Nec Research Institute, Inc.

Peter A Wolff

Tineke Thio

Thomas Wren Ebbesen

Hadi F Ghaemi

Stuart A Solin

Mark Lee

A metallic film has apertures located therein in an array arranged in a pattern so that when light is incident on the apertures, surface plasmons on the metallic film are perturbed resulting in an enhanced transmission of the light emitted from individual apertures in the array. The aperture array is used: to filter light of predetermined wavelength traversing the apertures, to collect light over a distance after traversing the apertures, to improve operation of near-field scanning optical microscopes, and to enhance light transmission through masks useable in photolithography.

Near-field scanning optical microscope having a sub-wavelength aperture

Sub-wavelength aperture arrays with enhanced light transmission

A tapered probe tip for use in near-field scanning optical microscopy is coated with a sheath of metal material having a plasma frequency comparable to optical frequencies. Alternatively, the sheath material has lower energy plasmons. The preferred sheath material is silver. Other preferred sheath materials are potassium, Rb, cesium, tungsten oxide, sodium tungsten oxide and Re oxide.

Near-field scanning optical microscope probe exhibiting resonant plasmon

An optical switching device comprises a material which exhibits third order optical nonlinearity (X.sup.(3)) at frequencies just below the band gap of the material, a room temperature and at a wavelength of approximately 1.55.mu.. The switching device is particularly useful for optical communication applications. The preferred material is n-Al.sub.x Ga.sub.1-x Sb, where x is approximately 0.1. Additional preferred materials are those which have a band gap (at .GAMMA.) just above the photon energy of the system and have a subsidiary conduction band (at X or L) approximately 0.1 ev above the E.sub.o level at .GAMMA. at a predetermined wavelength. Such alloy systems include (AlGaIn)As with 0.635.mu..ltoreq..lambda..ltoreq.0.672.mu., and (AlGaIn)P with 0.56.mu..ltoreq..lambda..ltoreq.0.65.mu..

Third order room temperature nonlinear optical switches

A superlattice comprising alternating layers of undoped GaAs and silicon doped Al.sub.0.3 Ga.sub.0.7 As is used as a magnetoresistor for measuring magnet fields in excess of one Tesla. The magnetic field to be measured is passed vertically through the superlattice and current from a source of constant current is flowed vertically through the resulting superlattice and the voltage drop across the superlattice is measured to provide an indication of the strength of the magnetic field.

Magnetoresistor using a superlattice of GaAs and AlGaAs

A semiconductive device includes a dual channel heterostructure in which a pair of quantum wells separated by a thin barrier layer have their band gaps shifted by applied gate voltages between overlap and non-overlap relationships. When the gaps are in an overlap relationship intraband tunneling through the barrier between the two quantum wells serves to introduce charge carriers in the channels to make them conducting. A specific embodiment uses quantum wells of indium arsenide and gallium antimonide in a host lattice of aluminum antimonide.

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Peter A Wolff