Cryogenically-Cooled High Average Power Picosecond Ytterbium Lasers

The electron source at the front end of modern accelerators, also know as an electron ¿gun,¿ is a laser-driven photocathode. This technology requires the development of a laser with the required pulse characteristics and average power. This project will develop a compact and robust laser system capable of generating pulses with 1 µm wavelength, 10-100 µJ pulse energy, and tunable pulse width between 10 and 50 ps, at 1-100 MHz repetition rate. The approach will involve the development of a hundred watt, level oscillator-amplifier laser system, based on ytterbium-doped crystals, that operates in the required wavelength range. Phase I will begin with the development an analytical model and numerical codes to determine the limiting factors for high-average-power, cryogenically-cooled mode-locked oscillators. A mode-locked oscillator will be built, and its parameters and performance will be measured. The analytical model and numerical codes will be benchmarked with the measured data before proceeding with the design of the full oscillator-amplifier system, which will be implemented in Phase II. Commercial Applications and other Benefits as described by the awardee: The pulsed laser system should have unprecedented high repetition-rate and high average-power characteristics. In addition to its application to photoinjectors in modern accelerators, the laser also should find uses in basic science (e.g., for high-fidelity studies of materials and molecular dynamics), industry (such as for precision laser micromachining), and medicine.