Abstract: A dewar assembly is presented for use in an optical IR detection system defining a light collecting region. The dewar assembly comprises a warm shield unit configured as an enclosure for optically enclosing the light collection region and having an optical window through which incident light enters the dewar. The warm shield defines a reflective inner surface configured such that light portions of the incident light propagating through said optical window onto said inner surface are reflected by the inner surface towards regions outside said light collecting region.

Abstract: A device for detecting infrared radiation comprising an array of bolometers for detecting radiation; and in order to read each bolometer, a signal shaping circuitry comprising: a circuitry capable of biasing the bolometer at a predetermined voltage in order to make current flow therethrough; a circuitry capable of generating a common-mode current; and a circuitry capable of integrating the difference between the current that flows through the bolometer and the common-mode current. According to the invention, the device comprises a circuitry capable of injecting current into each bolometer in order to shift its resistance by a predetermined quantity that depends on its offset, current injection being performed prior to readout biasing of the bolometer and the shift being performed according to the direction in which the bolometer's resistance varies as a function of temperature. In addition, correction circuitry is capable of shifting the resistances of bolometers towards a common value.

Abstract: An infrared radiation detector includes: a cryostat having a cold finger ensuring heat exchange with a cold source and a window transparent to infrared radiation to be detected; a mechanically fixed cold plane in heat exchange with the cold finger; a detector unit comprising at least a detector circuit sensitive to the infrared wavelength range to be detected, and in direct or indirect heat exchange with the cold plane; and a mechanically fixed cold shield in heat exchange with the cold plane and limiting stray radiation. The cold shield is rotationally symmetrical. An inside wall of the cold shield has a succession of reliefs distributed in at least one helical pattern. A definition axis of the helical pattern coincides with the axis of revolution of the cold shield.

Abstract: An Infra Red (IR) camera and method of operating the same is disclosed. The camera includes a detector having an infrared focal plane array (IRFPA). The camera is operated in such a fashion, implemented in software, to maximize the detector operating temperature under varying scene temperature and atmospheric conditions in order to achieve a predetermined and adequate level of sensitivity and operability from the detector.

Abstract: In certain embodiments, a system may include a sensor platform, a cold shield, and a support system. The sensor platform supports a sensor system. The cold shield allows first radiation to reach the sensor system and prevents second radiation from reaching the sensor system. The support system is coupled to the cold shield and the platform, and supports the cold shield and maintains a separation between the cold shield and the platform.

Abstract: A heater (15) for a sensor (10) comprises a substrate (20), an electrically conductive heating structure (21) on the substrate (20), and one or more connecting portions (28) for electrically connecting the heating structure (21) to one or more outside terminals (14) of the sensor (10). The substrate (20) is rigid and can comprise ceramics, preferably alumina ceramics.

Abstract: A thermal infrared camera may be used under a wide variety of target-scene radiation conditions, with interchangeable or zoom lenses requiring matching or different size cold stops. A variable aperture assembly of a thermal infrared camera integrates a rigid open truss-like framework that's capped by an aperture ring and bottomed by a driving ring, and a radiation shield, located inside the framework, that contains an aperture ring at an upper side. A plurality of blades that collectively define an aperture positioned between the upper aperture rings. Opposite blade ends are coupled to respective ones of the two aperture rings, permitting pivotal movement in one ring and radial movement in the other ring, when the rings are rotated relative to one another, to change the size of the formed aperture. Both refractive and reflective infrared telescopes may be retro-fitted with variable aperture devices to enhance infrared imaging performance.

Abstract: A radiation sensor device including an integrated circuit chip including a radiation sensor on a surface of the integrated chip, one or more electrical connections configured to connect between an active surface of the integrated circuit chip and a lead frame, a cap attached to said integrated circuit chip spaced from and covering said radiation sensor, the cap having a transparent portion defining a primary lens transparent to the radiation to be sensed, a secondary lens disposed in a recess proximate and spaced from said primary lens transparent to the radiation to be sensed, and an air gap between said primary lens and said secondary lens.

Abstract: A method for maintenance of an array of bolometer-type detectors comprises heating of certain detectors to a threshold temperature. The heating is performed by supplying resistive detection elements with electric currents, and the threshold temperature is determined for each detector as a function of a measurement made previously on said detector. Such method makes it possible to eliminate persistent images caused by radiation overexposure, or by damage to the thermoelectric properties of certain pixels appearing during the manufacture or ageing thereof. The method does not require the use of an oven or Peltier element, thus avoiding the risk for such heating component to damage irreversibly the reading and CMOS addressing circuits on which the detectors are hybridised or deposited.

