A superconducting detection unit, a superconducting detector and a superconducting detection system

Abstract

The application discloses a superconducting detection unit, a superconducting detector and a superconducting detection system, and relates to the technical field of superconducting detection. The superconducting detection unit comprises an inductor, a first capacitor and a substrate. The inductor is used for receiving a to-be-detected optical signal and generating an electrical signal; the first capacitor comprises a first electrode and a second electrode; the substrate is provided with a groove, the surface of the substrate provided with the groove is provided with the second electrode, the second electrode is recessed downward at the groove, the second electrode covers the inner surface of the groove, the second electrode is provided with a dielectric layer, the dielectric layer is covered with the first electrode, the first electrode and the second electrode are connected with the inductor, and the inductor is located on the upper surface of the substrate. Since the first capacitor is arranged in the groove, the area occupied by the first capacitor on the substrate is smaller, the area of a single superconducting detection unit is reduced, more superconducting detection units can be arranged in a superconducting detector array with the same area, the resolution of superconducting detection is improved, and therefore the imaging resolution is improved.

Description

Technical Field

[0001] This application relates to the technical field of photoelectric detection, and more specifically, to a superconducting detection unit, a superconducting detector, and a superconducting detection system. Background Technology

[0002] MKID (Microwave Kinetic Inductance Detectors) superconducting detectors can achieve multiplexed single-photon detection of different parameters, and the measurement signals can be superimposed in the frequency domain. Therefore, the readout circuit only needs to share a single broadband amplifier, greatly simplifying the complexity of the readout circuit. However, existing MKID superconducting detector arrays have low integration density, making it difficult to achieve high-resolution imaging. Summary of the Invention

[0003] This application provides a superconducting detection unit, a superconducting detector, and a superconducting detection system to solve the problem that the existing MKID superconducting detector array has low integration and is difficult to achieve high-resolution imaging.

[0004] In a first aspect, this application provides a superconducting detection unit, comprising: an inductor for receiving a light signal to be detected to generate an electrical signal; a first capacitor including a first electrode and a second electrode; a substrate having a groove on it, the second electrode being disposed on the surface of the substrate with the groove, the second electrode being recessed downward at the groove, the second electrode covering the inner surface of the groove, a dielectric layer being disposed on the second electrode, the first electrode covering the dielectric layer, the first electrode being connected to a first end of the inductor, and the second electrode being connected to a second end of the inductor; the inductor being located in a region on the upper surface of the substrate without a groove.

[0005] In this embodiment, by setting a second electrode on the surface of the substrate with a groove and making the second electrode recessed downward at the groove, and the first electrode covering the dielectric layer set on the second electrode, the first capacitor occupies a smaller area on the substrate compared to the planar capacitor while the capacitance value remains unchanged. This reduces the area of ​​a single superconducting detection unit, and thus allows more superconducting detection units to be arranged in a superconducting detector array of the same area, thereby improving the imaging resolution.

[0006] In one embodiment, the inductor is located above the first capacitor; or, the surface of the first electrode is covered with an insulating layer, and the inductor is disposed on the surface of the insulating layer.

[0007] In this embodiment, by placing the inductor on the surface of the insulating layer or above the first capacitor, the placement of the capacitor does not affect the placement of the inductor, further reducing the area of ​​a single superconducting detection unit.

[0008] In one embodiment, the dielectric layer is recessed downward at the groove, the dielectric layer covers the surface of the second electrode within the groove, and the first electrode is recessed downward at the groove, the first electrode covers the surface of the dielectric layer within the groove.

[0009] In one embodiment, the dielectric layer is recessed downward at the groove, the dielectric layer covers the surface of the second electrode within the groove, and the first electrode fills the groove formed by the downward recess of the dielectric layer.

[0010] In this embodiment, since the dielectric layer is recessed downwards at the groove, the facing area of ​​the first electrode and the second electrode covering the surface of the dielectric layer is larger, so that the area occupied by the first capacitor on the substrate is smaller when the capacitance value remains unchanged.

[0011] In one embodiment, the first capacitor includes at least two grooves.

[0012] In this embodiment, by setting multiple grooves, the areas of the first electrode and the second electrode are larger when the area occupied by the first capacitor on the substrate is the same, thereby making the area occupied by the first capacitor on the substrate smaller when the capacitance value remains unchanged.

[0013] In one embodiment, the first capacitor includes a plurality of sub-capacitors, which are connected in parallel and then connected to the inductor.

[0014] In one embodiment, the first capacitor includes a plurality of first electrodes and / or a plurality of second electrodes, each first electrode being connected to a first end of the inductor and each second electrode being connected to a second end of the inductor.

