Laser Systems Development for the International Linear Collider (ILC) Photoinjector

The International Linear Collider is a proposed 40 km-long electron accelerator that will enable the exploration of the high-energy frontier in particle physics. The electron source for the ILC is a laser-driven photocathode, and the primary unproven part of this technology is the development of a laser with the required pulse characteristics and average power. This project will develop a laser system capable of generating pulse bursts of coherent ~800 nm light with the following characteristics: (1) ~5 µJ of energy in each pulse, (2) a 3 MHz repetition rate, and (3) 2820 pulses in each individual burst. The technical approach involves the development of an oscillator-amplifier laser system based on a titanium-doped sapphire in the required wavlength range. ILC power requirements also dictate the use of a cryogenically-cooled laser medium and 50-100W of "pump" light to power the amplifier. In Phase I, a test bed was constructed to measure single pass gain, mode quality, and energy of a high repetition rate, cw-pumped amplifier laser system at 3 MHz, at repetition rates between 10-250 kHz. Phase II will design, construct, test, and install a fully functional prototype titanium-doped sapphire oscillator-amplifier laser system. Commercial Applications and Other Benefits as described by the awardee: The pulsed laser system should provide unprecedented repetition-rate and average-power characteristics for the ILC application. In addition to the ILC, the laser should find use in both basic science (e.g., for high-fidelity studies of materials and molecular dynamics) and industrial and medical applications (such as precision laser machining).