Reflection of light from a disordered medium backed by a phase-conjugating mirror
J.C.J. Paasschens, M. J. M. de Jong, Piet W. Brouwer +1 more
This is a theoretical study of the interplay of optical phase conjugation and multiple scattering. We calculate the intensity of light reflected by a phase-conjugating mirror when it is placed behind a disordered medium. We compare the results of a fully phase-coherent theory with those from the theory of radiative transfer. Both methods are equivalent if the dwell time ${\ensuremath{\tau}}_{\mathrm{dwell}}$ of a photon in the disordered medium is much larger than the inverse of the frequency shift $2\ensuremath{\Delta}\ensuremath{\omega}$ acquired at the phase-conjugating mirror. When ${\ensuremath{\tau}}_{\mathrm{dwell}}\ensuremath{\Delta}\ensuremath{\omega}\ensuremath{\lesssim}1$, in contrast, phase coherence drastically affects the reflected intensity. In particular, a minimum in the dependence of the reflectance on the disorder strength disappears when $\ensuremath{\Delta}\ensuremath{\omega}$ is reduced below $1/{\ensuremath{\tau}}_{\mathrm{dwell}}.$ The analogies and differences with Andreev reflection of electrons at the interface between a normal metal and a superconductor are discussed.
arXiv:physics/9708010•Physical Review A•Nov 1, 1997•16 citations