Massachusetts Institute of Technology

Other

Lockheed Sanders, Inc.

Robert D Meade

John Dimitris Joannopoulos

Shanhui Fan

Pierre R Villeneuve

Karl D Brommer

Henry Mullaney

Andrew Rappe

Oscar L Alerhand

John Joanopoulos

The present invention provides a resonant cavity including a planar two-dimensional periodic dielectric structure which exhibits a photonic band gap and a defect in the periodic dielectric structure which results in an electromagnetic mode within the photonic band gap. The photonic band gap effects an in-plane spacial confinement of electromagnetic radiation generated within the structure. The electromagnetic radiation is vertically confined by total internal reflection.

Resonant cavities employing two dimensionally periodic dielectric

The present invention provides a resonant microcavity which includes a periodic dielectric waveguide, and a local defect in the periodic dielectric waveguide which accommodates spacial confinement of radiation generated within the waveguide around the defect. In an alternative embodiment, the present invention provides a method of enhancing radiation confinement within a resonant microcavity and minimizing radiation losses into an associated substrate, the microcavity configured within a periodic dielectric waveguide as a local defect which exhibits spacial radiation confinement, the method including the step of increasing the refractive index contrast between the microcavity and the substrate.

Resonant microcavities employing one-dimensionally periodic dielectric

The arm protector head rest is a half cylindrical shaped head rest with an outer and inner surface having a soft foam wall body. The head rest has support ridges of integral skin polyurethane foam on the inner surface sufficient to support the weight of a person's head when resting. A passageway exists between the inner surface and the bed such that a person may place their arms under the head rest and thereby under the resting head without the weight of the head on the arms. An alternate head rest uses U-shaped ribs in the wall to provide the structural support for the weight of the head.

Reinforced arm protector head rest

A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, at least one layer having a stratum of a first material having a first dielectric constant and a plurality of parallel regions along a first axis lying in the plane of the layer, the regions including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.

Three-dimensional periodic dielectric structures having photonic bandgaps

An optical circuit and a method for substantially eliminating radiation losses associated with optical integrated circuits and, in particular, bends in optical waveguides, is disclosed. The circuit and waveguide are fabricated on a substrate having a periodic dielectric structure. The periodic dielectric structure exhibits a range of frequencies of electromagnetic radiation which cannot propagate into the structure. The range of frequencies is known as a photonic band gap or frequency band gap. Radiation at a frequency within the frequency band gap of the structure is confined within the circuit and waveguide by the periodic dielectric structure surrounding the circuit and waveguide. Radiation losses are substantially eliminated.

Optoelectronic integrated circuits and method of fabricating and

Low-loss dielectric resonant devices having lattice structures with

A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, each layer having a stratum of a first material having a first dielectric constant and a plurality of parallel grooves along a first axis lying in the plane of the layer, the grooves including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.

A filter utilizes a frequency selective, non-conductive, dielectric structure for filtering electromagnetic energy in the millimeter to far infrared frequency bands. The filter includes a non-conductive, high-dielectric, background material positioned to receive incident electromagnetic energy. A lattice structure comprised of a plurality of elongated elements formed of a non-conductive, high-dielectric material are disposed in a two-dimensional, periodic arrangement in the background material. The elements extend in parallel to one another through the background material for providing a range of frequencies over a band gap in which incident electromagnetic energy within the frequency range of the band gap is substantially prevented from propagating through the lattice structure. The dielectric structure can be adapted to operate as a band stop filter or a low pass filter.

Filter utilizing a frequency selective non-conductive dielectric

A dielectric resonator comprising a resonant defect structure disposed in a lattice structure formed of a plurality of multi-dimensional periodically arranged dielectric elements confines electromagnetic energy within a frequency band in the photonic band gap. The frequency band of the confined electromagnetic energy is tunable. The unique structure of the dielectric resonator leads to reduced power dissipation losses when used in microwave and millimeter wave components. Accordingly, the dielectric resonator

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Westfield, NJ, United States of America

Robert D Meade