[0015] In one embodiment, the first capacitor includes a plurality of first electrodes and / or a plurality of second electrodes, wherein the second electrodes, the dielectric layer, and the first electrodes are periodically arranged.

[0016] Secondly, this application provides a superconducting detector, comprising: a first signal line; at least one superconducting detection unit as described above and a plurality of coupling capacitors equal in number to the superconducting detection unit, each superconducting detection unit corresponding to one coupling capacitor; a first end of the inductance of each superconducting detection unit is connected to the first signal line through a corresponding coupling capacitor, a second end of the inductance of each superconducting detection unit is grounded, and the capacitance values ​​of the coupling capacitors corresponding to different superconducting detection units are different.

[0017] In one embodiment, the inductors of each of the superconducting detection units are arranged in an array.

[0018] In this embodiment, since a single superconducting detection unit has a smaller area than the prior art, more superconducting detection units, such as those described in the first aspect embodiment and / or in combination with the first aspect embodiment, can be arranged in a superconducting detector array of the same area, thereby improving the integration of the superconducting detector array and increasing the resolution of the image obtained from the measurement signal obtained by the superconducting detector.

[0019] In one embodiment, the superconducting detector includes at least two of the aforementioned superconducting detection units; the substrate includes at least two, the at least two substrates are stacked, the inductors of the at least two superconducting detection units are disposed on the upper surface of the uppermost substrate, and the first capacitors of the at least two superconducting detection units are respectively located on the at least two substrates, wherein the first capacitor of each superconducting detection unit is located on the same substrate.

[0020] In this embodiment, the height direction is further utilized to reduce the area occupied by the first capacitor and improve the detection resolution.

[0021] In one embodiment, the first signal line and the coupling capacitor are disposed on the side of the substrate of the superconducting detection unit away from the inductor. One end of the coupling capacitor is connected to the first end of the inductor of the superconducting detection unit, and the other end of the coupling capacitor is connected to the first signal line.

[0022] In this embodiment, when the first signal line is connected to the first capacitor of each superconducting detection unit through a coupling capacitor, by setting the coupling capacitor on the side of the substrate away from the inductor, the area required for a single superconducting detection unit in the superconducting detector can be further reduced, thereby further improving the integration of the superconducting detector array.

[0023] Thirdly, this application provides a superconducting detection system, comprising: a power divider, the power divider including a first output terminal and a second output terminal, the power divider being used to receive microwave signals and output the microwave signals through the first output terminal and the second output terminal; a superconducting detector as described above, the first signal line of the superconducting detector being connected to the first output terminal of the power divider, the superconducting detector being used to receive the microwave signals, and when the superconducting detector detects a light signal to be detected, the microwave signals are changed to obtain a measurement signal; a mixer, the input terminal of the mixer being connected to the second output terminal of the power divider and the first signal line of the superconducting detector respectively, the mixer being used to compare the amplitude and phase differences between the microwave signals and the measurement signal, and output a compared analog signal; and an analog-to-digital converter, the analog-to-digital converter being connected to the mixer, the analog-to-digital converter being used to convert the analog signal output by the mixer into a digital signal for output.

[0024] Fourthly, this application provides a multi-photon superconducting detection system, comprising: a superconducting detector as described above, the superconducting detector including multiple superconducting detection units; a beam splitter, the input end of the beam splitter being used to receive the optical signal to be detected, the beam splitter including multiple output ends, the multiple output ends of the beam splitter being configured one-to-one with the inductors of the multiple superconducting detection units, wherein different output ends of the beam splitter correspond to different inductors of the superconducting detection units.

[0025] In this embodiment, the received optical signal is distributed to multiple superconducting detection units by a beam splitter. The multiple superconducting detectors perform single-photon detection on the received optical signal, thereby achieving high resolution of high photon number optical signals and strong light photon detection and counting rate, and improving the detection effect of the superconducting detection system.

[0026] In one embodiment, the device further includes delay devices, with the output of the beam splitter connected one-to-one with the inputs of M delay devices, where M is a positive integer; the superconducting detector includes N superconducting detection units, where N is a positive integer and M>N; N groups of delay devices are configured one-to-one with N superconducting detection units, wherein the output of the delay device is configured corresponding to the inductance of the superconducting detection unit, and the delay time of different delay devices within the group is different.

[0027] In this embodiment, by placing a delay device between the beam splitter and the superconducting detection unit, the count rate of the optical signal arriving at the superconducting detection unit is reduced. This allows the photons contained in the optical signal to be sequentially incident on the same superconducting detection unit within the superconducting detector, achieving high-resolution detection of photon arrival time and photon count. Simultaneously, the beam splitter can distribute the optical signal to multiple superconducting detection units, increasing the maximum photon count rate of the superconducting detection system and further improving its detection performance.