Abstract: Systems and methods are directed to determining the vacuum integrity within a vacuum package assembly containing an infrared detector, such as within an infrared imaging device. For example for an embodiment, a method of performing a vacuum pressure test on a vacuum package includes changing a first parameter value associated with an infrared detector within the vacuum package to vary a temperature of the infrared detector; measuring a second parameter value associated with the infrared detector based on the changing of the first parameter value; comparing the second parameter value to a threshold value; and determining a vacuum pressure condition of the vacuum package based on the comparing of the second parameter value to the threshold value.

Abstract: The invention relates to a method for controlling the resistance of a bolometer in a bolometer matrix of a sensor, said sensor comprising a circuit for reading said matrix which is capable of addressing said bolometer. According to the invention, the method comprises a step (46) of adjusting the recurrence of addressing the bolometer using the read circuit.

Abstract: An image sensor system includes a detector having a plurality of detector elements and optics having a beam path from an optical element on to the detector. Calibration of the detector can be rapidly effected where the image sensor system has a reference radiating device fixed within the beam path for illuminating the detector elements.

Abstract: A cup assembly for holding a sample to be analyzed spectrochemically, includes a tubular longitudinal member which is disposed symmetrical about a central axis. The tubular member extends longitudinally between a first end and a second end. An indented peripheral flange is defined at the second end. The indented flange has an inverted L shaped cross-section. An annular collar extends longitudinally between a first end and a second end. An internal peripheral flange is defined at the first end. The internal flange has an inverted L shaped cross-section complementing the indented flange of the tubular member. When a substantially thin film is interposed between the second end of the tubular member and the first end of the annular collar, the film is retained between the sample cell body and the collar between the indented flange and the internal flange. The cup may have a funnel shaped sample retaining chamber.

Abstract: A device for the radiometric calibration of infra-red measuring devices is provided. The device is in the form of a heated metal surface that is used as a radiant surface and is coated with a high-emission material. The device includes a spherical segment, the interior of which is coated with the high-emission material and the opening of the spherical segment is used as an aperture for an infra-red device that can be arranged in the center of the aperture.

Abstract: An infrared sensor capable of more highly accurately correcting an electrical signal converted by a light receiving unit is provided. An infrared sensor (100) converts energy of infrared rays radiated from an object (for example, human body) to an electrical signal and outputs the electrical signal, the infrared sensor comprising: a light receiving unit (10) that includes a quantum type infrared detection element (11) and that converts the energy of the infrared rays to an electrical signal; and a correction unit (20) that corrects the output signal from the light receiving unit (10), wherein the light receiving unit (10) and the correction unit (20) are formed of the identical material on the identical substrate (1) and have the identical configuration so that the infrared rays enters in an identical manner.

Abstract: An infrared sensor module includes: an infrared sensor device disposed on a substrate and configured to receive infrared signals; a signal processing circuit device configured to process an output from the infrared sensor device; a metal case which is provided at a predetermined distance from the infrared sensor device, which includes a light incident window provided with an optical system for coupling an image on the infrared sensor device from external infrared signals, and which accommodates the infrared sensor device and the signal processing circuit device; and a sensor cover which is disposed between the infrared sensor device and the case and the signal processing circuit device, and which includes a light-transmitting portion configured to guide the infrared signals entering via the optical system to the infrared sensor device.

Abstract: Implementations of the present disclosure involve an apparatus and method to measure the long-wave irradiance of the atmosphere or long-wave source. The apparatus may involve a thermopile, a concentrator and temperature controller. The incoming long-wave irradiance may be reflected from the concentrator to a thermopile receiver located at the bottom of the concentrator to receive the reflected long-wave irradiance. In addition, the thermopile may be thermally connected to a temperature controller to control the device temperature. Through use of the apparatus, the long-wave irradiance of the atmosphere may be calculated from several measurements provided by the apparatus. In addition, the apparatus may provide an international standard of pyrgeometers' calibration that is traceable back to the International System of Units (SI) rather than to a blackbody atmospheric simulator.

