An analytical study of non-resonant transient cross-beam power transfer relevant to recent progress in plasma photonics

Recent experimental and theoretical results have shown that crossing a probe laser in a plasma with a secondary pump can modify the amplitude, phase, and polarization of the probe in a controlled manner. Beyond fundamental physics, these results suggest that a pump-plasma based optical system could be used to amplify and control a laser pulse at high power, where the high fluence precludes using an optical system. This paper attempts to clarify the transient regime of such a pump-probe-plasma system. An analytical solution is derived to the coupled equations in the relevant regime, valid for any frequency detuning, coupling strength, and damping. Asymptotic expressions in the scantly studied off-resonance regime are derived. The time to reach the steady state is found to be roughly independent of the detuning. This time-to-steady-state defines the response time of such a plasma photonics system and can be made potentially much faster than traditional optics by controlling the damping of plasma acoustic waves. We comment on the steady-state assumption typically used to interpret current experiments and design future ones.Recent experimental and theoretical results have shown that crossing a probe laser in a plasma with a secondary pump can modify the amplitude, phase, and polarization of the probe in a controlled manner. Beyond fundamental physics, these results suggest that a pump-plasma based optical system could be used to amplify and control a laser pulse at high power, where the high fluence precludes using an optical system. This paper attempts to clarify the transient regime of such a pump-probe-plasma system. An analytical solution is derived to the coupled equations in the relevant regime, valid for any frequency detuning, coupling strength, and damping. Asymptotic expressions in the scantly studied off-resonance regime are derived. The time to reach the steady state is found to be roughly independent of the detuning. This time-to-steady-state defines the response time of such a plasma photonics system and can be made potentially much faster than traditional optics by controlling the damping of plasma acoustic wa...