Antonio Politi — CNR - ISC, sezione di Sesto Fiorentino #
Quasi-Hamiltonian dynamics of laser systems #
A well known mathematical model of laser dynamics is revisited in the limit of a very fast relaxation of the atomic polarization (typical condition offered by fiber and semiconductor lasers). Direct simulations are unfeasible because of the multiple time scales, while a standard adiabatic elimination gives rise to unphysical divergences. I show that the theoretical failure is due to the closeness of the dynamics to a Hamiltonian model: a nonlinear wave equation of Klein-Gordon type accompanied by an exponential (Toda) potential. The additional presence of a perturbative forcing and dissipative terms is eventually responsible for the selection of the energy.