Is there a linewidth theory for semiconductor lasers?

Semiconductor laser generation begins at a critical injection when the gain and loss spectra touch each other at a singular frequency. In the framework of the standard (Schawlow-Townes-Lax-Henry) theory, the finite linewidth results from the account of fluctuations associated with the random spontaneous emission processes. This approach is based on the assumption that in the mean-field approximation the singular frequency generation persists for injection levels higher than critical. We show that this assumption in the framework of the Boltzmann kinetic equation for electrons and photons is invalid and therefore the standard description of semiconductor laser linewidth lacks theoretical foundation. Experimental support of the standard theory is also questionable

Transport in Two Dimensional Electronic Micro-emulsions

In two dimensional electron systems with Coulomb or dipolar interactions, a direct transition, whether first or second order, from a liquid to a crystalline state is forbidden. As a result, between these phases there must be other (microemulsion) phases which can be viewed as a meso-scale mixture of the liquid and crystalline phases. We investigate the transport properties of these new electronic phases and present arguments that they are responsible for the various transport anomalies that have been seen in experiments on the strongly correlated 2DEG in high mobility semiconductor devices with low electron densities

Mesoscopic effects in superconductor-ferromagnet-superconductor junctions

We show that at zero temperature the supercurrent through the superconductor - ferromagnetic metal - superconductor junctions does not decay exponentially with the thickness $L$ of the junction. At large $L$ it has a random sample-specific sign which can change with a change in temperature. In the case of mesoscopic junctions the phase of the order parameter in the ground state is a random sample-specific quantity. In the case of junctions of large area the ground state phase difference is $\pm \pi/2$.Comment: 4 pages, 1 figur