Photon echoes as a probe for long-range spatial correlations

Eiichi Hanamura, Shaul Mukamel
1986 Journal of the Optical Society of America. B, Optical physics  
A microscopic correlation-function expression for the photon-echo signal in systems with long-range spatial correlations is developed. In general, the signal is given by an eight-point correlation function of the dipole operator involving two particles. In the absence of long-range spatial correlations, this correlation function may be factorized into a product of two four-point, single-particle correlation functions. Only under these conditions is the signal proportional to the absolute square
more » ... the absolute square of the ensemble-averaged nonlinear polarization. We predict that photon echoes may be used to probe the long-range spatial correlations near critical points.
doi:10.1364/josab.3.001124 fatcat:ln2434yhwjglzpxlc7tlj3y2c4