Multispectral superconductive quantum detector
AssigneeNorthrop Grumman Corporation
InventorsNathan Bluzer, Martin G. Forrester
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Abstract
An array of superconductive quantum detectors (SQD) with current biased SQUID flowing in one direction from fifty percent of the detectors and flowing in the opposite direction for the other fifty percent. The SQD in one embodiment has a serpentine pattern loop and minimal cross-sectional area to increase kinetic induction. A directly connected SQUID is within the loop of one embodiment and exterior of the loop in another embodiment. Methods of optimizing the signal of the array and different types of Josephson Junctions are also disclosed.
Claims34
An array of superconductive quantum detectors, comprising
- a substrate;
- a plurality of spaced adjacent patterns of superconductive materials deposited on the substrate, each said pattern being endless and having at least one pair of spaced legs, each said pattern being a quantum detector;
- an input and output current biasing node on each pattern between the legs of said at least one pair;
- a read-out superconductive quantum interference device including a pair of spaced Josephson junctions coupled to each pattern;
- conductive material connecting each output node to the input node of an adjacent pattern, a first DC current source connected to the input node of a first pattern;
- and
- a second DC current source having positive and negative terminals, one-half of the negative terminals being connected to one-half of the read-out superconductive quantum interference devices of the array, one-half of the positive terminals being connected to the remaining superconductive quantum interference devices of the array, the remaining positive and negative terminals of the second source being connected to grounds.
A superconductive quantum detector, comprising a substrate;
- an endless thin film strip of superconductive material formed on the substrate in a generally serpentine pattern;
- a pair of spaced current biasing locations positioned to geometrically segregate the serpentine pattern into first and second lengths;
- means shielding the first length from ambient light;
- means exposing the second length to photon radiation, said second length of the endless strip being responsive to the intensity of the photon radiation to change circulating current flowing in the endless pattern, such circulating current representing the change in kinetic inductance produced by de-pairing of Cooper pairs;
- and
- read-out means coupled to the pattern responsive to the circulating current for generating a signal corresponding to the intensity of photon flux striking the exposed length of the superconductive pattern and the length of the endless strip.
A method of optimizing kinetic inductance in a closed loop thin film superconductive endless strip quantum detector of a given size with a given Cooper pair mass, Cooper pair density, and Cooper pair charge, said method comprising
- minimizing the cross sectional area of said thin film superconductive endless strip;
- and
- maximizing the length of the closed loop of the thin film strip within the constraints of the given size.
A superconductive quantum detector, comprising a first substrate and a second substrate overlaying the first substrate;
- an endless thin film strip of superconductive material having a pair of spaced current biasing locations geometrically dividing the endless thin film strip into first and second lengths, the first length of the thin film strip being deposited on the second substrate in the form of a serpentine pattern and exposed to photon radiation, the second length of the thin film strip being sandwiched between the first and second substrate in a serpentine pattern substantially similar to the first length shielding the second length from radiant energy;
- and
- a SQUID coupled to the endless thin film strip for reading out a signal based upon kinetic inductance in the first and second lengths of the endless film strip.
A quantum detector comprising
- a substrate;
- a first endless thin film strip of superconductive material formed on said substrate, the first endless strip having an outer perimetrical boundary portion defined by at least two spaced legs and an additional length of the strip;
- a pair of spaced biasing current nodes on the first strip defining two portions of the first endless strip;
- a second thin film strip of superconductive material having opposite ends connected to the first thin film strip at spaced locations;
- a pair of spaced Josephson junctions formed in the second thin film strip between the connected opposite ends;
- and
- a read-out node on the second thin film strip between the spaced Josephson junctions.
Dependencies are inferred from the claim text.