Emerging terawatt picosecond CO₂ laser technology and possible applications in accelerator physics

The first terawatt picosecond (TWps) CO₂ laser is under construction at the BNL Accelerator Test Facility (ATF). TWps-CO₂ lasers, having the order of magnitude longer wavelength than the well-known table-top terawatt solid state lasers, offer new opportunities for the strong-field physics research. For processes based on electron quiver motion, such as laser wakefield acceleration (LWFA), the advantage of the new class of lasers is due to a gain of two orders of magnitude in the ponderomotive potential for the same peak power. The large average power capability of CO₂ lasers is important for the generation of hard radiation through Compton back-scattering of the laser off energetic electron beams, as well as for other applications. Among them are: LWFA modules of a tentative electron-positron collider, γ-γ (or γ-lepton) collider, a possible `table-top' source of high-intensity x-rays and gamma rays and the generation of polarized positron beams.