Aaron S. Manka

Quantum theory of laser emission from driven three-level atoms

Abstract We develop a quantum mechanical theory of a three-level laser driven by a coherent external field following the conventional Scully-Lamb approach. We study both the transient and steady state behaviors of this system and focus, in particular, on the statistical fluctuations of the cavity field. For selected values of the parameters the radiated field shows strong sub-poissonian characteristics.

Pulse propagation in a Raman pumped, four-level medium that exhibits inversionless gain

Abstract We numerically study the effect of two, coherent, copropagating pulses incident on an atomic beam of identical, homogeneously broadened, four-level atoms. The injected pulses have different frequencies that are nearly resonant with the allowed dipole transitions. The complex polarization that gives rise to gain and dispersion is examined at various field strengths; including strong probe field strengths where standard linear treatments are not valid. We conclude that in contrast to the steady state case, the maximum gain decreases at the sidebands with increasing pump strengths. In the nonlinear regime, where pump and probe are of comparable magnitude, competition between the upper and lower coherences may lead to loss of gain.