Transient lasing without inversion via forbidden and virtual transitions

Luqi Yuan, Dawei Wang, Anatoly A. Svidzinsky, Hui Xia, Olga Kocharovskaya, Alexei Sokolov, George R. Welch, Szymon Suckewer, and Marlan O. Scully

Phys. Rev. A 89, 013814 – Published 13 January 2014

Abstract

Lasing without inversion (LWI) in the extreme-ultraviolet (XUV) has been the focus of recent research of our Princeton/Texas group. Because of the restriction imposed on the decay rates associated with the usual LWI schemes, it is difficult to transfer the physics gleaned from previous experiments to the XUV. However, with the advent of tunable-ultrashort-high-power laser pulses, we find that the possibility of transient LWI holds promise for a different LWI paradigm in which the lasing is based on forbidden and/or virtual transitions. It is the purpose of the present paper to present simple but (hopefully) convincing arguments and suggest realistic experiments to stimulate interest in this idea.