաշինության ոլորտին, մասնավորապես՝ լայն սպեկտրալ տիրույթում շրջանային դիքրոիզմի գրանցման համար նախատեսված սպեկտրաբևեռաչափին և կարող է կիրառվել օպտիկական սարքաշինության մեջ: Շրջանային դիքրոիզմի սպեկտրի չափման սարքն ունի լույսի աղբյուր, հեղուկ բյուրեղային բևեռացնող դիֆրակցիոն ցանց, ընդունիչներ: Գյուտի համաձայն լույսի...

Շրջանային դիքրոիզմի սպեկտրի չափման սարք, որն ունի լույսի աղբյուր, հեղուկ բյուրեղային բևեռացնող դիֆրակցիոն ցանց, ընդունիչներ. տարբերվում է նրանով, որ լույսի աղբյուրը բարձր ճնշմամբ քսենոնի լամպ է, լույսի աղբյուրի և հետազոտվող նմուշի միջև տեղակայված է մոնոքրոմատոր, որպես ընդունիչներ օգտագործված են երկու ֆոտոընդունիչներ, դրանց միացված է լոգարիթմական իմ...

nvention relates to the field of optic instrument engineering, in particular, to development of a spectral polarimeter for registration of circular dichroism within a wide spectral range and may be used in optic instrument engineering. The device for measurement of circular dichroism spectrum consists of a light source, an LCD polarisation diffract...

A mathematical model of a new type of liquid crystal (LC) based diffraction grating for the terahertz frequency range is proposed. Numerical time-integration by the finitedifference time-domain (FDTD) method of Maxwell-equation systems, describing the proposed structure, has been performed. The partial differential equation, describing the electro-...

The light propagation in an anisotropic periodic media, such us circular diffraction waveplate (CDW) by a finite-difference time-domain (FDTD) technique is studied. The FDTD numerical simulation and the subsequent Fourier transform of the diffracted electric near field was been used for study of ability of CDW to diffract a laser beam and simultane...

The invention relates to optics, in particular, to studying a new method of optical measurements and may be used in polarimetry, in spectropolarimetry and ellipsometry. The method is proposed to register variation of a polarised vector of a monochromatic light wave, which is based on application of an axial-symmetrical liquid-crystal delayer and a...

Conformation changes of calf thymus DNA induced by nanomole concentrations of Co(+2) and TOEPyP4 and influence of this ion on porphyrin binding mode with DNA duplex were studied at two NaCl concentrations (10 and 100 mM) using circular dichroism spectroscopy and absorption data. It was shown that addition of 85 nM Co(+2) into TOEPyP4/DNAb.p. = .015...

It is known that at low concentrations of TMPyP4, this porphyrin predominantly intercalates between GC pairs at GC-rich sites of duplex DNA and G-quadruplexes of various constructions, and stabilizes these structures. However, there are still some arguable suggestions about the exact binding sites and modes of TMPyP4 to GC-rich regions of DNA in ca...

In this paper, a device and technique for circular dichroism (CD) recording in the fixed spectral range and in real time are developed. In CD spectroscopy the requirement for precision measurements of the light intensity is one thousandth of a percent. In order to expand the dynamic range the control of data accumulation time is provided. Two NMOS s...

A new type of the light polarization state analyzer, based on the simultaneous use of an axially symmetric liquid crystal transparency and cycloidal diffractive waveplate is proposed.

A new type of the light polarization state analyzer, based on the simultaneous use of an axially symmetric liquid crystal transparency and cycloidal diffractive waveplate is proposed.

As a polarization diffraction grating (PDG) the liquid crystal planar-planar periodic structures, the static diffraction efficiency of which is limited by the presence of twist tension, are observed. The behavior of the given structure in dynamic mode is interesting due to the possibility of the diffraction efficiency control, when under the action...

Recently, due to application of optical tweezers an optical trapping and manipulation of tiny particles using a highly focused laser beam became possible. It has become an integral part of study the mechanics of biomolecules and bio-molecular processes because aside from being able to move particles in the nanometer-scale. In designing of optical t...

Theory and simulations Vortex retarders are components with uniform retardance, fast axis of which rotates around its center. Circular diffraction waveplates are generally described as periodic profiles of spatially varying optical anisotropy. ASW is created by exposed light passing through the rotated polarizer and narrow slit, when the CDW is wri...

Theory and simulations Vortex retarders are components with uniform retardance, fast axis of which rotates around its center. Circular diffraction waveplates are generally described as periodic profiles of spatially varying optical anisotropy. ASW is created by exposed light passing through the rotated polarizer and narrow slit, when the CDW is wri...

The diffraction efficiency dynamics of planar-planar periodic liquid crystal structure under the influence of quasistatic (1 kHz), as well as pulse electric fields is studied. In quasistatic control mode ±1 diffraction orders are observed in the voltage absence, and at the electric field switching on the diffraction disappears, that is, only zero o...

The known devices for CD measuring are based on the light beam splitting to right- and left-circular polarized components by photo-elastic modulators, operating in real-time only for polarized chromatic waves. In this paper we propose to use non-polarized radiation for CD measurement. In the non-polarized light the wave can be presented as a compos...

Today, due to the rapid development of photonics special attention is paid to technology of light modulation and optical signal processing. In applications for processing and optical information storage the key elements are optical valves, phase plates and spatial light modulators based on liquid crystal (LC). The basic functional unit of these dev...

