A.F.J. Levi
Departments of Electrical Engineering and Physics,
University of Southern California
September 14, 2009
Fluctuations in electron and photon number play an important role in determining the behavior of a laser diode. For example, in large devices containing many particles, conventional Landau-Ginzburg theory of phase transitions predicts fluctuations in photon number enhance lasing below threshold. These fluctuations are of practical importance because, among other things, they contribute to the temperature dependence of laser threshold.
The modern ability of nanophotonics to scale laser diode dimensions suggests one should study the role of particle fluctuations in small laser diodes. To capture the physics dominating such meso-scale devices, master equations can be used to quantize particle number. In the meso-scale regime, correlated quantum fluctuations, and the fact that a lowest energy state of the system exists, can result in suppression of lasing, enhancement of spontaneous emission, and creation of a non-Poisson probability distribution for n discrete excited electronic states and s discrete photons. Dynamic switching between two characteristic system states dominates these fluctuations.