Abstract: A quantum grid infrared photodetector (QGIP) includes a semiconductor substrate with a quantum well infrared photodetector (QWIP) mounted thereon. The QWIP includes a lower contact layer formed on a planar surface of the substrate and a stack of alternate planar barrier layers and planar well layers sandwiched between the lower contact layer and an upper contact layer. The planes of the barrier layers and well layers are substantially parallel to the plane of the planar surface. A plurality of single-slit diffraction units are arranged as a grid in the stack for diffracting incident infrared radiation into a continuum of radiation components directed toward the well layers at different angles with respect to the planes of the well layers. The diffraction units are composed of cavities that extend through the barrier layers, the well layers and the upper contact layer. The cavities have rectangular, square and round shapes and are arranged in rows and columns to form the grid.

Abstract: An acoustic wave imaging system comprises a prism for mounting to the back surface of a piezoelectric substrate of an acoustic wave device. The piezoelectric substrate comprises a front surface on which metallic interdigitated input and output transducers mount for generating acoustic waves on or below the front surface. An electric signal source connects to the input transducer while a load connects to the output transducer. The device may also include spaced metallic reflectors. A large laser beam propagates through an entrance face of the prism, passes through the back surface of the piezoelectric crystal and internally reflects off the front surface of the piezoelectric crystal. The laser beam diffracts into a number of components due to the creation of periodic surface corrugations and or periodic refractive index perturbations beneath the surface, which are caused by the acoustic waves. The beam components exit the prism and are focused by a lens onto its image plane.

Abstract: A hybrid antenna in which the flared end of a parallel plate of a transmion line is coupled to a frequency independent antenna so as to take the place of the higher frequency radiating portion of the antenna.

Abstract: A radiation sensor of the type that acquires a charge or voltage proportil to a dose of radiation. Upon obtaining a predetermined value to the associated voltage proportional to the dose, the voltage is caused to be discharged. A counter keeps track of the number of discharges which is proportional to the total dose of radiation to which the radiation sensor has been exposed. The radiation sensor is thereby prevented from achieving a high charge or voltage which affects the accuracy of the radiation sensor. A calculator and a clock are used to display the value of the dose in any convenient way, such as in relation to tissue dose or average dose rate for a given period of time.

Abstract: A semiconductor infrared detector having a transistor structure with a superlattice base. The superlattice base is between a multiple quantum well (MQW) structure and an electron energy high pass filter. The superlattice base restricts electrons to minibands resulting in no overlap in energy between the energies of the photoelectrons and the dark electrons. As a result, more photoelectrons reach the collector, and the emitter to collector photocurrent transfer ratio is increased. The increased transfer ratio results in increased sensitivity of the detector. The superlattice base between the MQW structure and the electron energy high pass filter comprises multiple alternating wells and barriers. The wells are preferably made of GaAs and the barriers are preferably made of Al.sub.x Ga.sub.1-x As, where x is equal to 0.25.

Abstract: A dual-frequency microstrip antenna has three strips of bare low-dielectric aterial alternating with two strips of copper-clad (one side) high-dielectric material bonded close together on a copper plate having a feed inserted therethrough. A copper-claded layer (one side) low-dielectric material is placed over the five strips and bonded simultaneously. The inner strips separate the region of high-dielectric constant from the region of low-dielectric constant. The microstrip antenna is considered to be a lossy resonating cavity enclosed by a perfect electric conductor and by a perfect magnetic conductor.

Abstract: An electrochemical cell is provided using graphite immersed in molten NaA.sub.4 (mp150.degree. C.) as the cathode, liquid sodium as the anode and .beta. alumina as the sodium ion conducting solid electrolyte to separate the anode and cathode compartments.

Abstract: A thin film of MgIn.sub.2 O.sub.4, is used as an electrode in a ferroelecc device. It provides reasonable conductivity, is inherently transparent and can be grown epitaxially.

Abstract: A quantum wire embedded in another material or a quantum wire which is free standing. Specifically, the quantum wire structure is fabricated such that a quantum well semiconductor material, for example Gallium Arsenide (GaAS), is embedded in a quantum barrier semiconductor material, for example Aluminum Arsenide (AlAs). Preferably, the entire quantum wire structure is engineered to form multiple subbands and is limited to a low dimensional quantum structure. The dimensions of the quantum wire structure are preferably around 150.times.250 .ANG.. This structure has a negative absolute conductance at a predetermined voltage and temperature. As a result of the resonant behavior of the density of states, the rates of electron scattering in the passive region (acoustic phonon and ionized impurity scattering as well as absorption of optical phonons) decrease dramatically as the electron kinetic energy increases.

Abstract: An improved solid state electrochemical cell is provided including a lith ion conducting solid electrolyte. The lithium ion conducting solid electrolyte is a solid solution of lithium germanium oxide and lithium vanadium oxide that includes lithium iodide as an additive. The improved cell can be used as a high temperature high rate rechargeable cell or as a high temperature thermal cell.

Abstract: An optical detector comprised of a MESFET having a larger than usual separation between its source and drain electrodes and a channel between the source and drain electrodes doped with carriers having a density of at least 10.sup.18 /cm.sup.3 whereby variation in the voltage of the gate electrode changes the optical gain.

