Abstract: Embodiments described herein relate to an adaptable photonic apparatus including an optical neural network. The photonic apparatus includes an optical input that provides an optical signal. The photonic apparatus also includes a chassis component and an optical neural network (ONN). The chassis component includes at least one modular mounting location for receiving a modular network component. The ONN is operably connected with the optical input and is configured to perform optical processing on the optical signal according to a deep learning algorithm. The ONN includes optical components arranged into layers to form the ONN. The modular network component is an additional optical processing component that is configured to function in cooperation with the ONN to adapt the deep learning algorithm.

Abstract: A device can be configured to cause the superscattering of acoustic waves and/or to enable incident angle-dependent scattering. The acoustic superscattering device can include a body that has an outer peripheral surface. One or more resonators can be defined in the body. The one or more resonators can open to the outer peripheral surface of the body. When there are a plurality of resonators, the resonators are not in communication with each other within the body. The acoustic superscattering device can be configured to cause the superscattering of a target acoustic wave impinging upon the body.

Abstract: Embodiments described herein relate to a photonic apparatus for processing optical signals within an integrated optical pathway. The photonic apparatus a light perception device that perceives light from a surrounding environment of the apparatus. The photonic apparatus also includes an optical neural network (ONN) connected with the light perception device via an optical relay. The optical neural network configured to perform optical processing on the light according to a deep learning algorithm and using optical components.

Abstract: An acoustic impedance matching device can facilitate acoustic transmission across an interface formed by materials having a very large acoustic impedance mismatch (e.g. air-water, or air-elastic polymer). The device can include a first medium. The first medium can have a first acoustic impedance. The device can include a second medium. The second medium can have a second acoustic impedance. The second acoustic impedance can be substantially greater than the first acoustic impedance. Thus, the first acoustic impedance and the second acoustic impedance are substantially mismatched. An interface can be defined between the first medium and the second medium. A bubble can be located in the second medium or the interface. The bubble can act as a resonator and can enable efficient sound transmission despite the large impedance mismatch of the first medium and the second medium.

Abstract: A sound suppression assembly is provided for absorbing acoustic energy from an air circulation device. The assembly includes an air circulation device, such as an axial fan, and a plurality of sparsely-arranged two-sided Helmholtz unit cells disposed in a periodic array. Each unit cell includes a lossy resonator and a lossless resonator. The lossy resonator includes a first chamber portion bounded by at least one first boundary wall defining a first chamber volume, and a first neck forming an opening in the first chamber portion. The lossless resonator includes a second chamber portion bounded by at least one second boundary wall defining a second chamber volume, and a second neck forming an opening in the second chamber portion. The unit cells can be positioned in a circular pattern with the first neck of the lossy resonators directed to a source of acoustic energy from the air circulation device.

Abstract: A thermal management assembly is provided for both removing heat and absorbing acoustic energy. The thermal management assembly includes a heat sink base component and a plurality of thermally conductive fins disposed in a sparsely-arranged array in thermal communication with the heat sink base component. Each fin defines a two-sided Helmholtz unit cell disposed in a periodic array extending from the heat sink base component. Each unit cell includes a lossy resonator and a lossless resonator. The lossy resonator includes a first chamber portion bounded by at least one first boundary wall defining a first chamber volume, and a first neck forming an opening in the first chamber portion. The lossless resonator includes a second chamber portion bounded by at least one second boundary wall defining a second chamber volume, and a second neck forming an opening in the second chamber portion.

Abstract: A broadband sparse acoustic absorber includes a periodic array of spaced apart unit cells, generally having a lateral fill factor less than 0.5. Each unit cell includes a pair of joined, and inverted, Helmholtz resonators, having longitudinal and lateral neck portions that are perpendicular to one another. The longitudinal neck portions are typically covered and/or filled with acoustic absorbing material. Sound suppression systems include sound emitting devices that are at least partially surround by one or more such arrays.

Abstract: One-way sound transmission devices include a planar, acoustically reflective substrate having an aperture that is traversed by an elastic membrane. On one face of the substrate, two resonators are symmetrically spaced apart from the membrane at a first distance, configured to enable constructive interference between the resonators and the membrane. On the opposite face of the substrate, two other resonators are symmetrically spaced apart from the membrane at a second, greater, distance, configured to enable destructive interference between the resonators and the membrane.

Abstract: Sound absorption units for fluid ducts include two acoustically coupled pairs of Helmholtz resonators. The two resonators within each pair have identical resonance frequency, however the upstream resonator within each pair is partly filled with an acoustically lossy porous material, so that the upstream resonator within each pair has greater acoustic loss than its coupled downstream resonator. The upstream pair of resonators has a relatively low resonance frequency, while the downstream pair of resonators has a relatively high resonance frequency. The combination of frequency mismatch between the resonator pairs, and loss mismatch within each resonator pair, produces consistently high sound absorption across a broad frequency spectrum.

Abstract: An invisible sound barrier includes a periodic array of spaced apart, columnar unit cells. Each unit cell includes a pair of joined, and inverted, columnar Helmholtz resonators, having neck portions that point in opposite directions. Each of the Helmholtz resonators can be formed of a sound absorbing material and coated with a light reflective material causing light to reflect around the resonators, thereby conferring invisibility. Each of the Helmholtz resonators can alternatively be formed of a light reflecting material, and positioned in between vertical mirrors, with a transparent material filling space between the resonators and the vertical mirrors.

