Abstract: A high-energy radiation detector is disclosed which uses a semiconductor material to absorb high-energy radiation and emit secondary light in response. The semiconductor is designed to be largely transparent for the interband light it emits so that the generated secondary photons can reach the semiconductor surface, to be detected by a suitable photo-detector. The semiconductor thus plays a role of a scintillator with the emitted light registered by a photo-detector. Two different device embodiments are disclosed. The first embodiment employs a uniform bulk slab of the appropriately chosen semiconductor, such as n-doped InP. Its principal advantage lies in the simplicity and low cost. The second device employs a multi-layer heterostructure. The principal advantage of the second type detector is the possibility of a substantial enhancement in the efficiency of absorption of the primary high-energy radiation.

Abstract: A high-energy radiation detector is disclosed which uses a semiconductor material to absorb high-energy radiation and emit secondary light in response. The semiconductor is designed to be largely transparent for the interband light it emits so that the generated seciondary photons can reach the semiconductor surface, to be detected by a suitable photo-detector. The semiconductor thus plays a role of a scintillator with the emitted light registered by a photo-detector. Two different device embodiments are disclosed. The first embodiment employs a uniform bulk slab of the appropriately chosen semiconductor, such as n-doped InP. Its principal advantage lies in the simplicity and low cost. The second device employs a multi-layer heterostructure. The principal advantage of the second type detector is the possibility of a substantial enhancement in the efficiency of absorption of the primary high-energy radiation.

Abstract: An anisotropically conductive layer ‘ACL’ for mechanical and electrical bonding of two circuit containing structures, such as a flip chip and carrier is disclosed. The ACL is formed of a rigid insulating substrate or membrane with a top and bottom planar surfaces formed with a plurality of pins therein. The pins extend beyond the top and bottom surfaces so that a portion of each pin is exposed. The pins provide electrical connection between contact terminals or pads of the flip chip and carrier and additionally provide mechanical support between the flip chip and carrier so that the flip chip can undergo post-bonding processing without substantial deformation or breaking. A method of electrically and mechanically bonding the flip chip and carrier and a method of making a semiconductor device using the ACL is also disclosed.

Abstract: An anisotropically conductive layer “ACL” (50) for mechanical and electrical bonding of two circuit containing structures, such as a flip chip and carrier is disclosed. The ACL is formed of a rigid insulating substrate (72) or membrane (61) with a top and bottom planar surfaces formed with a plurality of pins therein. The pins extend beyond the top and bottom surfaces so that a portion of each pin is exposed. The pins provide electrical connection between contact terminals or pads of the flip chip and carrier and additionally provide mechanical support between the flip chip and carrier so that the flip chip can under go post-bonding processing without substantial deformation or breaking. A method of electrically and mechanically bonding the flip chip and carrier and a method of making a semiconductor device using the ACL is also disclosed.

Abstract: A semiconductor light source is disclosed comprising a substrate, lower and upper claddings, a waveguide region with imbedded active area, and electrical contacts to provide voltage necessary for the wavelength tuning. The active region includes single or several heterojunction periods sandwiched between charge accumulation layers. Each of the active region periods comprises higher and lower affinity semiconductor layers with type-II band alignment. The charge carrier accumulation in the charge accumulation layers results in electric field build-up and leads to the formation of generally triangular electron and hole potential wells in the higher and lower affinity layers. Nonequillibrium carriers can be created in the active region by means of electrical injection or optical pumping. Radiative recombination occurs between the electrons and holes, accumulated in the ground states of the triangular potential wells formed in the high- and low-affinity layers of each active region periods.

Abstract: In analyzing radiation from a communication link, single-photon counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of optical radiation. Preferred detection techniques include methods in which (i) received optical radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the optical radiation which is intensity-modulated with the preselected code, and (iii) wherein the radiation modulated with a preselected code is received. For registration of the signals received by a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: A quantum dot (QD) laser having greatly reduced temperature sensitivity employs resonant tunnel-injection of carriers into the QDs from a pair of quantum wells (QWs). The carriers are injected through barrier layers. Because the tunnel-injection process is essentially temperature-independent, and because the tunnel-injection of carriers is the dominant source of current through the device, temperature-dependent currents are virtually eliminated, resulting in a device having a temperature-independent threshold current. In an additional device, carriers are injected into QDs from a pair of optical confinement layers (OCLs), either by tunnelling or thermionic emission. Each barrier layer is designed to have a low barrier height for carriers entering the QDs, and a high barrier height for carriers exiting the QDs. As a result, parasitic current from carriers leaving the QDs is greatly reduced, which enables the device to have low temperature sensitivity even without using resonant tunnel-injection and/or QWs.