Abstract: An aperture arrangement is disclosed, such as an aperture arrangement suitable for use with a dual wavelength infrared detector. A detector is disclosed which includes a casing; an aperture defined in one end of the casing; and a filter having an inner region and an outer region substantially (e.g., greater than 50%) covering the aperture; wherein the outer region of the filter transmits radiation within a first range of wavelengths and reflects radiation within a second range of wavelengths.

Abstract: A near infrared (NIR) semiconductor laser system is shown for gas sensing. An embodiment is centered on the use of a system with a much wider tunable laser, which today has a scan band of more than 150 nanometers (nm) to as much as 250 nm or more. In some cases the scan band is about 400 nm or more. This is achieved in the current embodiment through the use of a widely tunable microelectromechanical system (MEMS) based Fabry-Perot filter as an integral part of the laser cavity. Using this technology, these systems are capable of capturing a variety of gases in the any of the well-known spectroscopic scan bands, such as the OH, NH or CH. For example, a single laser with a 250 nm scan band window between 1550-1800 nm can capture ten or as many as twenty hydrocarbon-based gases simultaneously.

Abstract: In certain embodiments, a system may include sensor platform, a cold shield, and a support system. The sensor platform supports a sensor system. The cold shield allows first radiation to reach the sensor system and prevents second radiation from reaching the sensor system. The support system is coupled to the cold shield and the platform, and supports the cold shield and maintains a separation between the cold shield and the platform.

Abstract: The present invention is directed to a system and method for advanced chemical sensing utilizing a Terahertz receiver instrument having a compact tunable heterodyne mixer to detect chemical species in a noisy background of pollutants, and provide fast acquisition and analysis of the 0.1-2 THz spectrum. The present invention directly couples a microbolometer with a THz quantum cascade laser (QCL) that is utilized as the local oscillator (LO) source for the receiver.

Abstract: An infrared sensor package includes a housing member, which includes an upper-surface section provided with a transmission member which transmits infrared radiation and a lower-surface section and whose inner space is vacuum-sealed, a plate-like heater member which is disposed within the inner space of the housing member and generates heat, an infrared detection element which is fixed onto the heater member and detects the infrared radiation which is transmitted by the transmission member, and a heat-insulating member which has a low thermal conductivity and a smaller cross-sectional area than that of the heater member, and supports the heater member while being fixed onto the lower-surface section.

Abstract: An infrared radiation detector includes: a cryostat having a cold finger ensuring heat exchange with a cold source and a window transparent to infrared radiation to be detected; a mechanically fixed cold plane in heat exchange with the cold finger; a detector unit comprising at least a detector circuit sensitive to the infrared wavelength range to be detected, and in direct or indirect heat exchange with the cold plane; and a mechanically fixed cold shield in heat exchange with the cold plane and limiting stray radiation. The cold shield is rotationally symmetrical. An inside wall of the cold shield has a succession of reliefs distributed in at least one helical pattern. A definition axis of the helical pattern coincides with the axis of revolution of the cold shield.

Abstract: According to one embodiment of the present invention, a system for viewing an area includes a dewar and an optical system positioned within the dewar. The dewar permits operation of the flux detector at cryogenic temperatures, in some embodiments. The optical system includes an infrared radiation system capable of focusing one or more light beams. The inclusion of the optical system within the cryogenic space of the dewar allows reduction of the overall system length and weight, if desired.

Abstract: A re-imaging optical system includes a front objective lens group, a relay lens and a Dewar assembly. The front objective lens group includes at least three lenses for focusing light entering an entrance pupil and forming a first image located adjacent or near a field stop. The relay lens group includes at least three lenses for focusing light from the first image toward the Dewar assembly. The Dewar assembly includes a cold stop and a cooled detector array for forming a second image. Advantageously, the second image is a magnified version of the first image. Also advantageously, the distance between the entrance pupil and the detector array is less than or equal to 201 millimeters. Furthermore, the lenses of the front objective lens group and the lenses of the relay lens group are made from readily available material, such as silicon and/or germanium.

Abstract: Infrared (IR) temperature measurement and stabilization systems, and methods related thereto are provided. The innovation actively stabilizes temperatures of objects in proximity and within the path between an infrared (IR) sensor and target object. A temperature monitor and controller are employed to regulate power to resistive temperature devices (RTDs) thereby regulating current (and power) to the RTDs. As a result, temperatures of IR visible objects can be actively stabilized for changes, for example, changes in ambient temperatures, resulting in efficient and accurate temperature readings.

