Intense Mid-Infrared Laser Pulse Generated via Flying-Mirror Red-Shifting in Near-Critical-Density Plasmas

Abstract

Relativistic femtosecond mid-infrared pulses can be generated efficiently by laser interaction with near-critical-density plasmas. It is found theoretically and numerically that the radiation pressure of a circularly polarized laser pulse first compresses the plasma electrons to form a dense flying mirror with a relativistic high speed. The pulse reflected by the mirror is red-shifted to the mid-infrared range. Full three-dimensional simulations demonstrate that the central wavelength of the mid-infrared pulse is tunable from 3 μm to 14 μm, and the laser energy conversion efficiency can reach as high as 13%. With a 0.5–10 PW incident laser pulse, the generated mid-infrared pulse reaches a peak power of 10–180 TW, which is interesting for various applications in ultrafast and high-field sciences.