Visible-Tunable Picosecond
Photocathode Driver
Aqwest is developing an innovative visible wavelength-tunable photocathode drive laser that advantageously combines recent breakthroughs in photonics, existing Aqwest laser technologies, and commercial hardware.
Photocathodes are important in accelerator physics where they are used in photoinjectors to generate high brightness electron beams. Such electron beams are commonly used for research in free electron lasers (FEL), electron beam-driven wakefield acceleration, advanced light sources, colliders, and for ultrafast electron diffraction.
The on-going development of photocathodes for RF accelerators by the U.S. Department of Energy (DOE) continues to improve the photocathode quantum efficiency, low emittance, fast temporal response, long lifetime, storability, and ease of handling. Existing photocathode drivers operating at fixed wavelengths are insufficient to support such research, hence, wavelength-tunable drive lasers are needed. The Aqwest drive laser system targets 100 micro-joules pulse energy, 30 ps pulse length, and 1 MHz pulse repetition rate over a 500-600 nm wavelength range. This research is supported by a grant from the US DOE.
A pre-prototype wavelength-tunable laser using an Aqwest-proprietary architecture recently (November 2022) demonstrated continuous wavelength tuning over the range from 483 to 643 nm and pulse energies up to 425 micro-joules. The wavelength tuning range is extendable to 850 nm.
Prospective alternative applications for visible tunable lasers include wavelength-agile lasers for active remote sensing.
References
- I. Bazarov and L. Cultrera, “Ultra-Low Emittance Photocathodes for Accelerators and Femtosecond Electron Diffraction,” Final Technical Report for DOE Contract DE-SC0014338, 2018.
- T. Rao and D.H. Dowell, “ An Engineering Guide to Photoinjectors,” ISBN-13: 978-1481943222, 2013
- C. Vicario et al., “Photocathode Drive Laser for SWISSFEL,” WEPB14, Proceedings of FEL2010, Malmö, Sweden, 2010