Abstract: A pyramid shaped etch is made in an n or p type silicon substrate, or any symmetric etch with slanted edges, with p or n type implants in the slanted edges of the etch to form a PN junction. On this structure, an emitter and two collectors are formed by further implanting n+ regions in the PN junction region. To complete the device, ohmic contacts are formed to establish a base region. In operation, an appropriate bias is applied to the emitter through to the base and collectors. By so biasing the device, the device operates as a standard bipolar transistor. The currents of both the minority and majority carriers in the base region will respond to the component of the magnetic field perpendicular to the face of the slanted etch. As a result, there will be a difference in the currents in the collectors. These currents can then be simply calibrated to measure the magnetic field component.

Abstract: The present invention provides for a chemical vapor deposition reactor cher which is fitted with a rotatable and vertically movable susceptor/wafer carrier. The susceptor/wafer carrier, which is a large diameter disk, provides the reactor with the capability of varying the plasma-substrate distance. As those skilled in the art will appreciate, such a susceptor allows high deposition rates to be achieved for a given power level because the flux of the reactant can be increased due to the high speed rotation which will decrease boundary layer thickness during growth. The ability to adjust the source-substrate distance gives more flexibility than fixed dimensional systems. Further, it allows damage in the thin films to be minimized by simple adjustments to the susceptor/wafer carrier. Because the damage to the thin films is minimized, it makes pulsed operation practical and therefore, the films may be grown in an atomic layer epitaxy mode to produce films of high quality and uniformity.

Abstract: To provide a method of measuring thin film thicknesses that is a simple, ck method for determining the thickness of layers as thin as 1-2 nm which, although destructive, consumes very little material.

Abstract: An electrical machine having a stator formed from a pair of cup-shaped permanent magnets symmetrically disposed on opposite sides of a conductive, disk-shaped rotor. The magnets are polarized such that a portion of their external magnetic flux passes in one direction through a short peripheral gap formed by the magnets in which the periphery of the rotor is disposed. The remainder of the external magnetic flux substantially passes in the opposite direction through a cavity defined by the inner volume of the cup-shaped magnets. The inner portion of the disk-shaped rotor is disposed in this cavity. One embodiment of the invention implements the cup-shaped magnets with modified "magic spheres" mounted on either side of the conductive disk-shaped rotor. Other embodiments use a magnetic plate on one side of the disk-shaped rotor to act as a magnetic mirror for a cup-shaped magnet mounted on the other side of the rotor.

Abstract: Uniform films deposited on substrates by laser ablation of targets are inased in size by configuring irradiated target areas as curves rather than flat surfaces. Since material ejected from the target area leaves in a direction normal to the target area, a curved surface results in the material following a trajectory which is at an acute angle to the surface of the substrate being coated. This results in a cone of ejected material which diverges, thus covering an area larger than the irradiated target area. The irradiated target area may be convex, concave or be comprised of a plurality of juxtaposed convex surfaces.

Abstract: Porous silicon is formed by patterning a single crystal silicon substrate prior to electrochemically etching the same. The process is a controlled method of fabricating silicon microstructures which exhibit luminescence and are useful in optoelectronic devices, such as light emitting diodes. The porous silicon produced has a high degree of uniformity and repeatability.

Abstract: The dielectric resonator assembly includes a housing having interior surfaces defining a resonant cavity and a dielectric resonator within the cavity. The dielectric resonator is a ceramic having a high dielectric constant and generates pulses at a desired frequency of oscillation. A pedestal supports the dielectric resonator within the resonant cavity so that it spaces the resonator apart from each of the interior surfaces of the cavity. The assembly also includes a transmission line for transmitting the pulses which pass through at least one of the interior surfaces and has an interior portion spaced apart from the remaining interior surfaces of the cavity. The interior portion of the transmission line is positioned proximate to and in magnetically coupled relationship with the dielectric resonator.

Abstract: An integrated optical intensity modulator. The modulator is an optical waveguide on a semi-insulating substrate and having a core layer for transmitting an optical signal. The modulator includes contiguous the core layer an active cladding which has a multicoupled quantum well structure. The multicoupled quantum well includes at least one pair of quantum wells separated by a barrier. The modulator further includes first and second additional claddings wherein the core layer and the active cladding are interposed between the additional claddings. A voltage source generates an electric field through the active cladding which varies the refractive index of the active cladding as a function of the strength of the electric field for modulating the optical signal.

Abstract: A pair of hollow permanent magnets mounted to form a toroidal stator having cylindrical gaps and opposed cavities. The magnets are polarized such that their magnetic flux passes in one direction through the gaps to intersect the rotor along two cylindrical bands and then passes through the magnetic shell and subsequently in the opposite direction through the cavities to intersect the rotor in a cylindrical region located between the cylindrical bands. An electrical circuit couples a utilization device to the rotor. Another embodiment of the invention uses a magnetic mirror to replace one of the permanent magnets. Still other embodiments teach the use of a plurality of toroidal stators mounted in tandem about a common rotor. The machine may be used as a homopolar generator or a homopolar motor.