Abstract: A sparse acoustic absorber includes a periodic array of spaced apart unit cells, generally having a lateral fill factor less than 0.5. Each unit cell includes a pair of joined, and inverted, Helmholtz resonators, having neck portions that point in opposite directions. This structure enables ambient fluid, such as air, to pass through the absorber. The absorber predominantly absorbs acoustic waves having a resonant frequency when such waves are incident on the absorber in one direction, and predominantly reflect such waves when they are incident on the absorber in the opposite direction. Dual-function sound suppression systems incorporate such an absorber into a porous substrate, such as a wire mesh, that enables fluid to pass and alternatively absorbs or reflects sound.

Abstract: Airborne acoustic absorbers include periodic arrays of Helmholtz resonators that are covered and/or partially filled with an acoustically absorptive material, such as a thermoplastic foam. The combined structures have much broader frequency ranges of high acoustic absorption than do structures having only Helmholtz resonators or acoustically absorbing foam.

Abstract: Passively controlled acoustic metamaterials allow transmission of low amplitude acoustic (sound) waves having a resonance frequency and reflect waves having a substantially different frequency. Such materials also reflect waves having the resonance frequency when those waves have an amplitude exceeding a threshold. High amplitude resonance waves cause a resonance membrane contained in unit cells of the metamaterial to contact a rigid structure that is positioned at a longitudinal constraint distance from the resonance membrane in each unit cell. Such contact changes the resonance frequency of the membrane, thereby causing reflection of high amplitude waves. Actively controlled acoustic metamaterials include a ferromagnetic layer on the membrane and an electromagnetic positioned in each unit cell. Activation of the electromagnetic displaces the membrane and thereby shifts the resonance frequency of the membrane, on demand.

Abstract: Double groove diffraction gratings are used in combination with various types of photoelectrodes including dye-sensitized and organic photoelectrodes to increase absorption efficiency as well as to provide one or more of a variety of functions including transparency and reflectivity.

Abstract: Acoustic measurement systems include an enclosure having a high efficiency yet very thin acoustic absorber coating portions thereof, in order to diminish background reflections. The thin acoustic absorber includes a reflective sublayer having a periodic array of indentations on its surface. The periodic array of indentations can be one-dimensional or two dimensional. The thin acoustic absorber further includes a thin absorbing layer overlaid on the reflective sublayer, and typically formed of a viscoelastic foam. The thin acoustic absorber possesses unprecedented absorption efficiency across a broad frequency range and at normal or oblique angles of incidence.

Abstract: A thermal emission structure capable of exhibiting heat release characteristics reverse to those of a Phase-change material used therein includes a first conductor layer, a dielectric layer on the first conductor layer, and a second conductor layer on the dielectric layer and having a periodic geometry, at least one of the first conductor layer and the second conductor layer comprises a Phase-change material having an electrical conduction property that varies between a high-temperature phase and a low-temperature phase.

Abstract: A cloaking device includes cloaking region boundary planes oriented non-planar to each other, each of the cloaking region boundary planes having an outward facing mirror surface and an inward facing opaque surface. The cloaking device includes a cloaking region bounded at least partially by the inward facing opaque surfaces of the cloaking region boundary planes. Half mirrors are spaced apart from and generally parallel to the outward facing mirror surfaces such that a half mirror is spaced apart from and generally parallel to each outward facing mirror surface. Light from an object on an object-side of the cloaking device is directed around an article within the cloaking region and forms an image on an image-side of the cloaking device such the article appears transparent to an observer looking towards the object.

Abstract: A magnetic field shield having a plurality of tunable resonant loops arranged on a planar support medium. The resonant loops are loaded with a lumped component such as a capacitor or variable capacitor and produce magnetic null points. The location of the magnetic null points may be moved three dimensionally about the planar support medium.

Abstract: The first and second media are coupled via evanescent waves generated by surface phonon polaritons thermally excited on surfaces of the first and second media. First and second media made of the same material are disposed with a gap formed between for cutting off thermal conduction and the heat transfer between them is performed via the thermally excited evanescent waves. A third medium is provided on a surface of the first medium on a side toward the second medium. Heat flux flows from the second medium to the first medium in a first state wherein the second medium has a first temperature TH and the first medium has a second temperature TL lower than the TH differ in intensity from heat flux which flows from the first to the second medium in a second state wherein the first medium has the TH and the second medium has the TL.

Abstract: A cloaking device includes cloaking region boundary planes oriented non-planar to each other, each of the cloaking region boundary planes having an outward facing mirror surface and an inward facing opaque surface. The cloaking device includes a cloaking region bounded at least partially by the inward facing opaque surfaces of the cloaking region boundary planes. Half mirrors are spaced apart and generally parallel to the outward facing mirror surfaces such that a half mirror is spaced apart and generally parallel to each outward facing mirror surface. Light from an object on an object-side of the cloaking device is directed around an article within the cloaking region and forms an image on an image-side of the cloaking device such the article appears transparent to an observer looking towards the object.