The Petawatt Field Synthesizer: A new Approach to Ultrahigh Field Generation Stefan Karsch 1 , Zsuzsanna Major 1 ,J´ ozsef F ¨ ul¨ op 1,2 , Izhar Ahmad 1 , Tie-Jun Wang 1 , Andreas Henig 1,2 , Sebastian Kruber 1 , Raphael Weingartner 1,2 , Mathias Siebold 1 , Joachim Hein 3 , Christoph Wandt 1 , Sandro Klingebiel 1 , Jens Osterhoff 1 , Rainer H¨ orlein 1,2 , Ferenc Krausz 1,2 1 Max-Planck-Institut f¨ ur Quantenoptik, Hans-Kopfermann-Str. 1, D-85748 Garching, Germany 2 Ludwig-Maximilians-Universit¨ at M¨ unchen, Am Coulombwall 1, D-85748 Garching, Germany 3 Friedrich-Schiller-Universit¨ at Jena, Max-Wien-Platz 1, D-07743 Jena, Germany stefan.karsch@mpq.mpg.de Abstract: The Petawatt Field Synthesizer (PFS) at MPQ will deliver few-cycle pulses at Petawatt power. Short-pulse OPCPA and a diode-pumped, CPA Yb:YAG pump laser are key technologies, and results of the ongoing development will be presented. © 2007 Optical Society of America OCIS codes: 140.7090, 140.3280 1. Introduction The Petawatt Field Synthesizer (PFS), currently under construction at the Max-Planck-Institut f¨ ur Quantenoptik (Garching, Germany), represents a project for developing a light source for a broad variety of fundamental physics. The PFS light-source is expected to deliver wave-form controlled, few-cycle laser pulses with PW-scale peak power. It will support the generation of single intense attosecond extreme ultraviolet (XUV) pulses by relativistically driven high-harmonic generation on a solid surface. A second key application is driving a stable laser-wakefield accelerator in the “bubble” regime for GeV-scale, monoenergetic electron pulses. Laser pulses with the unique PFS parameters are expected to yield stable electron pulses as well as to increase the accelerated charge. These pulses may then be used for seeding a table-top X-ray free-electron laser [1]. Long-term prospects range from advances in attosecond science over material science and biology, to nonlinear nuclear physics and fundamental high-field interactions. 2. Concept and goals The Petawatt Field Synthesizer light source is designed to deliver phase stabilized few-cycle (∼ 5 fs) laser pulses in the wavelength band between 800 and 1600 nm with an energy of > 3 J and a repetition rate of 10 Hz. The focussed intensity should reach or exceed 10 22 W/cm 2 . In order to achieve these ambitious goals, the PFS design is based on a modified optical parametric chirped pulse amplification (OPCPA) scheme [2]. Traditional OPCPA systems operating with ∼100 ps - ns pulses have already demonstrated to deliver pulse energies as high as 35 J in 84-fs pulses [4] as well as 90 mJ in the few-cycle regime (10 fs) [5]. However, the generation of Joule-scale pulse energies in the few-cycle regime requires a modified approach and has yet to be demonstrated. This is the main aim of the PFS project. In [4], large, relatively narrowband DKDP crystals are used to generate high energy pulses with longer duration, whereas in [5] large bandwidth is achieved through the choice of BBO as the nonlinear crystal. Since BBO or LBO are only available in insufficient size for our goals, in the PFS design an alternative approach is applied. Here, short, high-intensity pulses are used to pump the OPA stages, i.e. on the order of ∼ 1 ps. In this case, the large bandwidth can be obtained from ordinary DKDP crystals with small thickness, while the gain is achieved through high intensity, although in our design we stay safely below the threshold for nonlinear propagation and damage. Our modelling suggests that this is the only viable approach for petawatt-scale few-cycle pulse generation, and, moreover, affords several key advantages for high-quality pulse generation. Firstly, the short pulse duration reduces the stretching factor, leading to high stretching and compression fidelity and allowing the use of simple, high-throughput stretcher- compressor systems, such as bulk glass or chirped mirrors for. Secondly, the short pump-pulse duration results in a dramatic increase of of pulse contrast due to the sub-ps time-window for parametric fluorescence. WF1.pdf © 2008 OSA/ BIOMED/DH/LACSEA 2008 WF1.pdf © 2008 OSA/ ASSP WF1.pdf