A new type of the light polarization state analyzer, based on the simultaneous use of an axially symmetric liquid crystal transparency and polarization diffraction grating (PDG) is proposed.

New type of liquid crystal diffraction grating for terahertz frequency is proposed. The process of molecules orientations in external electric field are calculated by the method of lines. FDTD numerical model is presented and the possibility of using proposed structure as a spatial switch in the terahertz range is shown.

In spectrophotometry, while registering small signals, it is important to realize the record of light with low signal/noise ratio in linear photodetection mode. For example, in the circular dichroism (CD) spectroscopy the requirement for precision measurements of the light intensity is one hundredth of a percent. In this paper a device and techniqu...

CD spectra of (DNA-TOEPyP4) + ZnTOEPyP4, (DNA-ZnTOEPyP4) + TOEPyP4, and DNA + (TOEPyP4-ZnTO- EPyP4) complexes have been studied. It is shown that CD spectra of these triple complexes significantly differ from the DNA-TOEPyP4 and DNA-ZnTOEPyP4 double complex spectra, and they are not sum of these double complexes. Especially some strong differences...

The invention refers to photonics, in particular to the development of optoelectronic components of photonics. Possible fields of the invention application are: adaptive optics, optical correlation, image processing, holographic record, as well as displays. In order to control the birefringence of planar oriented nematic liquid crystal simultaneous...

The dynamics of reorientation processes of planar oriented nematic liquid crystals can be controlled and improved by 1 kHz continuous, as well as pulsed, auxiliary electric fields. A device and a special software for forming a control signal of complex shape are created. We show that using a four-step control signal for optical switching allows fiv...

We investigated the dependence of angular dispersion of replica on its distance from the master polarization diffraction grating (PDG). The distribution of field diffracted on master PDG was calculated using the method of finite-difference time-domain. According to the numerical model, within the transition region, conditioned by interference of se...

We investigate theoretically and experimentally the process of turn-on time control of a nematic liquid crystal (NLC) based phase retarder by means of an additional control voltage. We propose a theoretical model of reorientation of NLC molecules in crossed electric fields (conventional transverse field and additional longitudinal field). The dynam...

New method of restoring the phase shift of the light passing through the nematic liquid crystal (NLC) has been developed. Hilbert transformation supported by Unwrap function of Matlab software is proposed to be used for recovering phase shift from experimentally obtained data of light intensity vs. applied voltage. The method makes the phase shift...

The influence of longitudinal voltage, applied along semiconductor substrate of planar-oriented liquid-crystal cell, on the birefringence of nematic liquid crystal (NLC) has been studied. It is shown that with the fixed value of transverse voltage the application of longitudinal voltage creates an additional possibility to control the electro-optic...

The results of theoretical studies and numerical simulation of the reorientation process of nematic liquid crystal (NLC) director with planar orientation in the external electric field with random nonzero boundary values of the director tilt angle are given. The numerical solution of Erickson–Leslie equation describing the dynamics of director tilt...

Influence of the longitudinal voltage applied along the semiconductor substrate of a planar-oriented liquid crystal cell on the birefringence of a nematic liquid crystal (NLC) was investigated. It is shown that for a fixed magnitude of the transverse field the application of a longitudinal voltage creates an additional possibility to control the el...

We present results of studies of main characteristics of electrically-controlled retarders fabricated on the basis of planar- and twist-oriented liquid crystals (LC). The investigated characteristics are time of switching and the calibration curve of controllable phase incursion. Computer simulation and numerical calculations of the processes of LC...

Приведены результаты исследований основных характеристик электрически-управляемых фазовых пластинок, изготовленных на основе планарно- и твист-ориентированных нематических жидких кристаллов (ЖК) – времени переключения и калибровочной кривой контролируемого фазового набега. Проведены компьютерное моделирование и численные расчеты процессов переориен...

Проведено исследование влияния продольного напряжения, приложенного вдоль полупроводниковой подложки планарно-ориентированной жидкокристаллической ячейки, на двулучепреломление нематического жидкого кристалла (НЖК). Показано, что при фиксированном значении поперечного поля приложение продольного напряжения создает дополнительную возможность управле...

In the present work the results of detailed researches on characteristics of transient processes, appearing by application of DC field to semiconductor substrate of liquid crystal cell have been carried out. It is shown, that oscillations, caused by longitudinal DC field applied to the semiconductor differ from the oscillations, caused by the Freed...

In modern technology media, where it is possible to record the optical information at high speed and density, using low light intensities, are necessary for information processing and storage. From that standpoint, materials with observable photorefracting phenomena are of special interest. Among these materials, it is necessary to single out liqui...

Inthepresentworktheresultsofdetailedresearchesoncharacteristicsoftransient processes,appearingbyapplicationofDCfieldtosemiconductorsubstrateof liquidcrystalcellhavebeencarriedout.Itisshown,thatoscillations,causedby longitudinalDCfieldappliedtothesemiconductordifferfromtheoscillations, causedbytheFreedericksztransitions.Thedependencesofcharacterandn...

In the present work the results of detailed researches on characteristics of transient processes, appearing by application of DC field to semiconductor substrate of liquid crystal cell have been carried out.It is shown, that oscillations, caused by longitudinal DC field applied to the semiconductor differ from the oscillations, caused by the Freed...

In modern technology media, where it is possible to record the optical information at high speed and density, using low light intensities, are necessary for information processing and storage. From that standpoint, materials with observable photorefracting phenomena are of special interest. Among these materials, it is necessary to single out li...