[0028] Fifthly, this application provides a multiphoton superconducting detection system, including a beam splitter, a plurality of delay devices, and a superconducting detector as described in any one of claims 5-6, wherein the superconducting detector includes a superconducting detection unit; the input end of the beam splitter is used to receive the optical signal to be detected, and the output end of the beam splitter is connected to the input ends of the plurality of delay devices in a one-to-one correspondence; the output ends of the delay devices are correspondingly arranged with respect to the inductors of the superconducting detection unit, and the delay times of the plurality of delay devices are different.

[0029] In this embodiment, by setting a delay device between the beam splitter and the superconducting detection unit, the count rate of the optical signal arriving at the superconducting detection unit is reduced, so that the photons contained in the optical signal are successively incident on the same superconducting detection unit in the superconducting detector in a delayed manner, thereby achieving high-resolution detection of photon arrival time and photon number. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a circuit diagram of a superconducting detection unit shown in an embodiment of this application;

[0032] Figure 2 This is a schematic diagram illustrating a structure in which a first capacitor is disposed on a substrate, according to an embodiment of this application.

[0033] Figure 3 This is a schematic diagram illustrating an embodiment of the present application showing an inductor positioned above a first capacitor;

[0034] Figure 4 This is a schematic diagram illustrating another structure in which an inductor is disposed above a first capacitor, as shown in an embodiment of this application.

[0035] Figure 5 This is a schematic diagram illustrating an embodiment of the present application showing an inductor positioned above a first capacitor;

[0036] Figure 6 This is a schematic diagram illustrating another structure in which a first capacitor is disposed on a substrate, according to an embodiment of this application.

[0037] Figure 7 This is a schematic diagram illustrating another structure in which an inductor is disposed above a first capacitor, as shown in an embodiment of this application.

[0038] Figure 8 A schematic diagram of the structure of the first capacitor periodically arranged in this application;

[0039] Figure 9 This is a circuit diagram of a superconducting detector shown in an embodiment of this application;

[0040] Figure 10 This is a schematic diagram showing the connection of the first electrode of the superconducting detection unit to the first signal line via a coupling capacitor, as illustrated in an embodiment of this application.

[0041] Figure 11 This is a schematic diagram illustrating the connection of the second electrode of a superconducting detection unit to a first signal line via a coupling capacitor, as shown in an embodiment of this application.

[0042] Figure 12 This is a schematic diagram showing the connection of the second electrode of another superconducting detection unit to the first signal line via a coupling capacitor, as illustrated in an embodiment of this application.

[0043] Figure 13 This is a structural block diagram of a superconducting detection system shown in an embodiment of this application;

[0044] Figure 14 This is a first embodiment of the multiphoton superconducting detection system shown in the embodiments of this application;

[0045] Figure 15 The second embodiment of the multiphoton superconducting detection system shown in the embodiments of this application;

[0046] Figure 16 The third embodiment of the multiphoton superconducting detection system shown in this application.

[0047] Reference numerals: 10-Superconducting detection system; 100-Superconducting detector; 110-First signal line; 120-Second signal line; 130-Superconducting detection unit; 131-Inductor; 1312-Insulating layer; 132-First capacitor; 1321-First electrode; 1322-Contact; 1323-Dielectric layer; 1324-Second electrode; 133-Substrate; 140-Coupling capacitor; 200-Power divider; 300-Mixer; 400-Beam splitter; 500-Delay device; 20-Multiphoton superconducting detection system. Detailed Implementation

[0048] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0049] In the description of this application, it should be noted that the terms "inner", "outer", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this application is usually placed in. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0050] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0051] The technical solution of this application will now be described in detail with reference to the accompanying drawings.

[0052] Microwave Kinetic Inductance Detectors (MKIDs) are superconducting devices that alter the complex impedance characteristics of a superconductor surface by disrupting Cooper pairs with photon energy when photons are incident on the surface. This impedance change is then converted into frequency and amplitude changes via a resonant circuit, enabling the detection of single photons and photon number resolution. By simultaneously fabricating arrays of superconducting detectors with multiple resonant frequencies, MKIDs can achieve multiplexed single-photon detection with different parameters. Furthermore, the measurement signals can be superimposed in the frequency domain, thus requiring only a single broadband amplifier for the readout circuit, significantly simplifying its complexity. Therefore, MKIDs are easily implemented in array configurations, facilitating imaging-related research.

[0053] However, the current MKID superconducting detector array has low integration and a large center-to-center distance between effective photosensitive units, resulting in low spatial resolution. This makes high-resolution imaging difficult to achieve, or requires the fabrication of larger-scale array units, supplemented by specially designed optical components, to achieve equivalent spatial resolution. Table 1 shows the target surface size of commonly used CCDs (Charge Coupled Devices) and the image resolution at different pixel sizes.

