Liquid Crystals as High Repetition Rate Targets for Ultra Intense Laser Systems

Abstract

This thesis presents the development of and first experiments on freely suspended liquid crystal film targets for intense laser-matter experimentation. Liquid crystals exhibit additional phases between solid and liquid which are characterized by different levels of molecular ordering. One of these, the smectic phase, entails molecular orientational order and positional order such that the constituent molecules arrange into layers of set thickness. The surface tension inherent to this smectic phase allows a liquid crystal film to be formed within an aperture in a rigid frame; control over the parameters of film formation (temperature, volume, wiper speed, etc.) allows the number of layers comprising this freely suspended film to be modified on-demand. The result is a variable thickness target with planar geometry that is robust to target chamber vacuum environments and is also inexpensive due to the low volume used per film.