Excitation of a triad artificial photosynthetic reaction center consisting of a porphyrin (P) convalently linked to a fullerene electron acceptor (C60) and a carotenoid secondary donor (C) leads to the formation of a long-lived C.+-P-C60.- charge-separated state via photoinduced electron transfer. This reaction occurs in a frozen organic glass down to at least 8 K. At 77 K, charge recombination of C.+-P-C60.- occurs on the νs time scale, and yields solely the carotenoid triplet state. In the presence of a small (20mT) static magnetic field, the lifetime of the charge-separated state is increased by 50 %. This is ascribed to the effect of the magnetic field on interconversion of the singlet and triplet biradicals. At zero field, the initially formed singlet biradical state is in equilibrium with the three triplet biradical sublevels, and all four states have comparable populations. Decay to the carotenoid triplet only occurs from the three triplet sublevels. In the presence of the field, the S and T?0? states are still rapidly interconverting, but the T+ and T- states are isolated from the other two due to the electronic Zeeman interaction, and are not significantly populated. Under these conditions, recombination to the triplet occurs only from T0, and the lifetime of the charge-separated state increases. This effect can be used as the basis for a magnetically controlled optical or optoelectronic switch (e.g. AND gate).

Magnetic switching of charge separation lifetimes in artificial photosynthetic reaction centers

An apparatus and method for a switch for a radiation signal. The switch includes a first waveguiding channel having a guiding region and one or more bounding regions coupled to the guiding region, the first waveguiding channel including a first lateral guiding port in a portion of the bounding regions, the lateral guiding port responsive to an attribute of radiation propagating in the channel to selectively pass a portion of the radiation therethrough; and an influencer, coupled to the first waveguiding channel, for controlling the attribute of the radiation. A method of operating the switch includes: a) propagating the radiation signal in a first waveguiding channel having a guiding region and one or more bounding regions coupled to the guiding region, the first waveguiding channel including a first lateral guiding port in a portion of the bounding regions, the lateral guiding port responsive to an attribute of radiation propagating in the channel to selectively pass a portion of the radiation therethrough; and b) influencing the radiation signal in a portion of the guiding region to control the attribute wherein a first value of the attribute passes a first amplitude for the radiation signal and a second value of the attribute passes a second amplitude for the radiation signal.

Apparatus, method, and computer program product for transverse waveguided display system

Disclosed is a solid state apparatus for and a method of (1) modulating the intensity of a multimode light beam; (2) coupling the light beam to an input optic fiber that is butt coupled to a diffraction grating that is formed of a plurality of stripe domains in a magnetic film; (3) altering, by the application of suitable magnetic fields, the angular orientation of the stripe domains in the plane of the magnetic film, and (4) multiplexing the diffracted light beam to a selected one of a plurality of several output optic fibers. The apparatus uses a liquid-phase epitaxially (LPE) grown film of bismuth substituted rare earth iron garnet to form a magnetizable layer in which stripe domains may be generated, sustained and moved about. The stripe domains form a diffraction grating. The angular orientation of the stripe domains in the plane of the diffraction grating may be altered by the application of external magnetic fields -- see the E. J. Torok, et al, U.S. Pat. No. 3,752,562 -- to alter the angle from which the diffracted light beam is emitted from the diffraction grating. The altered or rotated stripe domains are, in turn, utilized to alter the direction that the deflected light beam is emitted from the diffraction grating and into, along and out of a selected one of a plurality of output optic fibers that are oriented along the surface of an inverted cone, which cone is aligned, along its longitudinal axis, with the optic axis of the input optic fiber.

Multimode optic device

The invention relates to non-linear optical devices in which significant non-linear interactions are obtained by establishing a "quasi phase matching". The optical device according to the invention comprises on the surface of a substrate a periodic structure formed of zones in which the non-linear coefficient alternately assumes two values of opposite signal. The invention also relates to a process for producing this device. The invention allows generation of harmonics, frequency changing, parametric amplification or parametric oscillation.

Non linear thin layer optical device

A system and method are disclosed for an optical backplane in an electronic processor that comprises of a plurality of processing units. The backplane is comprising of a network of optical waveguides which can guide polarized light. Furthermore, the backplane has magneto optic routers for steering light at the vertexes of the network, and the backplane also has optical devices for operationally connecting the processing units to the network. The backplane network affords an optical interconnection amongst all of the processing units.

Magneto-optical switching backplane for processor interconnection

A switching device for switching an optical beam between first and second outputs each associated with first and second paths in a thin-film optical wave guide supported on a substrate. Switching occurs by reason of mode conversion in a first or second path as determined by the direction of a variable magnetic field. A common optical path is defined, in said wave guide, by a first optical coupler, for coupling an optical beam into or out of said wave guide, and a beam splitter. First and second optical paths are defined, in the same wave guide, between the beam splitter and second and third couplers each co-linear with said beam splitter. At least a portion of each of said first and second optical paths include means for periodically varying the magnetization in said path. The wave guide is subjected to a d.c. magnetic field in the plane of the wave guide and at an angle with respect to both said first and second paths. Preferably the first and second paths are perpendicular and the d.c. field makes a 45° angle with each of said paths. A variable magnetic field is superimposed on the d.c. field and is directed perpendicular to the d.c. field, in the plane of the wave guide. The variable magnetic field may be energized in one of two senses, 180° apart, each, of course, perpendicular to the d.c. field direction. Analyzers may be located adjacent the second and third couplers to comprise the outputs referred to above.

Samuel C.-C. Tseng

Papers

Magneto-optical digital light deflector

Dispositif de commutation de faisceau optique