multi-terawatt IR light

The Light Wave Synthesizer - 20 (LWS-20) is the world’s first multi-terawatt, few-cycle, sub-10-fs source. It is based on broadband optical parametric chirped pulse amplification (OPCPA) and its first version delivered 8-fs, 130-mJ, 800-nm pulses at 10 Hz repetion rate. It will be upgraded from 10 TW to 100 TW, currently delivering 16-TW (∼8 fs, 130 mJ) pulses. Front end: Ti:sapphire oscillator (Rainbow, Femtolasers) producing ∼5.5 fs CE-phase-stabilized pulses with a spectrum covering the spectral range of 670 – 970 nm, preamplified in a multipass Ti:Sa amplifier (Femtopower Compact Pro CE phase) and spectrally broadened in a neon-filled hollow-core fibre to yield a broadband sub-millijoule near-IR continuum for seeding the OPA chain. A specially-designed grism stretcher with negative group-delay dispersion broadens the pulses to ∼45 ps. OPCPA is performed in two consecutive BBO crystals, pumped by a commercial 80-ps, 1-J Nd:YAG laser (EKSPLA) and provides gain over the band of ∼700 – 1000 nm. A high transmission compressor consisting of different types of glass blocks and four chirped mirrors yields sub-8-fs multi-terawatt pulses. The output is optimized for Fourier-limited performance with an acousto-optical dispersive filter (DAZZLER).

The output pulses exhibit an intensity contrast of some 8 orders of magnitude in the ±40 ps temporal gain window of the OPA amplifier and of orders of magnitude better outside this window. By using the crossed-polarized wave generation technique this contrast is improved to some 10 orders of magnitude outside a 5-ps window preceding the pulse and it orders. Plasma mirror is implemented in the system and improves the contrast to 10 orders of magnitude up to 5-ps, 13 orders of magnitude up to 40-ps an 19 orders of magnitude before the main pulse. A Shack-Hartmann wavefront sensor and an adaptive mirror in a closed loop configuration are used to correct for wavefront distortions and thereby optimize focusing, which allows peak intensities in excess of 10^{19} W/cm² with our current 16-TW pulses.

A further upgrade to 5-fs and ∼100 TW is under progress. We pursue multi-color OPA synthesis of frequencies ranging from the visible to mid infrared using a combination of Nd:YAG fundamental, second-harmonic, and possibly third-harmonic pumping for providing several-octave high-field optical waveform synthesis and multi-terawatt single-cycle pulses for attosecond science. Furthermore, we will incorporate a single-short CE-phasemeter to measure, stabalise and control the CE-phase.
contact: L. Veisz

References:

Generation of sub-three-cycle, 16 TW light pulses by using noncollinear optical parametric chirped-pulse amplification, D. Herrmann, L. Veisz, R. Tautz,F. Tavella, K. Schmid, V. Pervak, F. Krausz Opt. Lett. 34, 2459 (2009)

Dispersion management for a sub-10-fs, 10 TW optical parametric chirped-pulse amplifier, F. Tavella, Y. Nomura, L. Veisz, V. Pervak, A. Marcinkevicius, Opt. Lett. 32, 2227 (2007)