High power diode-pumped laser amplifier for laser-driven ultrafast table-top soft x-ray laser sources

The problem/situation that is being addressed is the development and improvement of compact laser- driven x-ray sources for ultrafast characterization of interest to the DoE. While much progress has been made in the development of table-top x-ray sources, with high harmonic sources and atomic soft x-ray lasers presently allowing for a large number of experiments to be conducted in small laboratories, their average power remains small compared with that of free electron lasers (FELs). Plasma-based table-top soft x-ray lasers can generate a large number of photons per pulse. However, the lasers currently used to pump them operate at low repetition rate, severely limiting their potential to generate high average powers. This limitation is the result of deleterious thermal effects in the flash-lamp pumped lasers used to heat the plasmas. How we propose to address the problem/ situation is to develop a high repetition rate, high average power, diode pumped ultra-short pulse Yb:YAG laser amplifier with the specifications necessary to drive table-top soft x-ray lasers at an unprecedented repetition rate of 1 kHz, enabling the table-top generation of multi-mW average power laser beams at photon energies neighboring 100 eV. The proposed laser will also be ideal to pump optical parametric chirped pulse amplifiers (CPA) producing high average power trains of high energy femtosecond pulses to drive high harmonic x-ray sources and intense ultrafast incoherent hard x-ray plasma sources. In this project we plan to build upon high pulse energy diode-driven solid state cryogenic laser amplifier technology developed at CSU, that recently produced 1 J laser pulses of picosecond duration at 100 Hz repetition rate, a world record for CPA lasers. The goal of this proposal is to further advance this technology to develop a compact diode pumped laser capable of generating picosecond pulses of > 1 J energy at 1 KHz repetition rate. In Phase I we propose to demonstrate the feasibility of the approach by conducting gain measurements in an amplifier module and performing model simulations. We also propose to complete a preliminary design of the laser system that will be constructed, tested, and packaged as the main deliverable in Phase II. Commercial Applications and Other Benefits: The primary application of the proposed high energy, high repetition rate, diode-pumped laser is to drive high average power table-top plasma-based atomic soft x-ray lasers. However, its modular architecture will allow its use in several other applications that include pumping high average power femtosecond optical parametric chirped-pulse amplification lasers for high pulse energy high harmonic x-ray sources, intense incoherent ultrafast hard x-ray generation, and materials processing. Lasers capable of delivering high energy pulses of picosecond duration at kHz repetition rate are not commercially available at the present time.