Abstract: Alloys of GeSbSeTe (GSST) can be used to make actively tunable infrared transmission filters that are small, fast, and solid-state. These filters can be used for hyperspectral imaging, 3D LIDAR, portable bio/chem sensing systems, thermal emission control, and tunable filters. GSST is a low-loss phase-change material that can switch from a low-index (n=3), amorphous state to a high-index (n=4.5), hexagonal state with low loss (k<0.3) over a wavelength range of 2-10 microns or more. The GSST thickness can be selected to provide pure phase modulation, pure amplitude modulation, or coupled phase and amplitude modulation. GSST can be switched thermally in an oven, optically with visible light, or electrically via Joule heating at speeds from kilohertz to Gigahertz. It operates with reversible and polarization independent transmission switching over a wide incident angle (e.g., 0-60 degrees).

Abstract: A seismic wave damping system, and a corresponding method, includes elements, embedded within a host medium, the elements defining a seismic damping structure, and the elements being arranged to form a border of a protection zone. The seismic damping structure is configured to attenuate power of a seismic wave, traveling from a distal medium to the host medium, that is incident at the protection zone. The seismic damping structure is characterized by a resonance frequency. The system further includes an anti-resonance damping structure positioned within the protection zone and configured to dampen a residual wave propagating within the protection zone at the resonance frequency. Embodiment systems offer synergistic advantages because resonance frequencies of seismic wave damping structures may be predicted by calculation and an anti-resonance damping structure may be built to attenuate waves of primarily only specific resonance frequencies supported by the seismic wave damping structure.

Abstract: A seismic wave damping structure can include a structural arrangement including at least one pair of elements, each angled with respect to a vertical and extending into the earth and toward a protection zone. The elements thus form a tapered aperture, the structural arrangement defining the protection zone at an upper portion of the aperture. Each element defines an inner volume and contains a medium resistant to passage of an anticipated seismic wave in earth having a wavelength at least one order of magnitude greater than a cross-sectional dimension of the inner volume of each of the elements. The medium is at least one of air, gas, water, and viscous fluid. The structural arrangement is configured to attenuate power from the anticipated seismic wave within the protection zone relative to power from the anticipated seismic wave external to the protection zone.

Abstract: Alloys of GeSbSeTe (GSST) can be used to make actively tunable infrared transmission filters that are small, fast, and solid-state. These filters can be used for hyperspectral imaging, 3D LIDAR, portable bio/chem sensing systems, thermal emission control, and tunable filters. GSST is a low-loss phase-change material that can switch from a low-index (n=3), amorphous state to a high-index (n=4.5), hexagonal state with low loss (k<0.3) over a wavelength range of 2-10 microns or more. The GSST thickness can be selected to provide pure phase modulation, pure amplitude modulation, or coupled phase and amplitude modulation. GSST can be switched thermally in an oven, optically with visible light, or electrically via Joule heating at speeds from kilohertz to Gigahertz. It operates with reversible and polarization independent transmission switching over a wide incident angle (e.g., 0-60 degrees).

Abstract: An elastic wave damping structure can include a structural arrangement of at least two elements, each with an inner volume and containing a medium resistant to passage of an elastic wave. Example elements can be earth boreholes or water pylons. The structural arrangement can taper from an upper aperture to a lower aperture, the structural arrangement defining a protection zone at the upper aperture. The structural arrangement can be configured to attenuate power from the anticipated elastic wave within the protection zone relative to power from the anticipated elastic wave external to the protection zone. A grouping may include elements that form acute or obtuse angles with a direction of an elastic wave to attenuate wave power. High-value buildings or other structure in a protection zone on land or in water can be substantially shielded from seismic or water waves.

Abstract: A seismic, water, or acoustic wave damping structure can include a structural arrangement of at least two elements, each with an inner volume and containing a medium resistant to passage of an anticipated wave. Example elements can be earth boreholes or water pylons. The structural arrangement can taper from an upper aperture to a lower aperture, the structural arrangement defining a protection zone at the upper aperture. The structural arrangement can be configured to attenuate power from the anticipated wave within the protection zone relative to power from the anticipated wave external to the protection zone. A grouping may include elements that form acute or obtuse angles with a direction of a wave to attenuate wave power. High-value buildings or other structure in a protection zone on land or in water can be substantially shielded from seismic or water waves.

