Third harmonic order imaging as a focal spot diagnostic for high intensity laser-solid interactions

Dromey, B. and Bellei, C. and Carroll, D.C. and Clarke, R.J. and Green, J.S. and Kar, S. and Kneip, S. and Markey, K. and McKenna, P. (2009) Third harmonic order imaging as a focal spot diagnostic for high intensity laser-solid interactions. Laser and Particle Beams, 27 (2). pp. 243-248. ISSN 0263-0346

Abstract

As the state of the art for high power laser systems increases from terawatt to petawatt level and beyond, a crucial parameter for routinely monitoring high intensity performance is laser spot size on a solid target during an intense interaction in the tight focus regime (< 10 mu m). Here we present a novel, simple technique for characterizing the spatial profile of such a laser focal spot by imaging the interaction region in third harmonic order (3 omega(laser)). Nearly linear intensity dependence of 3 omega(laser) generation for interactions > 10(19) Wcm(-2) is demonstrated experimentally and shown to provide the basis for an effective focus diagnostic. Importantly, this technique is also shown to allow in-situ diagnosis of focal spot quality achieved after reflection from a double plasma mirror setup for very intense high contrast interactions (> 10(20) Wcm(-2)) an important application for the field of high laser contrast interaction science.

Actions (login required)