Citation
Velarde Mayol, Pedro and Oliva, Eduardo and Fajardo, Marta and Li, L. and Pittman, L. and Le, T. and Gautier, J. and Lambert, Guillaume and Ros, David and Sebban, Stéphane
(2012).
A proposal for multi-tens of GW fully coherent femtosecond soft X-ray lasers.
"Nature Photonics", v. 6
(n. 11);
pp. 764-767.
ISSN 1749-4885.
https://doi.org/10.1038/nphoton.2012.246.
Abstract
X-ray free-electron lasers1,2 delivering up to 131013 coherent photons in femtosecond pulses are bringing about a revolution in X-ray science3?5. However, some plasma-based soft X-ray lasers6 are attractive because they spontaneously emit an even higher number of photons (131015), but these are emitted in incoherent and long (hundreds of picoseconds) pulses7 as a consequence of the amplification of stochastic incoherent self-emission. Previous experimental attempts to seed such amplifiers with coherent femtosecond soft X-rays resulted in as yet unexplained weak amplification of the seed and strong amplification of incoherent spontaneous emission8. Using a time-dependent Maxwell?Bloch model describing the amplification of both coherent and incoherent soft X-rays in plasma, we explain the observed inefficiency and propose a new amplification scheme based on the seeding of stretched high harmonics using a transposition of chirped pulse amplification to soft X-rays. This scheme is able to deliver 531014 fully coherent soft X-ray photons in 200 fs pulses and with a peak power of 20 GW.
