Wavelength Tunable Visible Picosecond Laser

C53-12a-271184Photocathodes are critical for generation of high-brightness electron beams in accelerators that are used in science, industry, and medical disciplines. A visible wavelength-tunable picoseconds laser is required to support optimization of photocathodes leading to more compact, high-performance, and cost-effective systems. Such lasers are not available commercially. With new sources of high-brightness electron beams affordable for universities, commercial laboratories (e.g., semiconductor material development), and hospitals, the US would be able to maintain its technological leadership. In Phase I, we constructed a proof-of-principle Demonstrator system and experimentally validated our concept. We demonstrated key parameters targeted by the DOE including wavelength tunability from 484 to 643 nm, pulse energy up to 425 µJ, and output bandwidth as low as 1 nm. We characterized the performance of the demonstrator system, anchored our predictive models, confirmed energetics, validated the pulse synchronization, and used these results to design the Phase II Prototype driver. Our accomplishments generated an interest by the researchers at a DOE laboratory. In Phase II, we will develop and characterize a prototype photocathode drive laser meeting the DOE functional requirements. Results of Phase I will be extended using our validated approach. Effective thermal management will be implemented for the PA, harmonic conversion crystals, and the OPA crystals to facilitate continuous operation at high-average power. Wavelength selection under computer control with a feedback loop will be created. Means for pulse selection and generation of the objective waveform will be developed. Pulse synchronization at picosecond level will be matured. Spatial pulse shaping will be provided. Temporal pulse shaping will be evaluated. The resulting laser system will be a full-scale prototype offering a direct path to a photocathode drive laser deliverable in Phase III. Commercial applications for a tunable high-average power laser based on the Aqwest concept include science, remote environmental sensing (illuminator for active hyperspectral imaging), and industrial laser material processing.