We recently showed theoretically that dynamic carrier heating effects are critical to the stability an intraband gain saturation of semiconductor lasers even at room temperatures. This is true, for example, with one of the simplest compounds, GaAs, where a hierarchy of relaxation times exists. At this time there is remarkably little known about the interplay of dynamics associated with carrier heating effects and transverse effects together. Having targeting those systems with a quasi-independent subsystem of energy levels we shall continue our studies of fast processes taking into account electron, hole and lattice temperatures, in less restrictive regimes of the plane- wave model. We have dynamical equations of motions that describe the evolution of the semiconductor laser output beam and its characteristics transverse profile; however, the numerical development is, to date, incomplete and is included as a first phase of this program. Experience and sensitivity to the difficulties in modeling transverse effects in dynamical systems is established in our group and can be used effectively to develop appropriate numerical integration schemes for this problem. Computer methods are on line to analyze various nonlinear phenomena associated with spatio-temporal aperiodic or periodic fields. We will conduct a comprehensive research program on the stability and dynamics of semiconductor lasers distinguished by their quasi-independent subsystem of energy levels. The role that new degrees of freedom play in the generation of complex waveforms including, for example, hysteresis or bistable operation and linewidth of the laser will be addressed. The investigations will lead to the development of novel, compact laser sources with wide applicability in optical devices and systems. Experimental programs designed to accommodate this timescale have only recently become possible through the development of femtosecond lasers. We are exploring possibilities of demonstrating these effects with an external group.