Abstract: An embodiment according to the invention provides an optical filter that combines narrow spectral bandwidth and high rejection of out-of-band radiation with a wide acceptance angle. These filters are based on the nanoscale engineering of materials (“metamaterials”) that possess predefined birefringence determined by a combination of their geometry and material composition. These metamaterials are combined into a functional optical filter that can exhibit true zero crossing, with acceptance angle effectively decoupled from bandwidth, at practically any wavelength of interest.

Abstract: An embodiment according to the invention provides an optical filter that combines narrow spectral bandwidth and high rejection of out-of-band radiation with a wide acceptance angle. These filters are based on the nanoscale engineering of materials (“metamaterials”) that possess predefined birefringence determined by a combination of their geometry and material composition. These metamaterials are combined into a functional optical filter that can exhibit true zero crossing, with acceptance angle effectively decoupled from bandwidth, at practically any wavelength of interest.

Abstract: An elastic wave damping structure can include a structural arrangement of at least two elements, each with an inner volume and containing a medium resistant to passage of an elastic wave. Example elements can be earth boreholes or water pylons. The structural arrangement can taper from an upper aperture to a lower aperture, the structural arrangement defining a protection zone at the upper aperture. The structural arrangement can be configured to attenuate power from the anticipated elastic wave within the protection zone relative to power from the anticipated elastic wave external to the protection zone. A grouping may include elements that form acute or obtuse angles with a direction of an elastic wave to attenuate wave power. High-value buildings or other structure in a protection zone on land or in water can be substantially shielded from seismic or water waves.

Abstract: There is provided an optical limiter device for protecting an object from incident light having a wavelength in the visible, infrared or ultraviolet spectrum. The device comprises a plurality of nanoparticles of a metallic material including free electrons that undergo collective oscillations when exposed to the incident light. The plurality of nanoparticles of the metallic material include a plurality of nanoparticles of a non-spherical particle geometry, which may include a geometry having a plurality of sharp protrusions on a spherical body. The metallic material may include gold, silver, aluminum, indium or copper. The device further comprises a structurally rigid transparent medium in which the plurality of nanoparticles of the metallic material are embedded; and a mechanical support mounting the transparent medium between the incident light and the object.

Abstract: There is provided an optical limiter device for protecting an object from incident light having a wavelength in the visible, infrared or ultraviolet spectrum. The device comprises a plurality of nanoparticles of a metallic material including free electrons that undergo collective oscillations when exposed to the incident light. The plurality of nanoparticles of the metallic material include a plurality of nanoparticles of a non-spherical particle geometry, which may include a geometry having a plurality of sharp protrusions on a spherical body. The metallic material may include gold, silver, aluminum, indium or copper. The device further comprises a structurally rigid transparent medium in which the plurality of nanoparticles of the metallic material are embedded; and a mechanical support mounting the transparent medium between the incident light and the object.

Abstract: A bilayer attenuating phase shift mask for use in photolithography having a phase shift layer and a layer of native oxide-free, elemental metal layer disposed on a substrate. The native oxide-free layer is chosen from platinum, palladium or a metal having like properties. A method of fabrication of the bilayer that uses the same etching ion to perform ion mill etching of the metal layer and chemical etching phase shift layer.

Abstract: A wet chemical process for etching submicron patterned holes in thin metal layers using electrochemical etching with the aid of a wetting agent. In this process, the processed wafer to be etched is immersed in a wetting agent, such as methanol, for a few seconds prior to inserting the processed wafer into an electrochemical etching setup, with the wafer maintained horizontal during transfer to maintain a film of methanol covering the patterned areas. The electrochemical etching setup includes a tube which seals the edges of the wafer preventing loss of the methanol. An electrolyte composed of 4:1 water: sulfuric is poured into the tube and the electrolyte replaces the wetting agent in the patterned holes. A working electrode is attached to a metal layer of the wafer, with reference and counter electrodes inserted in the electrolyte with all electrodes connected to a potentiostat. A single pulse on the counter electrode, such as a 100 ms pulse at +10.