Design and simulation of single-electrode liquid crystal phased arrays

Abstract

Liquid crystal (LC) phased arrays and gratings have been employed in optical switching and routing [1]. These diffractive optic elements are of great interest because they can be scaled up to a large number of elements and their optical properties can be electrically addressed with a low driving voltage. LC phase gratings have been achieved either by periodic addressing of pixels or by using periodically-modified structures. The latter approach leads to less reconfigurable devices but the addressing is simpler.In this paper we focus on optical phased arrays where the phase is varied either continuously or discretely and where the periodicity is induced by electrode configuration. We first describe a possible structure based on a conductive silicon wafer. We argue that this structure can induce either continuously or discretely varying arrays while applying single voltage to the array. In the second part we simulate the behaviour of such arrays. We base the simulation on a LC synthesized at the Military University of Technology, this high-birefringence nematic LC shows in a 4-μm thick cell a linear phase shift range of more than 360° between 1.2 V and 1.8 V. We calculate the distribution of the LC molecule director and assess the performance of the array with respect to the applied voltage. Finally, the relevance of such technology for switchable phased arrays is discussed.

Tunable one-dimensional photonic crystal slabs

“…However, it eases simple optical inspection of assembled devices. In the following we consider a LC with a birefringence ∆n = 0.38, characterized by ordinary and extraordinary indices of n o = 1.55 and n e = 1.93, respectively 28 . Such a high positive birefringence, low viscosity nematic liquid crystals is assumed to completely fill the finely structured grooves.…”

Total Internal Reflection in a Hybrid Nematic Cell Submitted to Weak Boundary Conditions

“…In addition, they can be integrated into other optical components and compact systems [5]. Different types of optical elements based on liquid crystals technology have been implemented [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In particular, liquid crystal technology has been applied to construct diffraction gratings that can electrically modulate the diffraction efficiency [21].…”

Tunable one-dimensional photonic crystal slabs based on preferential etching of silicon-on-insulator

“…In order to achieve a wide tuning range, we consider high positive birefringence (∆n = 0.38), low viscosity nematic liquid crystals [23], characterized by ordinary and extraordinary indices of n o = 1.55 and n e = 1.93, respectively. The static dielectric anisotropy (∆ε stat r ) of the liquid crystalline material equals 4.3, while the elastic constants can be fairly approximated by a value of K = 10 pN.…”