Laser energy absorption in gases - Research problems

A review is presented of the current state of knowledge of laser energy absorption in gas engines, such as laserpowered rockets. Absorption for both continuous wave (CW) and pulsed engines are considered. For CW engines, absorption by laser-supported combustion (LSC) waves and by molecular resonance are possible mechanisms. For pulsed engines, laser-induced breakdown is a crucial element. As a result of this review, areas for further research are identified. They include the structure of seeded LSC waves, low temperature molecular absorbers, bleaching and multiphoton effects on molecular absorption, laser-induced breakdown in the visible/UV wavelength region, the stability of CW absorption processes, and possible mode-media interaction effects.