Characterization of a nonlinear filter for the front-end of a high contrast double-CPA Ti:sapphire laser

Abstract

A nonlinear filter using rotation of the polarization ellipse in air is investigated. Scheme to enhance the temporal contrast is developed for a double-CPA multi-terawatt Ti:sapphire laser. It supports an energy level of millijoule and has a high efficiency. The method allows suppression of the ASE pedestal, pre- and post-pulses by 3 orders of magnitude and also steepens the pulse front. For the physical interpretation of the results, numerical simulation of the filtering is performed.

On the temporal contrast of high intensity femtosecond laser pulses

“…Due to the high temporal contrast, we were able to accelerate protons to energies ~5 MeV using thin (6 /Lm) Al target foils (Lindau et al, 2005). Further improvement of contrast may require more sophisticated techniques as use of a plasma mirror (Doumy et al, 2004) implementing a double-CPA system (Kalashnikov et al, 2004(Kalashnikov et al, , 2005 or frequency conversion (Uteza et al, 2005). …”

Temporal contrast of high intensity laser systems above 1011 with double CPA technique

“…Together with a permanently growing level of laser intensity available for interaction experiments, during the last few years considerable efforts have been devoted to increase the temporal ASE contrast of high intensity systems. These latters include the invention of the double chirped pulse amplification (DCPA) [2] architecture, that implements intermediate pulse recompression and nonlinear temporal filtering of the short pulse; investigation of nonlinear methods [3][4][5][6][7] required for the practical realization of a reliable DCPA, and also the development of plasma mirror technique [8], that supports substantial improvement of temporal contrast (up to four orders of magnitude), but is applicable only to low repetition rate systems. Despite that currently Ti:Sapphire lasers of up to a Petawatt power level with the ASE contrast ~ 10 9 are commercially available, development of a reliable front end that can allow temporal contrast of amplified and recompressed pulses of 10 10 and beyond is still challenging.…”

Contrast Improvement of Relativistic Few-Cycle Light Pulses

“…-elliptical polarization rotation in air Homoelle et al (2002); Jullien et al (2004); Kalashnikov et al (2004) is based on the nonlinear induced birefringence. The efficiency is 25-50 % depending on the configuration -single vs. multi pass-and on the chirp of the input pulse and the contrast enhancement is 3-4 OOM.…”