Role of rotational coherence in femtosecond-pulse-driven nitrogen ion lasing

Abstract

The authors experimentally investigated the rotationally resolved polarization characteristics of nitrogen ion lasing using a pump-seed scheme. The paper finds that the polarization of P and R branches lasing exhibit abnormal dependence on the angle between the polarizations of the pump and the seed. The underlying mechanism is ascribed to the cascaded Raman processes following ionization.