Abstract: The present invention discloses a photo-detector comprising: an n-type photon absorbing layer of a first energy bandgap; a middle barrier layer, an intermediate layer is a semiconductor structure; and a contact layer of a third energy bandgap, wherein the layer materials are selected such that the first energy bandgap of the photon absorbing layer is narrower than that of said middle barrier layer; wherein the material composition and thickness of said intermediate layer are selected such that the valence band of the intermediate layer lies above the valence band in the barrier layer to create an efficient trapping and transfer of minority carriers from the barrier layer to the contact layer such that a tunnel current through the barrier layer from the contact layer to the photon absorbing layer is less than a dark current in the photo-detector and the dark current from the photon-absorbing layer to said middle barrier layer is essentially diffusion limited and is due to the unimpeded flow of minority carrier

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 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 pixel readout circuit for use with an imaging pixel array, comprising: an input channel for receiving an image signal corresponding to electrical output of a photosensitive element of the pixel; and an electronic circuit interconnected between said input channel and an output readout utility. The electronic circuit comprises a capacitive unit, and a single analyzer. The capacitive unit is controllably linked to input channel for accumulating charge corresponding to received intensity generated by said pixel during a single frame period, and is connected to output readout utility. The signal analyzer unit is controllably linked to input channel and connected to output readout utility, and is configured for analyzing at least a part of said image signal by determining change in amount of accumulated charge corresponding to the received intensity, and upon detecting that the amount of charge satisfies a predetermined condition generating data indicative of a detected event.

Abstract: An infrared (IR) imaging system is presented. The system includes a cooling chamber associated with a cooler generating a certain temperature condition inside the chamber. The cooling chamber has an optical window, and includes thereinside an IR detection unit including one or more detectors thermally coupled to the cooler and at least two cold shields thermally coupled to the cooler and carrying at least two imaging optical assemblies. The at least two imaging optical assemblies are enclosed by the cold shields in between the detection unit and the optical window and thereby define at least two different optical channels for imaging light from the optical window onto the one or more detectors of the detection unit.

Abstract: An infrared (IR) imaging system is presented. The system comprises a cooling chamber associated with a cooler generating a certain temperature condition inside the chamber. The cooling chamber has an optical window, and comprises thereinside an IR detector and a cold shield both thermally coupled to said cooler, and an imaging optical assembly comprising one or more imaging lenses defining a certain fixed focus of the imaging assembly and being enclosed by the cold shield in between the detector and the optical window. The imaging optical assembly and the detector are therefore under the same cooling temperature thereby reducing thermal noise in the detected image.

Abstract: The invention relates to a photo-detector with a reduced G-R noise, which comprises a sequence of a p-type contact layer, a middle barrier layer and an n-type photon absorbing layer, wherein the middle barrier layer has an energy bandgap significantly greater than that of the photon absorbing layer, and there is no layer with a narrower energy bandgap than that in the photon-absorbing layer.

Abstract: A photo-detector with a reduced G-R noise comprises two n-type narrow bandgap layers surrounding a middle barrier layer having an energy bandgap at least equal to the sum of the bandgaps of the two narrow bandgap layers. Under the flat band conditions the conduction band edge of each narrow bandgap layer lies below the conduction band edge of the barrier layer by at least the bandgap energy of the other narrow bandgap layer. When biased with an externally applied voltage, the more negatively biased narrow bandgap layer is the contact layer and the more positively biased narrow bandgap layer is the photon absorbing layer.