Physical Review A
Superfluorescence pumped by a short pulse of arbitrary shape
C. T. Lee
Abstract
Recognizing that the complete initial inversion required in superfluorescence (SF) can only be achieved in a finite time, we use two different master equations for two different stages of SF: one describing the initiation of SF during pumping and another one governing the free evolution of SF after pumping. The pumping process is treated as a Poisson process with varying rate to reflect a pump pulse of arbitrary shape. The exact solution to the first master equation is obtained and used as the initial condition for the second master equation. The statistical properties of the tipping angle and the delay time are then calculated explicity. It is shown that the effects of pumping process on these two quantities can be reduced to a parameter called effective head-start time (EHT). Two different expressions for this EHT have been derived: one with saturation effects and another one without.