The Chinese University of Hong Kong

The Hong Kong University of Science and Technology

Emma MacPherson

Edward Philip John Parrott

Vladimir Grigorievich Chigrinov

Fan Fan

Hongkyu Park

Xudong Liu

Benjamin Ung

Zefeng Chen

Jianbin Xu

A light modulator (e.g., for terahertz radiation) may be constructed using a prism in which light undergoes total internal reflection (TIR) at one surface. A tunable conductive layer is disposed on the TIR surface. The tunable conductive layer can have a conductivity that is dynamically controllable, e.g., by applying a voltage across the tunable conductive layer or by optically pumping the tunable conductive layer. The tunable conductive layer can absorb a portion of the reflected light beam, attenuating the beam, with the attenuation being a function of the electrical conductivity of the tunable conductive layer. The phase of the reflected light beam can also be altered as a function of electrical conductivity of the tunable conductive layer.

Light modulator using total internal reflection at an interface with a tunable conductive layer

A liquid crystal cell structure comprising transparent terahertz (THz) windows, alignment layers, protective layers, in-plane electrodes, out-of-plane electrodes, and a liquid crystal (LC) layer. The in-plane electrodes generate in-plane electric fields that are parallel to the liquid crystal layer and the out-of-plane electrodes generate out-of-plane electric fields that are perpendicular to the liquid crystal layer. The in-plane and out-of-plane electrodes have wire-grid patterns to increase THz wave transmission efficiency. The wire-grid patterned electrodes are transparent to THz waves that have parallel polarization compared to a grating vector of the wire grid pattern and are opaque to THz waves of perpendicular polarization. These two electrodes are controlled independently to tune the optical properties of the LC and improve the operating speed of THz LC devices.

Terahertz in-plane and terahertz out-of-plane switching liquid crystal devices

Growing community of inventors

Hong Kong, China

Emma MacPherson