Generation of relativistic electron mirrors and frequency upconversion in laser–plasma interactions

Abstract

It is shown analytically and by computer simulation that relativistic electron mirrors (bunches with extremely short length) can be generated by an ultra-intense nonadiabatic laser pulse (pulse with a sharp rising edge) incident normally upon a thin rarefied plasma layer provided the cross dimensions of laser beam are large enough. Due to Coulomb forces, the electron mirror is a transient structure that exists as a single whole only during a limited time at the beginning of the laser–plasma interaction. Frequency upconversion of the probe laser pulse into the single, ultrashort, and coherent hard x-ray pulse due to backscattering off such a relativistic electron mirror is also considered and the spectrum of upshifted radiation is investigated.