Abstract: Intersubband semiconductor lasers (ISLs) are of great interest for mid-infrared (2-20 ?m) device applications. These semiconductor devices have a wide range of applications from pollution detection and industrial monitoring to military functions. ISLs have generally encountered several problems which include slow intrawell intersubband relaxation times due to the large momentum transfer and small wave-function overlap of the initial and final electron states in interwell transitions. Overall, the ISL's of the prior art are subject to weak intersubband population inversion. The semiconductor device of the present invention provides optimal intersubband population inversion by providing a double quantum well active region in the semiconductor device. This region allows for small momentum transfer in the intersubband electron-phonon resonance with the substantial wave-function overlap characteristic of the intersubband scattering.

Abstract: Intersubband semiconductor lasers (ISLs) are of great interest for mid-infrared (2-20 &mgr;m) device applications. These semiconductor devices have a wide range of applications from pollution detection and industrial monitoring to military functions. ISLs have generally encountered several problems which include slow intrawell intersubband relaxation times due to the large momentum transfer and small wave-function overlap of the initial and final electron states in interwell transitions. Overall, the ISL's of the prior art are subject to weak intersubband population inversion. The semiconductor device of the present invention provides optimal intersubband population inversion by providing a double quantum well active region in the semiconductor device. This region allows for small momentum transfer in the intersubband electron-phonon resonance with the substantial wave-function overlap characteristic of the intersubband scattering.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: A quantum dot (QD) laser having greatly reduced temperature sensitivity employs resonant tunnel-injection of carriers into the QDs from a pair of quantum wells (QWs). The carriers are injected through barrier layers. Because the tunnel-injection process is essentially temperature-independent, and because the tunnel-injection of carriers is the dominant source of current through the device, temperature-dependent currents are virtually eliminated, resulting in a device having a temperature-independent threshold current. In an additional device, carriers are injected into QDs from a pair of optical confinement layers (OCLs), either by tunnelling or therminonic emission. Each barrier layer is designed to have a low barrier height for carriers entering the QDs, and a high barrier height for carriers exiting the QDs. As a result, parasitic current from carriers leaving the QDs is greatly reduced, which enables the device to have low temperature sensitivity even without using resonant tunnel-injection and/or QWs.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i). fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: An anisotropically conductive layer “ACL” (50) for mechanical and electrical bonding of two circuit containing structures, such as a flip chip and carrier is disclosed. The ACL is formed of a rigid insulating substrate (72) or membrane (61) with a top and bottom planar surfaces formed with a plurality of pins therein. The pins extend beyond the top and bottom surfaces so that a portion of each pin is exposed. The pins provide electrical connection between contact terminals or pads of the flip chip and carrier and additionially provide mechanical support between the flip chip and carrier so that the flip chip can under go post-bonding processing without substantial deformation or breaking. A method of electrically and mechanically bonding the flip chip and carrier and a method of making a semiconductor device using the ACL is also disclosed.

Abstract: A fiber optic sensor for measuring level of fluid consists of an ordered array of multiple optical fibers. Each fiber contains a single sensitive element located on a specific level within the range of fluid level change that transmits different light signals depending on either the sensitive element is immersed in the fluid or located above the level of liquid. The input of the fiber bundle is illuminated by an encoded light beam. A decoding system provides detection of the light patterns at the output and processes it to display the readings. Number of fibers in the bunch determines the number of sensitive sections positioned at different levels and, correspondingly, the accuracy of level measurement.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.

Abstract: In analyzing radiation from a sample, single-quanta counting can be used to advantage especially at low levels of radiation energy, e.g. in the detection of fluorescent radiation. Preferred detection techniques include methods in which (i) fluorescence-stimulating radiation is intensity-modulated in accordance with a preselected code, (ii) wherein it is the fluorescent radiation which is intensity-modulated with the preselected code, and (iii) wherein modulation with a preselected code is applied to a sample to influence a property which functionally affects emitted fluorescent radiation. For registration of the signals from a sensing element of a single-photon detector, time of arrival is recorded, optionally in conjunction with registration of time intervals. Advantageously, in the interest of minimizing the number of pulses missed due to close temporal spacing of pulses, D-triggers can be included in counting circuitry.