Optical thresholding and switching using a fiber-coupled phase-conjugate mirror

A fiber-coupled-ring passive phase-conjugate mirror is used to achieve mutual thresholding free of bistability effects and to obtain switching among several mutually incoherent light beams

Theory of intracavity-pumped photorefractive phase-conjugate mirror

We present a new type of phase-conjugate mirror that is based on an externally driven Fabry-Perot interferometer with intracavity-pumped photorefractive material, which is probed by the signal beam. It is shown theoretically that such a configuration leads to multivalued solutions and possibly to bistability. This configuration also permits optical control of the resonator output and electrical control of the phase-conjugate reflectivity

Conductance Phases in Aharonov-Bohm Ring Quantum Dots

The regimes of growing phases (for electron numbers N~0-8) that pass into regions of self-returning phases (for N>8), found recently in quantum dot conductances by the Weizmann group are accounted for by an elementary Green function formalism, appropriate to an equi-spaced ladder structure (with at least three rungs) of electronic levels in the quantum dot. The key features of the theory are physically a dissipation rate that increases linearly with the level number (and tentatively linked to coupling to longitudinal optical phonons) and a set of Fano-like meta-stable levels, which disturb the unitarity, and mathematically the change over of the position of the complex transmission amplitude-zeros from the upper-half in the complex gap-voltage plane to the lower half of that plane. The two regimes are identified with (respectively) the Blaschke-term and the Kramers-Kronig integral term in the theory of complex variables.Comment: 20 pages, 4 figure