Massachusetts Institute of Technology

Theodore M Lyszczarz

Michael W Geis

Jonathan C Twichell

Steven Jay Spector

Joshua Kramer

Mankuan Michael Vai

Matthew E Grein

Nickolay N Efremow

Donna M Lennon

Marc J Burke

Dale C Flanders

Franz Xaver Kaertner

Theodore H Fedynyshyn

Harry R Clark

Fuwan Gan

Sandra J Deneault

Keith E Krohn

Michael F Marchant

Karen M G V Gettings

Kevin E Krohn

Nickolai N Efremow

Yoon Jung

Robert T Schulein

Karen Mgv Gettings

Jung U Yoon

An improved waveguide is disclosed. The waveguide utilizes a luminescent material disposed within or around its perimeter to introduce additional light into the waveguide. For example, the waveguide may include a plurality of planar layers having different refractive indexes. A luminescent material may be disposed along the outer edge of these layers. When light from within the waveguide strikes the luminescent material, it emits light, thereby adding to the light in the waveguide. Not only does the luminescent material introduce more light into the waveguide, it also introduces more light sources, thereby making it more difficult to introduce a probe without blocking at least a portion of the light destined for the image sensor. The luminescent material may be a phosphor.

Phosphor-loaded waveguide

A novel system for generating random numbers is disclosed. The radioactive source emits photons, which causes the release of electrons on the surface of the detector. The detector is configured as a two dimensional array having a plurality of pixels. This release of electrons creates a splatter pattern on the detector, which is then read by the processor. Subsequent photon emissions create a second splatter pattern, which is then read by the processor. The processor compares these two splatter patterns, and generates random numbers based on these two splatter patterns. In certain embodiments, the processor creates a difference matrix which represents a comparison of the two splatter patterns. The processor then classifies each pixel in the difference matrix in accordance with certain rules. In certain embodiments, these classification rules may vary as a function of time or as a function of where on the detector the pixel is disposed.

Random number generator

Method and apparatus for modulation of both the intensity and the polarization of radiation in silicon waveguides by applying a biasing voltage to the waveguide.

Method and apparatus for modulation using a conductive waveguide

A Silicon photodetector contains an insulating substrate having a top surface and a bottom surface. A Silicon layer is located on the top surface of the insulating substrate, where the Silicon layer contains a center region, the center region being larger in thickness than the rest of the Silicon layer. A top Silicon dioxide layer is located on a top surface of the center region. A left wing of the center region and a right wing of the center region are doped. The Silicon photodetector also has an active region located within the center region, where the active region contains a tailored crystal defect-impurity combination and Oxygen atoms.

System and method for providing a high frequency response silicon photodetector

A surface-emission cathode formed on an insulating surface having cantilevered, i.e. 'undercut,' electrodes. Suitable insulating surfaces include negative electron affinity (NEA) insulators such as glass or diamond. The cathode can operate in a comprised vacuum (e.g., 10Torr) with no bias on the electrodes and low vacuum electric fields (e.g., at least 10 V cm). Embodiments of the present invention are inexpensive to fabricate, requiring lithographic resolution of approximately 10 micrometers. These cathodes can be formed over large areas for use in lighting and displays and are suitable for satellite applications, such as cathodes for tethers, thrusters and space-charging neutralizers.

Surface-emission cathodes having cantilevered electrodes

Improved field-emission devices are based on composing the back contact to the emitter material such that electron-injection efficiency into the emitter material is enhanced. Alteration of the emitter material structure near the contact or geometric field enhancement due to contact morphology gives rise to the improved injection efficiency. The devices are able to emit electrons at high current density and lower applied potential differences and temperatures than previously achieved. Wide-bandgap emitter materials without shallow donors benefit from this approach. The emission characteristics of diamond substitutionally doped with nitrogen, having a favorable emitter/vacuum band structure but being limited by the efficiency of electron injection into it, show especial improvement in the context of the invention. The injection-enhancing contacts can be created by combining the emitter material with an appropriate metal compound and annealing or by conventional dry anisotropic etching or ion bombardment techniques.

Field emmitters of wide-bandgap materials

The surface-emission cathodes of the invention are constructed so that the cathode body has a free surface over which electrons are efficiently accelerated after injection from a conductive contact. The junction between the free surface and the contact has the property that the height of the barrier to tunneling from the contact to floating surface states associated with the free surface of the cathode body is lower than both the barrier to emission from the contact to vacuum and the barrier to injection from the contact into the conduction band of the cathode body material. Thus under an applied potential, electrons are injected from the contact into floating surface states associated with the free surface. After acceleration, electrons leave the free surface, either emitted to vacuum or injected into another medium.

Surface-emission cathodes

An energetic-electron emitter providing electrons having kinetic energies on the order of one thousand electron volts without acceleration through vacuum. An average electric field of 10.sup.5 V/m to 10.sup.10 V/m applied across a layer of emissive cathode material accelerates electrons inside the layer. The cathode material is a high-dielectric strength, rigid-structure, wide-bandgap semiconductors, especially type Ib diamond. A light-emitting device incorporates the energetic-electron emitter as a source of excitation to luminescence.

Energetic-electron emitters

Field emitters of wide-bandgap materials and methods for their

A lens or fiberoptic cable focuses energy from a collimated helium neon laser beam upon a point on a mask. Some of the focused energy is reflected from the mask upon a photodetector array in an image plane, and some of this energy is reflected from a substrate closely adjacent to the mask after passing through the mask upon the photodetector array to produce an interference pattern that is sensed and characterized by a spatial frequency representative of the distance between the mask and substrate.

Optical gap measuring

Growing community of inventors

Concord, MA, United States of America

Theodore M Lyszczarz