Direct Diode Pumped 100-200kHz (200W) Ti:Sapphire Ultrafast Laser System for Cost Effective EUV Generation in Hollow Waveguides.

Currently, the most successful approach for table-top soft X-ray and EUV (Extreme Ultra-Violet ) sources is that of High Harmonic Generation (HHG), where high intensity pulses are used to drive frequency conversion from a noble gas. This configuration converts the infrared drive laser to photon energies beyond 1.6keV (x-rays). This approach requires extremely short pulses and typically uses Ti:sapphire lasers. These lasers, however, suffer from reliability and stability issues due in large part to their reliance on complex and unreliable green (532nm) pump lasers. This work will address that problem by proving the viability of direct diode pumping for Ti:sapphire amplifiers. Direct diode pumping is widely recognized for reliability in the larger, industrial markets addressed by Yb-doped laser systems but has not been developed for Ti:sapphire. Recently, KMLabs, along with collaborators at the Colorado School of Mines, was successful in demonstrating the worlds first Kerr lens modelocked ultrafast oscillator using 445nm high power blue diodes and ushering in a new era for Ti:sapphire systems. The promise of direct diode pumping is a 5X-10X reduction in pump laser cost and a corresponding increase in reliability. In this Phase II, we will to take the next step in furthering this research to include an amplifier based on direct diode pumping of Ti:sapphire, with an objective of eventually converting the output to the EUV through HHG for BES applications within the DOE. In phase I of this work, we developed a pump module for an ultrafast Ti:sapphire laser oscillator, and demonstrated direct diode pumping of that laser up to powers & gt;300mW. We showed the feasibility of extending this technology to an ultrafast Ti:sapphire amplifier system. In Phase II of this program, we will investigate the details of further amplifying our direct diode pumped Ti:sapphire oscillator up to levels capable of HHG using direct diode pumping of an amplifier also. We will use our patented cryogenic amplifier technology to run this system at high average powers. Commercial Applications and Other Benefits: Traditional Ti:sapphire markets such as 2-photon microscopy, bio-imaging, and OCT continue to grow, but that expansion could be much larger with cost reductions and reliability improvements. Additionally, industries that have relied on Yb based systems (delivering 300-500fs pulse widths) due to the cost and complexity of Ti:sapphire systems (micromachining, ophthalmology, bio-medical), could benefit from the shorter Ti:sapphire pulses. This program seeks to eliminate the cost and reliability issue while enabling very short pulses (20-30 fs) for existing applications, as well as to open new markets for Ti:sapphire lasers.