Reaching the Millijoule-Regime via Ultrafast Optical Parametric Amplification – An Alternative to First Stage Regenerative Amplification Stages?

Abstract

A new ultra-high contrast uOPA module is being developed for the PHELIX- and PENELOPE frontend-chains. This module will enhance the ASE-contrast and prevent the formation of pre-pulses through a bypass of high-gain amplifiers.

High-Energy Laser Facility PHELIX at GSI: Latest Advances and Extended Capabilities

“…These measurements are performed after the fsFE and therefore not at full energy. However, owing to the low B-integral of the final passes in the main amplifier, we expect no significant changes to the shape of the curve at full energy [30] . Here, the ASElevel on the ns time scale is below 10 −12 with respect to the main pulse.…”

“…The improvement and control of the temporal contrast has been made possible by the implementation of a short-pulsepumped uOPA stage in the frontend [8,26] , which, by using the instantaneous nonlinear optical effect of parametric amplification, intrinsically provides an excellent temporal contrast outside the window of the ps-timescale pump pulse. The experience gathered with this system motivated the development of a more energetic version in a twostage configuration, delivering pulses up to the mJ energy range, which is now in operation [27][28][29] . This allowed to omit the linear regenerative amplifier stage that was previously in operation at the fsFE and was the origin of a number of prominent prepulses in the temporal shape.…”

“…Typical temporal pulse shape of the compressed PHELIX sub-ps pulse, measured with a high-dynamic-range third-order cross correlator. On top of a very low ASE background limited by the noise of the measurement device, the peaks before the main pulse are mainly due to artifacts [30,31] .…”