Abstract: An Infra Red (IR) camera and method of operating the same is disclosed. The camera includes a detector having an infrared focal plane array (IRFPA). The camera is operated in such a fashion, implemented in software, to maximise the detector operating temperature under varying scene temperature and atmospheric conditions in order to achieve a predetermined and adequate level of sensitivity and operability from the detector.

Abstract: A variable aperture assembly for an infrared camera for use with optics having two or more f-numbers. The variable aperture assembly includes a variable iris disposed substantially along an axis of the infrared camera and is thermally connected to a cooling assembly. The variable iris is capable of causing an infrared radiation admitting opening to vary in size. The infrared radiation admitting openings of the variable aperture assembly can be circular or non-circular, including generally rectangular or racetrack shaped openings. The variable aperture assembly provides f-number matching by adjusting the infrared radiation admitting opening to the size necessary to effectively match the numerous f-numbers of the optics, or by adjusting to a size so that a fixed aperture on the radiation shield becomes the effective aperture stop, providing the f-number matching.

Abstract: The present invention discloses a method and device for measuring dust concentration in flowing gas, particularly atmospheric air. Aerodynamic forces continuously position the intake nozzle (2) along the direction of gas flow. The velocity of the measuring stream in the inlet of the intake nozzle (2) is compared with velocity of gas flowing around the intake nozzle (2) and the possible difference is compensated by changing the velocity of the measuring stream in mechanical way.

Abstract: Electro-thermal feedback is utilized for reducing the effective thermal conductance between the detector stage of a bolometer pixel in a thermal radiation sensor assembly and the environment through its mechanical support structure and electrical interconnects, thereby coming closer to achieving thermal conductance limited primarily through photon radiation. Minimization of the effective thermal conductance associated with the mechanical support structure and electrical interconnects is achieved by electro-thermal feedback that adjusts the temperature of an intermediate stage and the mechanical support structure and electrical interconnects, connecting it to the detector stage, to equal the temperature of the bolometer pixel's detector stage (i.e., by active thermal isolation). Increased temperature sensitivity is preferably achieved through temperature sensing with reverse biased Schottky diodes connected in series.

Abstract: A variable aperture assembly for an infrared camera for use with optics having two or more f-numbers. The variable aperture assembly includes a variable iris disposed substantially along an axis of the infrared camera and is thermally connected to a cooling assembly. The variable iris is capable of causing an infrared radiation admitting opening to vary in size. The infrared radiation admitting openings of the variable aperture assembly can be circular or non-circular, including generally rectangular or racetrack shaped openings. The variable aperture assembly provides f-number matching by adjusting the infrared radiation admitting opening to the size necessary to effectively match the numerous f-numbers of the optics, or by adjusting to a size so that a fixed aperture on the radiation shield becomes the effective aperture stop, providing the f-number matching.

Abstract: An aperture arrangement is disclosed, such as an aperture arrangement suitable for use with a dual wavelength infrared detector. A detector is disclosed which includes a casing; an aperture defined in one end of the casing; and a filter having an inner region and an outer region substantially (e.g., greater than 50%) covering the aperture; wherein the outer region of the filter transmits radiation within a first range of wavelengths and reflects radiation within a second range of wavelengths.

Abstract: A single-photon detector is disclosed that provides reduced afterpulsing without some of the disadvantages for doing so in the prior art. An embodiment of the present invention provides a stimulus pulse to the active area of an avalanche photodetector to stimulate charges that are trapped in energy trap states to detrap. In some embodiments of the present invention, the stimulus pulse is a thermal pulse.

Abstract: A device to detect thermal radiation has a membrane and at least two detector elements that are respectively set up to transduce thermal radiation into an electrical signal and are mounted situated next to one another on the membrane, wherein at least one heat dissipation path is provided on the side of the membrane facing towards the detector elements and/or on the side of the membrane facing away from the detector elements, which heat dissipation path has a higher heat conductivity than the membrane and is connected with the detector elements in a heat-conductive manner via the membrane so that heat can be discharged from the detector elements with the heat dissipation path, whereby the response time of the detector elements is short; and wherein at least one heat barrier that has a lower heat conductivity than the membrane and extends between the detector elements is provided integrated into the membrane, such that a heat conduction in the membrane from the one detector element to the other detector elemen

Abstract: The invention relates to an optronics system equipped with: a detector cooler having a cooling machine, a cryostat, an IR detector placed in the cryostat, and a sensor for measuring the temperature TD of the detector; and a processing card which includes means for servocontrolling the cooling machine according to the temperature TD. The system includes a sensor for sensing the system's internal temperature TS, and the processing card includes means for calculating: the refrigerating time (TMF) based on the temperatures TD and TS, on each “on-off” cycle of the detector cooler, the trend of the drift in the refrigerating time TMF, as a function of the number of “on-off” cycles of the detector cooler, a sudden drift as a function of said trend of the drift of the TMF, and means for storing data used in said calculations; these data are aggregated data and not the measurements of temperatures TD and TS, nor said TMFs, in order to limit the size of the storage means.

