Recording of polarization holograms in a liquid crystal cell with a photosensitive chalcogenide orientation layer [Invited]

Sheremet, N.; Kurioz, Yu.; Slyusarenko, Kostyantyn; Trunov, M. L.; Reznikov, Yuriy

doi:10.1364/ao.52.000e40

Cited by 20 publications

(11 citation statements)

References 33 publications

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“…Because the induced birefringence value for the Azo-Pam-II film is a bit higher, we use this material for recording of polarization diffraction gratings. The gratings are formed with the spatially modulated light-induced direction of anisotropy on the Azo-Pam-II film surface recorded by two beams with opposite circular polarizations. , The optical scheme for recording of the polarization diffraction gratings is shown in Figure S9 . We start the recording of polarization holographic gratings with the two circular oppositely polarized Gaussian beams from the Ar laser (wavelength λ = 532 nm, power P ≤ 100 mW).…”

Section: Resultsmentioning

confidence: 99%

Photoactive Fluorinated Poly(azomethine)s with Azo Groups in the Main Chain for Optical Storage Applications and Controlling Liquid Crystal Orientation

Kovalchuk

Kobzar

Ткаченко

et al. 2019

ACS Appl. Polym. Mater.

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Polymer multicomponent materials containing conjugated fragments (such as azo- or azomethine groups) have attracted significant attention due to their possible use in the efficient reversible stimuli-responsive, light-responsive devices. Light-responsive polyazomethines with azo groups in the backbone (Azo-Pams) are synthesized by polycondensation of tetrafluorobenzene- or octafluorobiphenylene-based bis-hydroxybenzaldehydes with hexamethylenediamine. The polymers feature the simultaneous combination of azo and azomethine groups inside one conjugated block. The synthesized polymers can be solution cast into flexible solid films with tensile strength of about 24 MPa. We found that the obtained Azo-Pam polymers have an amorphous structure (T g ∼ 134 °C) and high thermal stability (up to 300 °C). Their optical spectra depend on the solvent type and its pH which influence the dynamical equilibrium between the tautomeric forms. It also determines the balance between the main (azo form) and the ionized form in the solvent and allows to purposefully regulate the absorption maxima. We demonstrate the ability to record optical information using Azo-Pam films in the form of polarization gratings (holograms) with a regulated diffraction efficiency. A uniform orientation of liquid crystal is achieved by a polarized UV irradiation of glass substrates covered with the polymer Azo-Pam-II. The obtained data show that the synthesis strategy of the Azo-Pam polymers is an effective instrument for designing a wide range of stimuli-responsive and optical active materials.

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Section: Resultsmentioning

confidence: 99%

Photoactive Fluorinated Poly(azomethine)s with Azo Groups in the Main Chain for Optical Storage Applications and Controlling Liquid Crystal Orientation

Kovalchuk

Kobzar

Ткаченко

et al. 2019

ACS Appl. Polym. Mater.

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“…Sheremet et al studied this type of photoalignment on As 2 S 3 films for a LC 5CB and on As 20 Se 80 films for LCs 5CB and E7. [3,4] The distinctive feature of the present observations is sensitivity of the photoalignment to the direction of the light irradiation; despite the equal light intensities, the alignment was achieved at the direct irradiation of the outer chalcogenide surface, and it was not observed at the irradiation through the chalcogenide layer (Figure 3(a)). The only asymmetry during the irradiation is the difference in the light intensity distribution in the case of the light beam propagating through the chalcogenide layer because of the light absorption in the chalcogenide material ( Figure 5).…”

Section: Discussionmentioning

confidence: 60%

“…The photoalignment of LC on another type of chalcogenide glass (As 20 Se 80 ) in the LC cell was also found in [3] and used for the hologram recording. [4] Gelbaor et al [5] observed a light-induced alignment of a LC after irradiation of a chalcogenide film before the cell filling. The characteristics of photoalignment at the irradiation of the chalcogenide layer before and after the cell filling were different.…”

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confidence: 99%

Photoalignment in the isotropic phase of liquid crystal on chalcogenide glass film

et al. 2014

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We discovered the phenomenon of liquid crystal (LC) alignment on a photosensitive chalcogenide glass film As 20 Se 80 after irradiation of the LC in the isotropic phase with polarised light. The photoalignment was observed after cooling of the LC to the nematic phase. Quality of the photoalignment depended on an initial phase state of the LC. If the photoalignment was uniform at the irradiation of the isotropic phase of the LC that initially was pre-aligned in the nematic phase, the irradiation of the cell being filled in the isotropic phase resulted in inhomogeneous photoalignment. The orientation of the LC strongly depended on the geometry of the irradiation the LC in the cell. In the case of the direct irradiation of the chalcogenide surface, the photoorientation of the LC was stable. On the contrary, the irradiation of the chalcogenide surface through the LC layer led to the temporal photoalignment that diminished within few days. The results are explained in the frame of the model that suggests two mechanisms of photoalignment. The first one is related to a light-induced anisotropy on chalcogenide layer and the second one involves a LC in the process. We assume that an anisotropic light-induced desorption of LC molecules from the chalcogenide layer is the origin of last kind of photoalignment. The asymmetry of the photoalignment properties at the irradiation from the different sides of the chalcogenide surface is explained by producing different surface structures at the irradiation from the different sides.

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“…Therefore, many types of photoalignment materials, methods for periodic alignment, and diffraction properties of grating LC cells have been studied. [1][2][3][4][5][6][7][8][9][10][11][12] Crawford et al demonstrated the fabrication of switchable LC gratings by polarization holographic exposure on linearly photopolymerizable polymer alignment layers. 6) In the polarization holographic exposure, the intensity of the interference field is constant; however, polarization states are periodically modulated.…”

Section: Introductionmentioning

confidence: 99%

Blazed vector grating liquid crystal cells with photocrosslinkable polymeric alignment films fabricated by one-step polarizer rotation method

Kawai

Kuzuwata

Sasaki

et al. 2014

Jpn. J. Appl. Phys.

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Blazed vector grating liquid crystal (LC) cells, in which the directors of low-molar-mass LCs are antisymmetrically distributed, were fabricated by one-step exposure of an empty glass cell inner-coated with a photocrosslinkable polymer LC (PCLC) to UV light. By adopting a LC cell structure, twisted nematic (TN) and homogeneous (HOMO) alignments were obtained in the blazed vector grating LC cells. Moreover, the diffraction efficiency of the blazed vector grating LC cells was greatly improved by increasing the thickness of the device in comparison with that of a blazed vector grating with a thin film structure obtained in our previous study. In addition, the diffraction efficiency and polarization states of +1st-order diffracted beams from the resultant blazed vector grating LC cells were controlled by designing a blazed pattern in the alignment films, and these diffraction properties were well explained on the basis of Jones calculus and the elastic continuum theory of nematic LCs.

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Recording of polarization holograms in a liquid crystal cell with a photosensitive chalcogenide orientation layer [Invited]

Cited by 20 publications

References 33 publications

Photoactive Fluorinated Poly(azomethine)s with Azo Groups in the Main Chain for Optical Storage Applications and Controlling Liquid Crystal Orientation

Photoactive Fluorinated Poly(azomethine)s with Azo Groups in the Main Chain for Optical Storage Applications and Controlling Liquid Crystal Orientation

Photoalignment in the isotropic phase of liquid crystal on chalcogenide glass film

Blazed vector grating liquid crystal cells with photocrosslinkable polymeric alignment films fabricated by one-step polarizer rotation method

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