Semi-classical theory of swept-gain amplification

J.A. Hermann

C. M. Bowden, F. P. Mattar

Crispin W. Gardiner, Matthew J. Collett

Chul Min Kim, Jongmin Lee, Karol Adam Janulewicz

A one-dimensional model of the coherent amplification in a high- and swept-gain amplifier in the presence of strong spontaneous emission is presented and applied to seeding an x-ray laser with a high harmonic pulse. The atomic structure of the amplifying medium includes level degeneracy, and the Maxwell-Bloch equations are used to describe the propagation and interaction processes. This analysis elucidates, in the most comprehensive way, the influence of the random spontaneous emission on the coherent amplification process, as reflected in the basic pulse parameters such as its shape, polarization, and coherence.

J.A. Hermann

Linear analytic solutions of the homogeneously broadened, unidirectional Maxwell-Bloch equations with field losses are found in circumstances where amplification can occur. Particular stress is laid upon the similarity-variable solution. A number of inequalities are derived which suffice to differentiate between the physical regimes of superfluorescence, amplified spontaneous emission and swept-gain amplification.

F. A. Hopf, Pierre Meystre, David W. McLaughlin

Small-signal-pulse growth in a homogeneously broadened amplifier with swept gain is discussed from a quantum-mechanical and a semiclassical treatment. The regime in which Beer's law fails is discussed analytically. There we find nonexponential growth and the formation of steady states in the small-signal regime.