Advanced Technologies for Compact 100 W-class Ultrafast Ti:sapphire Lasers to Support DOE Facilities Needs

The development of new DOE ultrashort-pulse x-ray facilities creates exciting new possibilities for understanding dynamic processes in nature on the fundamental atomic length and length scales; i.e. sub- nm and femtosecond. However, to make full use of planned facilities such as the Short Pulse X-ray (SPX) facility planned as a major part of the Advanced Photon Source Upgrade (APS-U), corresponding advances in ultrafast laser technology are necessary to enable the highest possible data collection rates. In this project we address the specific requirement stated in the APS-U Conceptual Design Report for an ultrafast laser amplifier operating at 3-10 milijoules pulse energy, with sub-50 fs pulse duration and highest possible repetition rate. New developments in industrial lasers make it conceptually feasible to implement a Ti:sapphire-based ultrafast laser amplifier with average power approaching and perhaps exceeding 100 W, at a repetition rate that can be varied from10-50 kHz (i.e. 2-10 mJ), with 25-35 fs pulse duration. Thus represents a ~4-5x increase over the average power that can routinely be obtained at present from a compact ti:sapphire laser. The primary objective of this project is to advance ultrafast laser science capabilities through demonstration such of a laser system on a timeline appropriate for APS-U, which is planned for ~2015-6. Given the overall DOE investment in APS-U and the fact that success of the SPX beamline will depend directly on the capabilities of the ultrafast lasers synchronized to the x-ray source, this project represents an excellent advance investment for DOE, with the additional benefit of broad benefit to ultrafast science capabilities. A number of challenges exist for scaling-up the power of ultrafst ti:sapphire lasers to 100 W while still maintaining a compact, semi-transportable and robust laser system. These challenges are summerized as follows: 1) thermal damage and thermal lensing in the laser crystal, Pockels cells and other laser optics; 2) cooling capactiy of cryogenic technology necessary to mitigate thermal issues; and 3) stability and reliability issues for the laser platform in such a high power environment. These challenges will be addressed and a full system design will be finalized in our phase I project. KMLabs is the first company in the world to have commercialized high-power cryogenically cooled lasers, and has unparalleled experience in and intellectual property covering ultrafast Ti:sapphire ampilfier systems technology. We have previously delivered such lasers generating up to 50 W average power, albeit in large and complex laser system. Our goal to obtain 100 W power at up to 50 kHz, while shrinking the laser footprint by ~2x, is thus quite credible. Commercial Applications and Other Benefits: The proposed system has broad application in the field of nonlinear frequency conversion and high field science. This laser system performance goes well beyond what the current state of art system can achieve, so that a broader scientific community in the field of physics, chemistry, and bio-medical science will be benefit from this innovation. This laser system also promises to find significant industrial applications since we propose to focus on the size and robustness of this system as well as its performance.