The present invention relates to a plurality of phononic devices and a method of manufacturing thereof. In one embodiment, highly sensitive superconducting cryogenic detectors integrate phononic crystals into their architecture. The phononic structures are designed to reduce the loss of athermal phonons, resulting in lower noise and higher sensitivity detectors. This fabrication process increases the qp generation recombination rate, thus, reducing the noise equivalent power (NEP) without sacrificing the scalability. A plurality of phononic devices, such as a kinetic inductance detector (KID), a transition edge sensor (TES) bolometer, and quarterwave backshort, can be manufactured according to the methods of the present invention.

A system for detecting microwave power. In some embodiments, the system includes: a first resonator including a graphene-insulating-superconducting junction; a probe signal source, coupled to the first resonator; and a probe signal analyzer. The probe signal analyzer is configured: to measure a change in amplitude or phase of a probe signal received by the probe signal analyzer from the probe signal source, and to infer, from the change in amplitude or phase, a change in microwave power received by the graphene-insulating-superconducting junction.

A graphene-based broadband radiation sensor and methods for operation thereof are disclosed. The radiation sensor includes an electrical signal path for carrying electrical signals and one or more resonance structures connected to the electrical signal path. Each resonance structure includes a resonator having a resonant frequency. Each resonance structure also includes a graphene junction connected in series with the resonator, the graphene junction including a graphene layer and having an impedance that is dependent on a temperature of the graphene layer. Each resonance structure further includes a heating element that is thermally coupled to the graphene layer and is configured to receive an incident photon, where the temperature of the graphene layer increases in response to the heating element receiving the incident photon.

An optical device includes a substrate, a dielectric layer on the substrate, a waveguide within the dielectric layer, a light sensitive component (e.g., a photodetector) in the dielectric layer and coupled to the waveguide, and a plurality of light isolation structures in at least one of the substrate or the dielectric layer and configured to prevent stray light from reaching the light sensitive component. In some embodiments, a light isolation structure in the plurality of light isolation structures includes two opposing sidewalls and a filling material between the two opposing sidewalls. The two opposing sidewalls include an optical isolation layer. The filling material is characterized by a coefficient of thermal expansion (CTE) matching a CTE of at least one of the substrate or the dielectric layer.

A superconductor device is manufactured by depositing a barrier layer over a substrate including silicon, the barrier layer including silicon and nitrogen; depositing a seed layer for a superconductor layer over the barrier layer, the seed layer including aluminum and nitrogen; depositing the superconductor layer over the seed layer, the superconductor layer including a layer of a superconductor material, the barrier layer serving as an oxidation barrier between the layer superconductor material and the substrate; and depositing a silicon cap layer over the superconductor layer. In some embodiments, the superconductor device includes a waveguide and a metal contact at a sufficient distance from the waveguide to prevent optical coupling between the metal contact and the waveguide.

An electromagnetic sensor for use in a variety of applications requiring extremely high sensitivity, such as measuring power and characteristics of incident electromagnetic radiation includes a superconducting layer that carries an exchange field for providing a spin splitting effect of charge carriers in the superconducting layer, a metal electrode, and an insulating layer arranged between the superconducting layer and metal electrode to form a spin filter junction therebetween. The electromagnetic sensor provides an antenna including a wave collecting element, in contact with the superconducting layer to convey thereinto external electromagnetic waves that are generated by an external source. An electric measurement device provides an output signal responsive to the amplitude and frequency of the external electromagnetic waves, and contacts the metal electrode to measure an electric current or voltage caused by the spin splitted charge carrier flow from the superconducting layer through the spin filter junction into the metal electrode.

Provided is a superconducting transition-edge thermal sensor, comprising a superconducting film defining an active area for incidence of quanta thereon, wherein the superconducting film is made of a superconductor exhibiting a charge carrier density below 10.sup.13 cm.sup.−2 and an electronic heat capacity below 10.sup.3 kb at the critical temperature Tc of said superconductor, wherein the superconductor is formed by two or more layers of two-dimensional crystals stacked on top of another.

A heat transfer device and method are disclosed. The device includes a working region (i.e., working substance) made from a first superconducting material having a superconducting state and a normal state when magnetized. The first superconducting material has a first energy gap while in the superconducting state. A substrate (i.e., cold reservoir) is connected to the working region at a first tunnel junction. The substrate may be a metallic substrate. A heat sink (i.e., hot reservoir) is connected to the working region at a second tunnel junction. The heat sink is made from a second superconducting material having a second energy gap that is larger than the first energy gap. In a particular example, the heat transfer device includes a metallic substrate is made from Copper, a working region made from Tantalum, a heat sink made from Niobium, and the first and second tunnel junctions are made from Tantalum Oxide.

A superconductor device according to some embodiments comprises a superconductor stack, which includes a superconductor layer and a silicon cap layer over the superconductor layer, the cap layer including amorphous silicon. The superconductor device further comprises a metal contact over a portion of the silicon cap layer and electrically-coupled to the superconductor layer. The metal contact comprises a core including a first metal, and an outer layer around the core that includes a second metal. The portion of the silicon cap layer is converted from silicon to a conductive compound including the second metal to provide low-resistance electrical coupling between the superconductor layer and the metal contact. The superconductor device further comprises a waveguide, and the first portion of the cap layer under the metal contact is at a sufficient lateral distance from the waveguide to prevent optical coupling between the metal contact and the waveguide.

The present invention relates to an integrated reflective backshort fabricated with a phononic-isolated kinetic inductance detector or transition edge sensor. The integrated backshort includes: a silicon wafer; a reflective metal layer bonded to the silicon wafer; a silicon first layer disposed on the reflective metal layer; a structural second layer disposed on the first layer; a first superconductor layer disposed on the second layer as a kinetic inductance detector; and a second superconductor layer disposed on the second layer as leads, a microstrip, a capacitor or filter; wherein a phononic structure is etched in the second layer, leaving holes in the second layer; and wherein the etching penetrates through the holes into the second layer, and stopping on the reflective metal layer, leaving a space under the second layer where edges of the first layer etched under the second layer define a length of the integrated backshort.