Abstract: An imager for imaging a plurality of images of a single scene over a plurality of disparate electromagnetic wavelength sets includes front-end optics for outputting a polychromatic, collimated image beam of the scene; a beam displacer configured for splitting the collimated image beam into spatially displaced, mutually parallel beams, and an imaging-sensor array configured for registration of the spatially displaced wavelength sets at disparate locations along the imaging-sensor array. In alternative versions, the beam displacer displaces constituent light beams based on at least one of wavelength and polarization. In various implementations, a back-end focusing element focuses each constituent beam onto a predetermined location along the imaging-sensor array. The imaging-sensor array is optimally configured for simultaneous sampling of the plural images focused thereupon by the back-end focusing elements.

Abstract: An imager for imaging a plurality of images of a single scene over a plurality of disparate electromagnetic wavelength sets includes front-end optics for outputting a polychromatic, collimated image beam of the scene; a beam displacer configured for splitting the collimated image beam into spatially displaced, mutually parallel beams, and an imaging-sensor array configured for registration of the spatially displaced wavelength sets at disparate locations along the imaging-sensor array. In alternative versions, the beam displacer displaces constituent light beams based on at least one of wavelength and polarization. In various implementations, a back-end focusing element focuses each constituent beam onto a predetermined location along the imaging-sensor array. The imaging-sensor array is optimally configured for simultaneous sampling of the plural images focused thereupon by the back-end focusing elements.

Abstract: A method of hydrothermally synthesizing sapphire single crystals doped with trivalent metal ions in a crystal-growth autoclave including a crystal-growth zone and nutrient-dissolution zone in fluid communication with the crystal-growth zone is provided. Implementations of the method including situating within the crystal-growth zone at least one sapphire-based seed crystal and situating within the nutrient-dissolution zone an aluminum-containing material to serve as nutrient. An acidic, trivalent-metal-ion-containing growth solution is introduced into the cavity in a quantity sufficient, at least when heated to a predetermined average temperature, to immerse the at least one seed crystal and the nutrient in the growth solution. The growth solution is selected such that sapphire exhibits retrograde solubility therein and the growth process is carried out while maintaining an interior-cavity pressure within a range between and including each of 3.

Abstract: Apparatus for registering the spectral signature of a dynamic source event include an imaging-sensor array configured to register electromagnetic energy over a predetermined range of electromagnetic wavelengths and an optical system configured for imaging onto the imaging-sensor array a dispersion pattern of electromagnetic energy emitted from a source event external to the optical system. The optical system includes (i) a focusing element and (ii) a selected set of optical dispersion apparatus.

Abstract: A method of classifying an electromagnetic-energy emitting source event as one of a first, second, and third class event includes registering an irradiance spectrum from the source event. The intensity of the energy emitted from the source event is measured within each of first, second and third energy sub-ranges and first, second and third relative-energy values are associated with, respectively, the first, second and third energy sub-ranges. A first class-eliminating determination is rendered by comparing to one another a first selected set of two of the relative-energy values, thereby yielding two remaining-candidate event classes. When necessary, a second class-eliminating determination renders the proper classification for the source event by comparing to one another a second selected set of relative-energy values including the relative-energy value not selected for inclusion in the first selected set of two relative-energy values and one of the previously selected relative-energy values.

Abstract: A multi-image detector assembly for detecting a plurality of correlated images of a single scene over a plurality of disparate electromagnetic wavelength sets includes an imaging-sensor array, a plurality of focusing elements and a plurality of optical filtering elements. The imaging-sensor array has a plurality of detector-array sections, each of which detector-array sections comprises at least two detector-array subsections dedicated to the detection of a common wavelength set associated with that detector-array section. Each focusing element is aligned for focusing upon a corresponding one of the plurality of detector-array sub-sections an image of the scene correlating to the images of the scene focused upon other detector-array sub-sections by the other focusing elements. Additionally, each focusing element and its corresponding detector-array sub-section defines an optical path and each detector-array section has associated with it at least two such optical paths.

Abstract: A detector assembly for imaging a scene over a predetermined temperature range and a predetermined wavelength range including a central wavelength includes an imaging-sensor array, a plurality of focusing elements and a plurality of optical filtering elements. The imaging-sensor array includes a plurality of detector-array sections and the focusing elements are arranged with respect to the detector array such that each focusing element is capable of focusing upon a corresponding one of the detector-array sections an image of the scene correlating to the image of the scene that each of the other focusing elements is capable of focusing upon the detector-array section corresponding thereto. Each focusing element and the detector-array section corresponding thereto defines an associated optical path.

Abstract: A remote sensor for detection of the initiation of combustion includes a broad-band sensor, associated signal processing and an interface to the user. The sensor uses the signature formed by the temporal evolution of the spectral emission intrinsic to combustion as a fingerprint for detecting the combustion. The sensor can autonomously monitor a scene and issue an alert as warranted.

Abstract: A system and method for determining whether the distance between an electromagnetic-energy emitting source and a predetermined location increased, decreased or remained constant between first and second times relies upon the selection of first and second energy bands whose average wavelengths are disparately absorbed as a function of transmission distance. Energy values corresponding to the intensity of detectable energy within each of the first and second sub-ranges at each of the first and second times are assigned.

Abstract: A method of analyzing the spectral signature of a point-like dynamic source event in order to approximate the location of the source event within a predetermined field of view is implemented by a spectral analysis system including (i) a data processing system; (ii) an imaging-sensor array communicatively linked to the data processing system and (iii) an optical system adapted for imaging a dispersion pattern of electromagnetic energy emitted from a source event onto the imaging-sensor array. A dispersion-pattern data set associating the optical system with data indicative of a set of pre-contrived electromagnetic-energy dispersion patterns attributed to the optical system is created based on at least one of (i) theoretically and (ii) experimentally determined characteristics of the optical system and maintained in computer memory.

Abstract: A multi-band direct prism comprising at least first and second prismatic elements of disparate refractive indices facilitates the contemporaneous analysis of dispersed emergent light energy within at least two distinct and predetermined sets of energy wavelengths wherein one wavelength within each of the at least two wavelength sets emerges from the direct vision prism with no net angular deviation.

Abstract: An avalanche photodiode comprises, in various implementations, a p-doped absorption region fabricated from a first material and joined along a hetero-junction with one side of an intrinsic charge-carrier multiplication region fabricated from a second material. Situated on an opposite side of the multiplication region is an n-doped diode cathode. Under reverse bias, the p-doped and n-doped regions assume, respectively, a negative charge and a positive charge and an electric field is present in the multiplication region. The first and second materials are selected to one of (i) minimize and (ii) render non-existent any conduction-band-dependent potential barrier opposing the diffusion of electrons from the absorption region into the multiplication region.

Abstract: An avalanche photodiode charge-carrier multiplication region comprises a first region fabricated from a first material having a first impact ionization threshold and a second region joined to the first region at an interface and fabricated from a second material having a second impact ionization threshold lower than the first impact ionization threshold. The first region includes, in the presence of an applied reverse-bias, first and second oppositely charged layers to establish an elevated, localized electric field within a sub-region of the first region. The first and second charged layers are arranged such that preferred charge carriers are accelerated by the localized electric field just prior to being injected into the second material where they impact ionize at predetermined statistical rate.