d. zimmer et al- table-top high repetition rate soft x-ray laser pumped in double-pulse single beam...

Table-top high repetition rate soft x-ray laser pumped in double-pulse single beam grazing incidence (DGRIP) D. Zimmer ∗1,2,3 , B. Zielbauer 1,2 , M. Pittman 1 , O. Guilb aud 1 , J. Habib 1 , S. Kazamias 1 , D. Ros 1 , V . Bagnoud 2 , B. Ecker 2,3 , D. Hochhaus 2,3 , and T. Kuehl 2,3 1 LASERIX-CLUPS, LIXAM UMR 8624, Universit´ e Paris-Sud 11, Bˆ at. 350, F-91405 Orsay Cedex, France; 2 GSI Helmholtzzentrum f¨ ur Schwerionenforschung GmbH, Planckstr . 1, D-64291 Darmstadt, Germa ny; 3 Insti tut f ¨ ur Physik, Johannes Gutenberg-Universit¨ at Mainz, Staudingerwe g 7, D-55128 Mainz, Germany The paper reports on the optimization of a table-top nickel- like molybdenum transient collisionally excited soft x-ray lase r (SXRL) at 18.9 nm, performed by double-pu lse single beam grazing inci dence pumping (DGR IP)[1 ]. This scheme allows for the first time the full control of the pump lase r parameters includi ng the pre-pu lse duration, opti- mally generating the SXRL amplifier under grazing incidence . The singl e beam geome try of colli near doubl e-pul se propagation guarantees the ideal overlap of the pre- and main pulse from shot to shot, resulting in a more efficient, highly stab le SXRL ou tput. SXRL ene rgies up to 2.2 µJ are obtai ned with a total pump ener gy less than 1 J for sev eral hours at 10 Hz repet ition rate without re-alig nment under once optimized double pumping pulse parameters includ- ing energy ratio, time delay, pre- and main pulse duration and line focus width. Figure 1: The insert box shows the creation of the chirped doubl e-puls e, which is amplifie d and compres sed. The double-pulse is then focused by a spherical mirror in a line onto the target, generating the SXRL beam propagating to the far-field diagnostic on the right or by a backreflection to the near-field diagnostic on the left. In the laser plasma produced soft x-ray laser (SXRL) de- velopment, important steps were made to increase the ef- ficiency of soft x-ray laser generation by introducing the transient collisional excitation scheme with traveling-wave pumping [2], non-normal incidence pumping [3] and grazing inciden ce pumping (GR IP) [4]. Up to now , using the suitable configuration, saturated lasing at wavelengths as low as 11 nm was observed [5], [6], enabling SXRL oper - ∗ [email protected] ation at repeti tion rates of 10 Hz [7]. Rece ntly the double- pulse non-normal incidence pumping geometry joined all the important pumping principles to one more reliable and stab le single beam pumpi ng scheme [8], simi lar to [9], [10 ], [6]. In this paper an ada pte d ve rsi on of the single beam pumping scheme in grazing incidence is carried out for 10 Hz operation, showing higher efficie ncy and prov- ing its perfect suitability for high repetition rate soft x- ray lasers, and givi ng a promis ing outlook for its appli ca- tion in eve n higher repetit ion rate operatio n up to 100 Hz [11],[12]. In con clu sio n the int roduct ion of the DGR IP sch eme impro ves the effi cienc y and stab ility of table -top high- repetition soft x-ray lasers. This result s hows t he attracti ve- ness of this pumping scheme for high average power operation. On one hand the low co sts and the easy and rapi d alignment procedure fulfill the requirements for a sophisti- cated installation, and on the other hand the highly stable output, compared to the jittering output of previous systems, satisfies the need for a reliable strong SXRL source. As an outlook, this system proves to be a milestone for the introduction of multiple pulse capability in Ti:sapphire CPA laser systems for future experiments. Please find more information in [1]. References [1] Zimmer , D. et al., Opt Lett. 35, 450 (2010) [2] Nickles, P . V . et al., Phys. Rev. Lett. 78, 2748 (1997) [3] Neumayer, P . et al., Appl. Phys. B 78, 957 (2004) [4] Keenan, R.; et al., Phys. Rev . Lett. 94, 103901 (2005) [5] Rocca, J. J. et al., Opt. Lett. 30 , 2581 (2005) [6] Gruenig, M. et al., Optics Communications 282 , 267 (2009) [7] Casso u, K.; et al., Opt. Lett. 32, 139 (200 7) [8] Zimmer , D. et al., Opt. Express 16, 1039 8 (2008) [9] Kawac hi, T. et al., App l. Opt. 42, 2198 (200 3). [10] Kim, H. T. et al., Phys . Rev . A 77, 023807 (2008). [11] Tue mmler , J. et al., Opt. Lett. 34, 1378 (2009 ) [12] Furch, F . J. et al., Opt. Lett. 34, 3352 (200 9) GSI SCIENTIFIC REPORT 2009 PLASMA-PHYSICS-16 401

d. zimmer et al- table-top high repetition rate soft x-ray laser pumped in double-pulse single beam...

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