Creation of a Lens by Field Controlled Variation of the Index Of Refraction in a Liquid Crystal

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Electrical Engineering and Computer Science


Stephen T. Kowel


Cascaded liquid crystal cells

Subject Categories

Electrical and Computer Engineering


A lens created by field controlled variation of the index of refraction in a liquid crystal cell has been analyzed and empirically verified. To obtain a spherical lens capable of focusing arbitrary incoming polarizations while maintaining a simple electrode structure requires four cascaded liquid crystal cells. With electrodes fabricated well within the microelectronics state-of-the-art, near diffraction limited performance in terms of the Optical Transfer Function is predicted.

The focusing capability of a liquid crystal lens was demonstrated using a single cell with linear transparent electrodes. A plano-convex cylindrical lens for a single incoming polarization was created. Fringing along the edge of the electrodes was observed. This is a requirement for the near diffraction limited performance theoretically predicted.

A liquid crystal lens holds great promise. Since the ultimate phase front is electronically controlled, capability exists to compensate for system aberrations and accomplish adaptive optic techniques. Also, since the focal length is electronically controlled, the lens or a lens assembly containing the liquid crystal lens as an element can be focused without mechanical motion. These capabilities are achievable while maintaining the inherent liquid crystal benefits of low drive voltage, low power consumption, and light weight.


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