Recent Advances in Photoalignment Liquid Crystal Polarization Gratings and Their Applications

Abstract

Liquid crystal (LC) circular polarization gratings (PGs), also known as Pancharatnam–Berry (PB) phase deflectors, are diffractive waveplates with linearly changed optical anisotropy axes. Due to the high diffraction efficiency, polarization selectivity character, and simple fabrication process, photoalignment LC PGs have been widely studied and developed especially in polarization management and beam split. In this review paper, we analyze the physical principles, show the exposure methods and fabrication process, and present relevant promising applications in photonics and imaging optics.

Generation of the Planar Solitons Using Thermal Trapping of a Disclination in Nematic Liquid Crystals and Their Applications

“…Using the soliton, a polarization diffraction grating can be generated. This is because the structure of the soliton is in the form of a π-wall, which corresponds to one period of the general liquid crystal polarization diffraction grating [33][34][35][36][37] and therefore shows a diffraction depending on the polarization. By trapping and moving the topological charge freely using the thermal laser tweezer to create a soliton, the polarization diffraction grating with a high degree of freedom is easily generated.…”

Binary geometric-phase holograms

“…The continuous phase profile is a powerful GPH formulation due to its near-perfect diffraction efficiency into a single order subject to the input polarization. One of the simplest continuous GPHs is the polarization grating (PG) which is synonymous to a planar dynamic-phase prism [73,74,75,76]. A continuous PG, as shown Figure 2.8, possesses a spatially-varying optical axis Φ(x ) = πx /Λ, where Λ is the constant grating period, with phase cycles of 2π [22,75].…”

Filtration Properties of Polarization Holographic Gratings Recorded in Liquid Crystal Composites

“…В последнее время заметное внимание уделяется исследованию и перспективам практического использования поляризационных голографических решеток, сформированных в ЖК-композитах [2][3][4][5][6][7][8]. Такие решетки благодаря уникальным оптическим свойствам перспективны для создания модуляторов излучения, затворов, фильтров, оптических переключателей, разветвителей поляризованного излучения для устройств фотоники [9][10][11]. Они привлекательны тем, что сравнительно недороги, компактны, позволяют использовать относительно простую, одноэтапную технологию оптической записи, долговременно хранить поляризационное состояние, что обеспечивает высокую поляризационную селективность записанных поляризационных решеток.…”