Abstract: An optical window for a hypersonic vehicle includes a window substrate and an optical coating on the window substrate, with the coating including multiple alternating layers of different materials. The coating may have many layers, for example having five or more alternating bi-layers and may be configured to still perform its optical function with some of the layers removed, such as by ablation of some of the layers through exposure to hypersonic flow. The different materials of the different layers may have different properties, for example with one of the materials being more resistant to ablation and/or chemical reaction than another of the layers. Coatings for anti-reflection additionally include a region of graded optical index between the sequence of bi-layers and the substrate. The hypersonic vehicle may include an optical sensor which operates by receiving light through the optical window.

Abstract: A method of controlling a temperature profile of an optical window comprising: measuring a temperature-dependent electrical property of a thermally sensitive material included in the optical window using an embedded electromagnetic interference shield in the optical window to determine the temperature profile of the optical window, the embedded electromagnetic interference shield including a two-dimensional array of electrically conductive wires; and based on the measurements, selectively biasing at least one wire of the two-dimensional array of electrically conductive wires to locally alter the temperature-dependent electrical property of the thermally sensitive material in at least one selected spatial region of the optical window to control the temperature profile of the optical window.

Abstract: Methods and apparatus for measuring and optionally adjusting the temperature profile of an optical window. In one example, an optical window with integrated temperature sensing functionality includes a first window layer of an optically transparent material, a second window layer of the optically transparent material, an electromagnetic interference shielding grid disposed between the first and second window layers and including a first electrically conductive structure and a second electrically conductive structure, and a thermally sensitive material disposed between the first and second electrically conductive structures, the thermally sensitive material having an electrical property that varies as a function of temperature.

Abstract: A photoconductor assembly includes a substrate formed of an undoped and single-crystal semiconductor material that is configured to absorb electromagnetic energy, a plurality of electrodes arranged normal to the substrate, and a power supply that applies a voltage to the electrodes for modulating the electromagnetic energy through the substrate.

Abstract: A virtual adhesion method is provided. The virtual adhesion method includes increasing a magnetic characteristic of an initial structure, supporting the initial structure on a surface of a substrate, generating a magnetic field directed such that the initial structure is forced toward the surface of the substrate and forming an encapsulation, which is bound to exposed portions of the surface, around the initial structure.

Abstract: A unitary radome layer assembly is provided and includes a first nanocomposite formulation and a second nanocomposite formulation. The first and second nanocomposite formulations are provided together in a unitary radome layer with respective distribution gradients.

Abstract: A real-time ablation sensor uses an optical detector, such as a spectrometer or radiometer, to detect ablation of a material, for example by detecting a signal indicative of ablation of the material, which may be an engineered material. The optical detector may detect reflected light, either from the material being ablated, or from products of the ablation, such as in the vicinity of the material being ablated. A light source may be used to provide light that is reflected by the material and/or the ablation products, with the reflected light received by the detector. The light may be of a selected wavelength or wavelengths, with the selection made in combination with the selection/configuration of the material to be ablated, and/or the selection/configuration of the optical detector.

Abstract: A dynamic aperture is disclosed. A dynamic aperture includes a base layer, a conductive structure disposed on the base layer, and a layer of a material having a dynamically controllable electrical conductivity that is disposed over the base layer and the conductive structure. A transmission profile of the dynamic aperture is determined by a combination of the conductive structure and the layer of the material. The transmission profile is dynamically alterable by controlling the electrical conductivity of the layer of the material.

Abstract: An optical window for a hypersonic vehicle includes a window substrate and an optical coating on the window substrate, with the coating including multiple alternating layers of different materials. The coating may have many layers, for example having five or more alternating bi-layers and may be configured to still perform its optical function with some of the layers removed, such as by ablation of some of the layers through exposure to hypersonic flow. The different materials of the different layers may have different properties, for example with one of the materials being more resistant to ablation and/or chemical reaction than another of the layers. Coatings for anti-reflection additionally include a region of graded optical index between the sequence of bi-layers and the substrate. The hypersonic vehicle may include an optical sensor which operates by receiving light through the optical window.

Abstract: A real-time ablation sensor uses an optical detector, such as a spectrometer or radiometer, to detect ablation of a material, for example by detecting a signal indicative of ablation of the material, which may be an engineered material. The optical detector may detect reflected light, either from the material being ablated, or from products of the ablation, such as in the vicinity of the material being ablated. A light source may be used to provide light that is reflected by the material and/or the ablation products, with the reflected light received by the detector. The light may be of a selected wavelength or wavelengths, with the selection made in combination with the selection/configuration of the material to be ablated, and/or the selection/configuration of the optical detector.

