14 May 2018

Status of high power laser system at ELI-NP

The first preliminary tests of NP’s laser system show promising results: an amplification of more than 120 Joules output before the last amplification crystal, more than necessary to achieve the targeted 3 petaWatt with a 25 femtosecond pulse duration.

The High Power Laser System (HPLS), under integration at ELI-NP [1, 2], is produced by a consortium formed by Thales Optronique SAS and Thales Systems Romania. This laser system is a Ti:Sapphire, hybrid CPA [3] system, and it consists of six optical outputs: two 0.1 petaWatt outputs running at 10 Hertz repetition rate, two 1 petaWatt outputs running at 1 Hertz and two 10 petaWatt outputs running at 1 shot per minute.

High performances demonstrated
During the first stage of implementation, Thales consortium demonstrated high performances for the 100 teraWatt and 1 petaWatt outputs of arm 1 of the ELI-NP HPLS in the Thales Optronique SAS laboratories in Elancourt, France [4].

Currently, the HPLS is under implementation in the ELI-NP facility in Măgurele, Romania at the Horia Hulubei – National Institute for Nuclear Engineering. At this moment all the equipment necessary for the implementation of the system is integrated in the laser room. This includes all the mechanical parts, like heavy compressor chambers, and all optical parts, such as the meter size optical gratings and the two 200 millimeter diameter Ti:Sa crystals necessary to reach the 2 x 10 petaWatt output powers.

Phase two
At this moment the intermediate stage of phase two of the contract is delivered and tests are ongoing. Parameters to be reached at the end of this stage are already at the state of the art: one arm of the laser has to be fully functional with the outputs running as following: one output at 100 teraWatt at 10 Hertz repetition rate, one output at 1 petaWatt at 1 Hertz repetition rate and one output at 3 petaWatt at 1 pulse per minute repetition rate. The additional beam parameters are also state of the art: pulse energy stability ≤ 5 percent RMS, Strehl ration ≥0.9 and intensity contrast of approxiametely 1:10¹².

Preliminary tests were performed with promising results that shown an amplification of more than 120 Joule output before the last amplification crystal, more than necessary to achieve the targeted 3 petaWatt considering a 25 femtosecond pulse duration.

The Laser Beam Transport System (LBTS) that ensures the delivery of the 2 x 10 petaWatt beam to the interaction chambers in the dedicated experimental areas (E1, E6 and E7) was tendered and a contract was awarded to the LBTS consortium in December 2017.

1. N.V. Zamfir, Rom. Rep. Phys., 2016 68 (Supplement), S3–S4
2. Extreme Light Infrastructure – Nuclear Physics (ELI-NP) White Book - http://www.eli-np.ro/documents/ELI-NP-WhiteBook.pdf- as in May 2016
3. Donna Strickland, Gerrard Mourou, Opti. Comm., 1985, 56(3), 219-221
4. Francois Lureau et. al. Proc. SPIE 9726, Solid State Lasers XXV: Technology and Devices, 972613 (2016)