Coupled-mode analysis of light propagation in optically active crystals

A new mathematical formalism, based on a coupled-mode approach, is presented to describe light propagation in birefringent optically active crystals. An arbitrary light wave in the medium is represented as an expansion in terms of linearly polarized eigenmodes; explicit solutions of the equations for the coupled-wave amplitudes show how power is transferred between the principal components in the presence of optical activity. The (generally elliptically polarized) eigenmodes of the optically active crystal are also derived by a diagonalization of the coupled-mode equations. The analysis is extended to include electro-optic crystals, yielding a more general, complex coupling parameter. The predictions of the theory are in excellent agreement with spectral-transmission measurements in AgGaS2 near its isoindex point at 497 nm

Guided Wave Optics

Phenomena associated with the propagation and manipulation of light in thin-film dielectric waveguides are presently the object of considerable research effort, directed toward possible applications in communications and information processing. The theory of dielectric waveguide modes is reviewed, and the topics of directional coupling, input-output coupling, modulation, and distributed feedback laser sources are treated on the basis of coupled-mode theory. A summary of experimental results for each of the guided-wave optical phenomena covered by the theory is also presented

A Parallel Analog CCD/CMOS Signal Processor

A CCO based signal processing IC that computes a fully parallel single quadrant vector-matrix multiplication has been designed and fabricated with a 2μm CCO/CMOS process. The device incorporates an array of Charge Coupled Devices (CCO) which hold an analog matrix of charge encoding the matrix elements. Input vectors are digital with 1 - 8 bit accuracy

Spatial Light Modulators As Parallel Memories For Optoelectronic Neural Networks

A generic architecture for realizing neural networks is presented in which the synaptic interaction matrix is loaded in parallel into an electronic integrated circuit from a SLM. Three types of the electronic processors are described using CCD, CID and CMOS technologies respectively. The pros and cons of currently existing SLMs for this architecture are pointed out

Spatial Light Modulators As Parallel Memories For Optoelectronic Neural Networks

A generic architecture for realizing neural networks is presented in which the synaptic interaction matrix is loaded in parallel into an electronic integrated circuit from a SLM. Three types of the electronic processors are described using CCD, CID and CMOS technologies respectively. The pros and cons of currently existing SLMs for this architecture are pointed out

The Sagnac effect in Coupled-Resonator Slow-Light Waveguide Structures

We study the effect of rotation on the propagation of electromagnetic waves in slow-light waveguide structures consisting of coupled micro-ring resonators. We show that such configurations exhibit new a type of the Sagnac effect which can be used for the realization of highly-compact integrated rotation sensors and gyroscopes

Magnetic anisotropies and general on--site Coulomb interactions in the cuprates

This paper derives the anisotropic superexchange interactions from a Hubbard model for excitations within the copper 3d band and the oxygen 2p band of the undoped insulating cuprates. We extend the recent calculation of Yildirim et al. [Phys. Rev. B {\bf VV}, pp, 1995] in order to include the most general on--site Coulomb interactions (including those which involve more than two orbitals) when two holes occupy the same site. Our general results apply when the oxygen ions surrounding the copper ions form an octahedron which has tetragonal symmetry (but may be rotated as in lanthanum cuprate). For the tetragonal cuprates we obtain an easy--plane anisotropy in good agreement with experimental values. We predict the magnitude of the small in--plane anisoComment: 25 pages, revte

Long-term studies of hemoglobin-oxygen affinity in hypoxemic dogs with a right-to-left cardiac shunt

Long-standing hypoxemia was surgically created in dogs by inserting an aortic homograft between the inferior vena cava and right atrium. Ligation of the caval--atrial junction resulted in a right-to-left cardiac shunt. Arterial p O2 fell immediately and P50 increased within 20 min. The 2,3-diphosphoglycerate concentration rose in 4 hr following surgery, while hemoglobin concentration increased within 7 days. Alterations in hemoglobin--oxygen affinity can occur rapidly and may be beneficial compensatory responses to acute and chronic hypoxemia caused by a right-to-left cardiac shunt.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23370/1/0000314.pd

Quantized adiabatic charge pumping and resonant transmission

Adiabatically pumped charge, carried by non-interacting electrons through a quantum dot in a turnstile geometry, is studied as function of the strength of the two modulating potentials (related to the conductances of the two point-contacts to the leads) and of the phase shift between them. It is shown that the magnitude and sign of the pumped charge are determined by the relative position and orientation of the closed contour traversed by the system in the parameter plane, and the transmission peaks (or resonances) in that plane. Integer values (in units of the electronic charge $e$) of the pumped charge (per modulation period) are achieved when a transmission peak falls inside the pumping contour. The integer value is given by the winding number of the pumping contour: double winding in the same direction gives a charge of 2, while winding around two opposite branches of the transmission peaks or winding in opposite directions can give a charge close to zero.Comment: 7 pages, 12 figure