A5000471434- Liquid Crystal Research Advancements
- Phase-change materials and chalcogenides
- Optical Polarization and Ellipsometry
- Plant Reproductive Biology
- GaN-based semiconductor devices and materials
- ZnO doping and properties
- Ga2O3 and related materials
- Nonlinear Optical Materials Studies
- Orbital Angular Momentum in Optics
- Semiconductor materials and devices
- Micro and Nano Robotics
- Experimental and Theoretical Physics Studies
- Photocathodes and Microchannel Plates
Institute of Physics
2012-2021
Bilkent University
2017-2018
National Academy of Sciences of Ukraine
2012-2017
Polarization gratings have been recorded in a combined liquid crystal (LC) cell made of substrate covered with photosensitive chalcogenide orientation layer and reference rubbed polyimide film. The are formed due to the spatially modulated light-induced easy axis on surface by two beams opposite circular polarizations. permanent, but they can be erased one recording re-recorded. diffraction intensity circularly polarized light is achromatic does not depend birefringence LC. efficiency...
Abstract The present paper reports on our recent achievements including the photoalignment achieved of liquid crystals (LCs) using amorphous chalcogenide semiconductors (AChS) glassy films and creation optically addressed spatial light modulators (OASLMs). in this case is based phenomenon photoinduced anisotropy, essentially found to be efficient nano‐dimentional (ND, <50 nm) AChS while OASLM action their photosensitivity.
We present basic characteristics and a model of photoinduced anchoring liquid crystals (LCs) on chalcogenide surface. It was found that the alignment strongly depend LC material for same glass. The photoalignment is partially reversible can be controlled by changing light polarization direction. propose in which existence dichroic units surface competition between two mechanisms suggested. first mechanism related to light-induced anisotropy results an easy orientation axes parallel incident...
We discovered the phenomenon of liquid crystal (LC) alignment on a photosensitive chalcogenide glass film As20Se80 after irradiation LC in isotropic phase with polarised light. The photoalignment was observed cooling to nematic phase. Quality depended an initial state LC. If uniform at that initially pre-aligned phase, cell being filled resulted inhomogeneous photoalignment. orientation strongly geometry cell. In case direct surface, photoorientation stable. On contrary, surface through...
Recent studies of photoalignment liquid crystals (LCs) on chalcogenide surfaces have a rich variety mechanisms responsible for the these materials. Both surface-mediated and LC bulk-mediated were observed. We report investigation toward understanding origin photoalignment. The contributions light-induced optical surface morphological anisotropy studied. Light-induced in film was observed by polarization interferometry measured high-resolution x-ray reflectivity. data reveals lack strong...
First observations of permanent light-induced director patterning in a transparent liquid crystal (LC) are reported. The was observed an LC cell with one the substrates covered chalcogenide film. Concentric ring pattern appears following irradiation surface through layer by Gaussian beam. experimental results explained terms heat transfer from film to after light absorption Heating changes its birefringence according spatial intensity distribution This turn leads spatially oscillating...
The results of high-resolution x-ray reflectivity study nano-dimensionally thin arsenic trisulfide (As2S3) glass films reveal surface roughness anisotropy upon prolonged irradiation with polarized 436 nm blue light. correlates the photoinduced and LC photoalignment observed on these films. However, As2S3 film's thickness reduces drastically during experiments, ambient oxygen moisture penetrate film create a second altered layer top thicker As2S3. confirm viability for non-contact material...
Abstract In the present work, we report light-induced rotation of millimeter-sized objects driven by their non-symmetric shape. The torque is originated thermal gradient on different sides teeth star-shaped floating liquid surfaces that leads to unbalanced surface tension due Marangoni effect. dependence angular number demonstrated. velocity linearly dependent light intensity and follows a simple time behavior typical moving under fluid friction. Graphic abstract
We report the first observation of light-induced director patterns formation in a planar liquid crystal (LC) cell with photosensitive chalcogenide film As20Se80. The angular appear under irradiation surface by Gaussian laser beam through LC layer was observed. experimental results are explained terms transfer heat from to after light absorption layer. Light-induced heating causes change birefringence and, as result, spatially modulated polarization state plane Since is photoaligning...