Abstract: The invention relates to an optronics system equipped with: a detector cooler having a cooling machine, a cryostat, an IR detector placed in the cryostat, and a sensor for measuring the temperature TD of the detector; and a processing card which includes means for servocontrolling the cooling machine according to the temperature TD.

Abstract: A compact, wide field of view, infrared imaging system with two Mid-Wave Infrared (MWIR) and, optionally, an additional one Long-Wave Infrared (LWIR) band, has a single, color corrected lens element embedded within the detector/dewar assembly. The lens element has two aspherical surface profiles and utilizes a holographic optical element to manipulate and detect bands of energy that are harmonic components of each other. The infrared imaging system simplifies and shrinks the MWIR/LWIR imager while maintaining all of the required functionality. An exemplary infrared imaging apparatus performs at an F-stop (F/#) of at least 1.4 with a square field of view of 90×90 degrees.

Abstract: The present invention provides thermal detectors having an optical cavity that is optimized to couple light into a sensor. Light that is on resonance is coupled with the sensor with as high as 100% efficiency, while light off resonance is substantially reflected away. Light that strikes the sensor from the sides (i.e. not on the optical cavity axis) only interacts minimally with sensor because of the reduced absorption characteristics of the sensor. Narrowband sensors in accordance with the present invention can gain as much as 100% of the signal from one direction and spectral band, while receiving only a fraction of the normal radiation noise, which originates from all spectral bands and directions.

Abstract: A bolometer comprising an outer surface for the thermal absorption of incident radiation in thermal contact with a radiation measurement element having a variable resistance (R) depending on the temperature, the element being in a heat feedback loop comprising a corrector for applying a heating power to a resistive heating means in order to maintain the temperature of the resistor equal to a setpoint temperature (Tref). According to the invention, the resistive heating means comprises the element, the corrector is designed to generate a frequency component (S1) of the heating power, which is applied to a coupling means provided between the element and the corrector in order to apply a DC-free signal to the element, a coupling means, separate from the means, is provided between the element and a DC bias means in order to maintain the resistor at a prescribed continuous operation point.

Abstract: An external optical relay assembly to allow an infrared camera with a fixed aperture to be used with a variety of fore optics, including refractive compound lenses, reflective telescopes, and reflective/refractive lenses, by providing an external, cooled aperture, that can be adjusted to provide effective f-number matching to the fore optic, allowing any f-number fore optic to be used with the infrared camera. This allows users of large families of similar telescopes, for example, to use their inventory of infrared Ritchie-Chrétien telescopes with a single infrared camera, regardless of f-numbers.

Abstract: A focal plan array system of the bolometer type having means for determining the rate of non-uniformity which comprises: (a) an array of i×j pixel detectors of the bolometer type for sensing scenery radiation; (b) a case which accommodates said array of detectors, said case having a front window that provides exposure to the sensing element of all the i×j pixel detectors to radiation coming from the scenery; (c) at least a portion of column j+1 of blind detectors that are shielded from the scenery by a homogeneous reference surface; (d) reading circuitry for reading indication for the scenery radiation as sensed by each of the i×j detectors of the array, and for reading indication for the non uniformity as sensed by said detectors in column (j+1); (e) a register for recording the radiation values as read from all the detectors within column (j+1); and (f) a processing unit for finding the standard deviation ? of all the values in said register, and for comparing the same to a predetermined threshold Q, wherei

Abstract: A focal plan array system of the bolometer type which comprises: (a) an array of i×j pixel detectors of the bolometer type for sensing scenery radiation; (b) a case which accommodates said array of detectors, said case having a front window that provides exposure to the sensing element of all the i×j pixel detectors to radiation coming from the scenery; (c) at least one blind detector of the bolometer type within the case in a column j+1 for sensing case radiation, the sensing elements of said at least one detector are irradiated by one or more reference surfaces whose radiation is proportional to the case radiation; (d) reading circuitry for reading indication for the scenery radiation as sensed by each of the i×j detectors of the array, and for reading indication for the case radiation as sensed by said at least one blind detector; and (e) compensation circuitry for compensating each of said scenery radiation indications of each detector for the effects resulted from the case radiation, based on the case ra

