Propagation of Nonclassical Radiation through a Semiconductor Slab
  Based on a microscopic derivation of the emission spectra of a bulk semiconductor we arrive at a clear physical interpretation of the noise current operators in macroscopic quantum electrodynamics. This opens the possibility to study medium effects on nonclassical radiation propagating through an absorbing or amplifying semiconductor. As an example, the propagation of an incident squeezed vacuum is analyzed. 
D.Yu. Vasylyev, W. Vogel, T. Schmielau, K. Henneberger, D.-G. Welsch