Recent progress in using picosecond CO₂ lasers for Thomson scattering and ion-acceleration experiments underlines their potentials for enabling secondary radiation- and particle- sources. These experiments capitalize on certain advantages of long-wavelength CO₂ lasers, such as higher number of photons per energy unit, and favorable scaling of the electrons' ponderomotive energy and critical plasma density. The high-flux x-ray bursts produced by Thomson scattering of the CO₂ laser off a counter-propagating electron beam enabled high-contrast, time-resolved imaging of biological objects in the picosecond time frame. In different experiments, the laser, focused on a hydrogen jet, generated monoenergetic proton beams via the radiation-pressure mechanism. The strong power-scaling of this regime promises realization of proton beams suitable for laser-driven proton cancer therapy after upgrading the CO₂ laser to sub-PW peak power. This planned improvement includes optimizing the 10-μm ultra-short pulse generation, assuring higher amplification in the CO₂ gas under combined isotopic- and power-broadening effects, and shortening the postamplification pulse to a few laser cycles (150-200 fs) via chirping and compression. These developments will move us closer to practical applications of ultra-fast CO₂ lasers in medicine and other areas.

Date Published: 25 May 2011
PDF: 13 pages
Proc. SPIE 8079, Laser Acceleration of Electrons, Protons, and Ions; and Medical Applications of Laser-Generated Secondary Sources of Radiation and Particles, 80791L (25 May 2011);

Published in SPIE Proceedings Vol. 8079:
Laser Acceleration of Electrons, Protons, and Ions; and Medical Applications of Laser-Generated Secondary Sources of Radiation and Particles
Wim P. Leemans; Kenneth W. D. Ledingham; Eric Esarey; Simon M. Hooker, Editor(s)