Electronic noise-free measurements of squeezed light
  We study the implementation of a correlation measurement technique for the characterization of squeezed light. We show that the sign of the covariance coefficient revealed from the time resolved correlation data allow us to distinguish between squeezed, coherent and thermal states. In contrast to the traditional method of characterizing squeezed light, involving measurement of the variation of the difference photocurrent, the correlation measurement method allows to eliminate the contribution of the electronic noise, which becomes a crucial issue in experiments with dim sources of squeezed light. 
Leonid A. Krivitsky, Ulrik L. Andersen, Ruifang Dong, Alexander Huck,   Christoffer Wittmann, and Gerd Leuchs