Abstract: A method includes transmitting first optical energy towards a space being scanned. The method also includes detecting one or more instances of a first material in the space using first return optical energy, where the first return optical energy is based on the transmitted first optical energy. The method further includes, for each of the one or more instances of the first material, transmitting second optical energy towards a portion of the space in which the instance of the first material was detected. The method also includes detecting one or more instances of a second material in the space using second return optical energy, where the second return optical energy is based on the transmitted second optical energy. In addition, the method includes identifying a presence of at least one type of device in the space based on instances of the first and second materials detected in the space.

Abstract: A window installation includes a phase-change filler material sealing an outer edge of the window, and coupling the window to a frame around the window. The filler material in a solid state rigidly holds the window in place. When the filler material is in a liquid state it allows the window to float in its coupling to the frame. There may be supports within the rigid material that contact the window, but allow the window to expand or contract by sliding along the supports. The installation may be useful in situations where the window is subjected to thermal shocks, or other sorts of heating. The installation may be used for a sensor window, and may be part of a hypersonic vehicle.

Abstract: A method includes transmitting first optical energy towards a space being scanned. The method also includes detecting one or more instances of a first material in the space using first return optical energy, where the first return optical energy is based on the transmitted first optical energy. The method further includes, for each of the one or more instances of the first material, transmitting second optical energy towards a portion of the space in which the instance of the first material was detected. The method also includes detecting one or more instances of a second material in the space using second return optical energy, where the second return optical energy is based on the transmitted second optical energy. In addition, the method includes identifying a presence of at least one type of device in the space based on instances of the first and second materials detected in the space.

Abstract: A conduit is placed between a vacuum system and the open air or other gaseous environment. A laser or other excitation source is used to ionize the air on the air-side of the conduit. An axial applied electric field is used to repel positive ions from traversing the tube and reaching the region of the vacuum. Electrons are collected in the vacuum region and disposed of using a Faraday cup. The repelled ions assist in creating a counter pressure to sweep neutral atoms out of the tube and back into the ambient air. As a result, a hollow tube can connect an evacuated volume to the open air without compromising the vacuum. This is a “windowless window.” An array of such tubes can be assembled together to increase the area of the aperture.

Abstract: Methods and apparatus for measuring and optionally adjusting the temperature profile of an optical window. In one example, an optical window with integrated temperature sensing functionality includes a first window layer of an optically transparent material, a second window layer of the optically transparent material, an electromagnetic interference shielding grid disposed between the first and second window layers and including a first electrically conductive structure and a second electrically conductive structure, and a thermally sensitive material disposed between the first and second electrically conductive structures, the thermally sensitive material having an electrical property that varies as a function of temperature.

Abstract: An optical window is provided and includes a core layer, a cladding layer and an electromagnetic interference (EMI) layer interposed between the core and cladding layers.

Abstract: A photoconductor assembly includes a substrate formed of an undoped and single-crystal semiconductor material that is configured to absorb electromagnetic energy, a plurality of electrodes arranged normal to the substrate, and a power supply that applies a voltage to the electrodes for modulating the electromagnetic energy through the substrate.

Abstract: Methods and apparatus for measuring and optionally adjusting the temperature profile of an optical window. In one example, an optical window with integrated temperature sensing functionality includes a first window layer of an optically transparent material, a second window layer of the optically transparent material, an electromagnetic interference shielding grid disposed between the first and second window layers and including a first electrically conductive structure and a second electrically conductive structure, and a thermally sensitive material disposed between the first and second electrically conductive structures, the thermally sensitive material having an electrical property that varies as a function of temperature.

Abstract: A dynamic aperture is disclosed. A dynamic aperture includes a base layer, a conductive structure disposed on the base layer, and a layer of a material having a dynamically controllable electrical conductivity that is disposed over the base layer and the conductive structure. A transmission profile of the dynamic aperture is determined by a combination of the conductive structure and the layer of the material. The transmission profile is dynamically alterable by controlling the electrical conductivity of the layer of the material.

Abstract: Methods and apparatus for measuring and optionally adjusting the temperature profile of an optical window. In one example, an optical window with integrated temperature sensing functionality includes a first window layer of an optically transparent material, a second window layer of the optically transparent material, an electromagnetic interference shielding grid disposed between the first and second window layers and including a first electrically conductive structure and a second electrically conductive structure, and a thermally sensitive material disposed between the first and second electrically conductive structures, the thermally sensitive material having an electrical property that varies as a function of temperature.