Moderate repetition rate ultra-intense laser targets and optics using variable thickness liquid crystal films

Abstract

Liquid crystal films are variable thickness, planar targets for ultra-intense laser matter experiments such as ion acceleration. Their target qualities also make them ideal for high-power laser optics such as plasma mirrors and waveplates. By controlling parameters of film formation, thickness can be varied on-demand from 10 nm to above 50 μm, enabling real-time optimization of laser interactions. Presented here are results using a device that draws films from a bulk liquid crystal source volume with any thickness in the aforementioned range. Films form within 2 μm of the same location each time, well within the Rayleigh range of even tight F/# systems, thus removing the necessity for realignment between shots. The repetition rate of the device exceeds 0.1 Hz for sub-100 nm films, facilitating higher repetition rate operation of modern laser facilities.

Laser-driven ion acceleration via target normal sheath acceleration in the relativistic transparency regime

“…This is enabled first by high contrast (via a plasma mirror) interaction, as superior laser pulse quality is required for successful ion acceleration from ultra-thin targets, and secondly by an in situ target formation system using freely suspended liquid crystal films [27]. This material can be drawn across an aperture in a rigid frame with changes in wiping speed, temperature, and liquid crystal volume to form films several mm in diameter at repetition rates of 0.1 Hz and with thicknesses from 10 nm to several 10 s of μm [28]. Critically, the in situ target formation device forms films to within 2 μm of the same position each formation, removing the necessity for between-shot target alignment and thus allowing rapid data collection.…”

Targets for high repetition rate laser facilities: needs, challenges and perspectives

“…However, ultrathin membranes are fragile and can be damaged in transport from target laboratory to laser facility or due to irradiation of neighbouring targets. The use of liquid crystal films suspended in a metal frame has been recently proposed as an alternative solution [70] (see Paragraph 2.3.3).…”

“…Liquid crystal targets are produced directly in the interaction chamber by drawing a given volume of liquid crystal (hundreds of nanolitres) with a sharp blade sliding across an aperture on a metal frame [70] . Figure 19 shows the Linear Slide Target Inserted (LSTI) developed at the Ohio State University for the production of liquid crystal targets.…”

Generation of Attosecond Light Pulses from Gas and Solid State Media

“…In this way the targets are capable to acquire thousands of laser shots. Promising configurations which can potentially lead to a reliable XUV emission for a large number of laser shots are the tape-like solid targets [38], liquids [35] and liquid crystal films [36,37].…”

“…Due to the experimental obstacles mentioned before, the solid surface harmonics as a robust asec source (that can be utilized for further experiments) is still in the development phase and applicability up to now is mainly dedicated to the studies of the ultrafast dynamics of laser-plasma interaction [82][83][84][85][86]. Nevertheless, recent experiments performed in the non-linear XUV regime [54,92] and recent progress in the laser pulse engineering and solid target technology [5,6,[35][36][37]67] verifies the feasibility of using solid surface harmonics in ultrafast XUV spectroscopy and attosecond science.…”