Simulation of gain in quantum cascade lasers

Abstract:
The gain profile of a quantum cascade laser is strongly influenced by

the lifetime of the carriers in the upper and lower laser state. The

quantitative description of gain within the concept of nonequilibrium

Green's functions allows for a detailed understanding of various

features affecting the gain spectrum:

Compensation effects between scattering processes in the upper and lower laser

level, reduction of gain due to coherences between nearly degenerate

upper laser states, and dispersive gain without inversion.