Abstract: A mechanical-optical transducer comprises a readout illumination source providing light having different wavelengths or different polarization states; an image sensor array for sensing the light from the readout illumination source; and a mechanical-optical device including sensing pixels whose optical property change in response to incident thermal infrared radiation, the mechanical-optical device having a reflective surface disposed to selectively reflect light from the readout illumination source to the image sensor array.

Abstract: A flame detector is provided. A circuit board is disposed in a housing. A first light source emits first light. A light guide member comprised of translucent material guides the first light from the first light source to a light emission portion of the light guide member. A first light receiving element detects second light having a predetermined wavelength unique to the flames. A second light source emits third light to a translucent cover which is disposed between an opening of the housing and the first light receiving element. A second light receiving element detects the third light passed through the translucent cover to test the translucency. The first light source, the second light source and the second light receiving element are mounted on the circuit board. The light emission portion is formed into a substantially annular shape which encloses the first light receiving element at a front side of the housing to limit a field of view of the first light receiving element to a predetermined range.

Abstract: A device for detecting infrared radiation including a resistive imaging bolometer, a mechanism for measuring drift in the electrical resistance of the bolometer relative to a reference value of the electrical resistance of the bolometer which corresponds to predetermined operating conditions of the bolometer, and a mechanism for correcting the effects of the drift in resistance or for correcting the drift itself.

Abstract: A thermal radiation sensor is disclosed wherein a semiconductor thermocouple comprised of a pair of silicon diodes is connected in back-to-back relationship, with one of the diodes being located in a detector stage. The other diode is located in a heat bath stage together with a sensed temperature difference amplifier. The detector stage is thermally isolated from the heat bath stage by a low thermal conductivity link that includes electrical wires which connect the back-to-back diodes to the amplifier.

Abstract: An image sensor is provided that includes a focal plane array; a cold shield having a top wall disposed over the focal plane array and defining an aperture operatively configured to be selectively switched between a first diameter and a second diameter that is larger than the first diameter; and a filter element disposed between the cold shield aperture and the focal plane array. The filter element includes a first band-pass filter and a second band-pass filter. The first band-pass filter is disposed directly beneath the cold shield aperture when the cold shield aperture is switched to the first diameter or the second diameter. The second band-pass filter is covered by the top wall of the cold shield when the cold shield aperture is switched to the first diameter and is disposed directly beneath the cold shield aperture when the cold shield aperture is switched to the second diameter.

Abstract: A component for detecting electromagnetic radiation comprises: a housing defining a chamber placed under a vacuum or underpressure, one of the faces of the housing including a window which is transparent to the radiation to be detected and the chamber including at least one detector which is used to detect the radiation in question and is arranged inside said chamber essentially against the transparent window, a getter in order to maintain the vacuum or underpressure in the chamber at an acceptable level, and a thermal stabilization device for ensuring regulation of temperature of the detector(s). The thermal stabilization device consists of a heating resistive element which is integrated into the mass of one of the walls defining the housing.

Abstract: An apparatus and method for imaging incoming radiation. The apparatus includes a radiation shield unit having a cavity. A detector array is positioned at least partially within the cavity and has a planar surface with at least one infrared detector affixed on the detector array. A diffractive optical array is positioned within the cavity and is in thermal communication with the radiation shield unit. The diffractive optical array is configured to diffract and direct the spectral components of the incoming radiation onto the detector array. The apparatus is in an external environment having a predetermined ambient temperature. The radiation shield unit, diffractive optical array and detector array may be temperature-controlled to a temperature that is within a few degrees of the ambient temperature. The radiation shield unit, diffractive optical array and detector array may be temperature-controlled to cryogenic temperatures.

Abstract: A single-photon detector is disclosed that provides reduced afterpulsing without some of the disadvantages for doing so in the prior art. An embodiment of the present invention provides a stimulus pulse to the active area of an avalanche photodetector to stimulate charges that are trapped in energy trap states to detrap. In some embodiments of the present invention, the stimulus pulse is a thermal pulse.