Light propagation in periodic photonic structures formed by photo-orientation and photo-polymerization of nematic liquid crystals

Rutkowska, Katarzyna A.; Chychłowski, Miłosz; Kwaśny, Michał; Ostromęcka, Iga; Pilka, Jacek; Laudyn, Urszula A.

doi:10.1016/j.opelre.2017.05.004

Cited by 9 publications

(5 citation statements)

References 32 publications

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“…In case of PSLCs, the polymer network is formed in between LC molecules and stabilizes the molecular arrangement, as the concentration of monomer is quite low (<10%) [1,2]. Such a network allows to not only expand the temperature stability of the LC phase [3][4][5][6], but to also preserve the desired orientation of LC molecules that was initially obtained under the influence of an external factor such as an electric field [7][8][9][10][11][12]. When it comes to PDLCs, the polymer concentrations typically range from ~20% to 80% [1].…”

Section: Introductionmentioning

confidence: 99%

Dual-Period Polarization-Dependent Diffraction Gratings Based on a Polymer-Stabilized Liquid Crystal

Kajkowska,

Chychłowski,

Ertman

et al. 2023

Materials

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In this paper, we demonstrate the first ever dual-period diffraction gratings that do not require electrical tuning to obtain the effect of period change. Our method allows for multiplication of the base period by proper modification of the subsequent slits of the grating. The proposed elements are fabricated by selective photopolymerization of a composite based on a nematic liquid crystal. The gratings are formed by polymer stabilization of a liquid crystal in different orientations of the molecules in selected grating slits to allow for period manipulation. The operating principle is based on changing the phase delay introduced by the slits depending on polarization direction of incident light with respect to the director in each type of slit, which allows to change the grating’s period. The proposed technique was successfully utilized to obtain diffraction gratings with either doubling or tripling of the period.

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Section: Introductionmentioning

confidence: 99%

Dual-Period Polarization-Dependent Diffraction Gratings Based on a Polymer-Stabilized Liquid Crystal

Kajkowska,

Chychłowski,

Ertman

et al. 2023

Materials

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“…Due to the strong sensitivity of LCs to various external stimuli, it is possible to generate periodic structures built from LCs with periodically modulated stimuli, for instance, by using periodic electrode configurations [ 28 , 40 ] or via periodic alignment layers. The latter can be achieved either by rubbing [ 41 , 42 ] or by photo-alignment [ 43 , 44 ]. The advantage of photo-alignment over rubbing-based alignment is that its fabrication process is noncontact, which is suitable for inaccessible areas, e.g., in organic electronics [ 45 ].…”

Section: Introductionmentioning

confidence: 99%

Electrically Tuneable Optical Diffraction Gratings Based on a Polymer Scaffold Filled with a Nematic Liquid Crystal

et al. 2021

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We present an experimental and theoretical investigation of the optical diffractive properties of electrically tuneable optical transmission gratings assembled as stacks of periodic slices from a conventional nematic liquid crystal (E7) and a standard photoresist polymer (SU-8). The external electric field causes a twist-type reorientation of the LC molecules toward a perpendicular direction with respect to initial orientation. The associated field-induced modification of the director field is determined numerically and analytically by minimization of the Landau–de Gennes free energy. The optical diffraction properties of the associated periodically modulated structure are calculated numerically on the basis of rigorous coupled-wave analysis (RCWA). A comparison of experimental and theoretical results suggests that polymer slices provoke planar surface anchoring of the LC molecules with the inhomogeneous surface anchoring energy varying in the range 5–20 μJ/m2. The investigated structures provide a versatile approach to fabricating LC-polymer-based electrically tuneable diffractive optical elements (DOEs).

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“…The deformed director field can be stored in the NLC bulk by a photoinduced polymer network in the nematic matrix. In such a way, the periodic (photonic) structure [16] and the structure with large in-plane refractive-index gradient [17] were recorded.…”

Section: Introductionmentioning

confidence: 99%

Phase Structure Recording in a Nematic Side-Chain Liquid-Crystalline Polymer

et al. 2020

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Dye-doped nematic side-chain liquid-crystalline polymers possess extraordinary large optical nonlinearity and ability to store the induced orientational deformations in a glassy state, which makes them a very promising material for photonic applications. In this study, the phase structures were generated and recorded in the bulk of a 50-μm layer of a nematic liquid-crystalline side-chain polymer, containing polyacrylate backbone, spacer having five methylene groups, and phenyl benzoate mesogenic fragment. The polymer was doped with KD-1 azodye. The director field deformations induced by the light beam close to the TEM01 mode were studied for different geometries of light–polymer interaction. The phase modulation depth of 2π was obtained for the 18-μm spacing between intensity peaks. The experimental data were analyzed based on the elastic continuum theory of nematics. The possibility to induce and record positive and negative microlenses in the polymer bulk was shown experimentally.

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Light propagation in periodic photonic structures formed by photo-orientation and photo-polymerization of nematic liquid crystals

Cited by 9 publications

References 32 publications

Dual-Period Polarization-Dependent Diffraction Gratings Based on a Polymer-Stabilized Liquid Crystal

Dual-Period Polarization-Dependent Diffraction Gratings Based on a Polymer-Stabilized Liquid Crystal

Electrically Tuneable Optical Diffraction Gratings Based on a Polymer Scaffold Filled with a Nematic Liquid Crystal

Phase Structure Recording in a Nematic Side-Chain Liquid-Crystalline Polymer

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