Liquid crystal films as on-demand, variable thickness (50-5000 nm) targets for intense lasers

TL;DR

This paper introduces a versatile liquid crystal film target for intense laser experiments, offering rapid, on-demand production with tunable thicknesses, low cost, and stable vacuum properties, demonstrated through initial ion acceleration results.

Contribution

It presents a novel liquid crystal film target design that can be quickly formed with adjustable thicknesses for laser experiments, improving flexibility and cost-effectiveness.

Findings

Films maintain their thickness in high vacuum conditions.

Ion acceleration data obtained from initial laser shots.

Target production cost is less than one cent per film.

Abstract

We have developed a new type of target for intense laser-matter experiments that offers significant advantages over those currently in use. The targets consist of a liquid crystal film freely suspended within a metal frame. They can be formed rapidly on-demand with thicknesses ranging from nanometers to micrometers, where the particular value is determined by the liquid crystal temperature and initial volume as well as by the frame geometry. The liquid crystal used for this work, 8CB (4'-octyl-4-cyanobiphenyl), has a vapor pressure below $10^{-6}$ Torr, so films made at atmospheric pressure maintain their initial thickness after pumping to high vacuum. Additionally, the volume per film is such that each target costs significantly less than one cent to produce. The mechanism of film formation and relevant physics of liquid crystals are described, as well as ion acceleration data from the first shots on liquid crystal film targets at the Ohio State University Scarlet laser facility.