Electrically Rotatable Polarizer Using One-Dimensional Photonic Crystal with a Nematic Liquid Crystal Defect Layer

Abstract

Polarization characteristics of defect mode peaks in a one-dimensional (1D) photonic crystal (PC) with a nematic liquid crystal (NLC) defect layer have been investigated. Two different polarized defect modes are observed in a stop band. One group of defect modes is polarized along the long molecular axis of the NLC, whereas another group is polarized along its short axis. Polarizations of the defect modes can be tuned by field-induced in-plane reorientation of the NLC in the defect layer. The polarization properties of the 1D PC with the NLC defect layer is also investigated by the finite difference time domain (FDTD) simulation.

On‐Demand Polarization Controllable Liquid Crystal Laser

“…However, in accordance with the findings reported for other polarization devices, the control of the polarization was limited as the orientation of the polarization state could not be controlled directly. In another configuration that has been reported, [44] the orientation of the polarization state of a A polarization controllable band-edge liquid crystal (LC) laser configuration is presented that provides on-demand control of the polarization state of the laser using a four electrode in-plane configuration to drive a nematic LC layer. By controlling the orientation of the electric field, and thus the orientation of the optic axis of the nematic LC, as well as the retardance, any laser polarization state (e.g., circular, elliptical) can, in principle, be created that is aligned along any desired direction in a plane perpendicular to the propagation direction.…”

“…However, in accordance with the findings reported for other polarization devices, the control of the polarization was limited as the orientation of the polarization state could not be controlled directly. In another configuration that has been reported, [ 44 ] the orientation of the polarization state of a defect‐mode laser created with two identical 1D photonic crystals comprising alternating SiO 2 –TiO 2 layers was controlled with a nematic LC layer by applying an in‐plane field. However, the number of alternating layers of SiO 2 –TiO 2 was crucial in creating a well‐defined polarization state.…”

Electric field-controlled transformation of the eigenmodes in a twisted-nematic Fabry–Pérot cavity

“…In such structures, the ease of controlling LCs by low voltages is combined with the high spectral resolution of the cavity 5–9 . This allows governing the intensity, phase, and polarization of the transmitted or reflected light 10,11 . It was analytically established that twisting of the optical axis of a nematic LC and the difference between the propagation constants of the extraordinary ( е ) and ordinary ( о ) waves in such a medium cause their coupling and form a new class of eigenmodes called twist extraordinary ( tе ) and twist ordinary ( tо ) waves 12 .…”