Progress of high average power, short-pulse laser technology for the Compton X-ray source

Recent progress is reported in the development of high average power, short-pulse laser technology, which is relevant toward achieving a high X-ray flux in a Compton X-ray source for use in various applications. The Yb-based laser material is suitable for high-pulse energy in a picosecond pulse length. The thin disc amplifier technology is now close to operating continuously with 1 J, 2 ps, at a 100 Hz repetition rate with a multi-pass amplification scheme. The average power is 100 W at a 1030 nm wavelength. The laser beam quality is fine enough to focus on the bunched electron beam from a photocathode/S-band linac single-pass accelerator and to generate an X-ray flux of 109 photons/s at 100 Hz. The short-pulse carbon dioxide (CO2) laser has an advantage for a Compton X-ray source in high X-ray flux applications. The short-pulse amplification of the CO2 laser pulse has been demonstrated, at a power level of more than 10 kW at a 100 kHz repetition rate in a single laser beam, for application in the plasma generation for an extreme ultraviolet light source, using a commercially available RF-pumped laser module. The pulse length is now limited to around 1 ns because of the bandwidth of the low-pressure gain medium. The additional pulse compression scheme makes a high average power, pulsed CO2 laser ideal for various applications of the Compton X-ray source.