[0054] Table 1

[0055]

[0056] Among them, "MKID array pixel count 1 mm" in Table 1 2 The " / pixel" field indicates that the area of ​​each superconducting detector unit is 1 mm. 2 At that time, the number of pixels in the MKID array. Similarly, "MKID array pixel count 10 μm" 2 The " / pixel" field indicates that the area of ​​each superconducting detector unit is 10 μm. 2 At that time, the number of pixels in the MKID array; "MKID array pixel count 20 um" 2 The " / pixel" field indicates that the area of ​​each superconducting detector unit is 20 μm. 2 At that time, the number of pixels in the MKID array.

[0057] Based on this, this application provides a superconducting detection unit that can effectively improve the integration of superconducting detector arrays and increase spatial resolution.

[0058] Please see Figure 1 This application provides a superconducting detection unit 130, which will be described below in conjunction with... Figure 1 The principle of the superconducting detection unit 130 is explained.

[0059] The superconducting detection unit 130 includes an inductor 131, a first capacitor 132, and a substrate 133 (not shown in the figure).

[0060] In this circuit, inductor 131 operates in a superconducting state and is used to receive the optical signal to be detected in order to generate an electrical signal. In the superconducting state, when photons are incident, their energy disrupts the Cooper pairs, thus altering the complex impedance characteristics of the superconductor surface. This change in impedance is converted into a change in frequency and amplitude through a resonant circuit, enabling the detection of a single photon and photon number resolution. The first capacitor 132, as part of the resonant circuit, is used to extract and resolve the detected signal.

[0061] For easier understanding, please refer to the specific structure of the first capacitor 132. Figure 2 To improve spatial resolution, the first capacitor 132 includes a first electrode 1321 and a second electrode 1324. A groove is formed on a substrate 133, and the second electrode 1324 is disposed on the surface of the groove on the substrate 133. The second electrode 1324 is recessed downwards at the groove and covers the inner surface of the groove. A dielectric layer 1323 is disposed on the second electrode 1324, and the first electrode 1321 is covered on the dielectric layer 1323. The first electrode 1321 is connected to a first end of the inductor 131, and the second electrode 1324 is connected to a second end of the inductor 131. The inductor 131 is disposed on the upper surface of the substrate 133 to receive the light to be measured, i.e., photons or photon beams.

[0062] It should be noted that, in one case, "inductor 131 is located on the upper surface of substrate 133" means the topmost layer of substrate 133, so that the light to be measured can illuminate inductor 131. Inductor 131 can be located in a region of substrate 133 without the first electrode 1321 (or the electrode of the first capacitor). In this case, inductor 131 and the topmost electrode are on the same surface, that is, inductor 131 and the second electrode 1324 are located in different regions of substrate 133. This arrangement makes the structure more compact and simple. In another case, "inductor 131 is located on the upper surface of substrate 133" means that inductor 131 is located above the first electrode 1321. In this case, inductor 131 and the first electrode 1321 are not on the same plane. Inductor 131 can be directly above or diagonally below the first electrode 1321. Preferably, in this case, inductor 131 and the first electrode 1321 are isolated by an insulating layer. This arrangement can further improve the resolution. For easier understanding, please refer to [link to relevant documentation]. Figure 3 and Figure 4 .

[0063] like Figure 3As shown, an insulating layer 1312 is disposed on the first electrode 1321, and a through hole is formed in the insulating layer 1312 to allow the inductor 131 to be connected to the first electrode 1321 and the second electrode 1324 respectively. For example, as shown... Figure 5 As shown, the first electrode 1321 and / or the second electrode 1324 can also be connected to the inductor 131 via the contact 1322.

[0064] When the first electrode 1321 is recessed downwards, as Figure 4 As shown, the insulating layer 1312 fills the groove formed by the first electrode 1321, and the insulating layer 1312 has through holes so that the inductor 131 is connected to the first electrode 1321 and the second electrode 1324 respectively.

[0065] Figure 3 and Figure 4 The positional relationship of the electrodes of the inductor 131 and the first capacitor 132 shown is merely an example for ease of understanding and should not be construed as a limitation of this application.

[0066] Figure 3 and Figure 4 Only the positional relationship of the electrodes of inductor 131 and first capacitor 132 is shown. The specific structure of inductor 131 can be set according to actual needs. For easier understanding, please refer to [link to relevant documentation]. Figure 5 .like Figure 5 As shown, inductor 131 is disposed on insulating layer 1312. In this case, inductor 131 can be embedded within insulating layer 1312 (e.g., Figure 3 , 4 As shown), it can also be disposed on the surface of the insulating layer 1312 (not shown). Due to the through holes opened in the insulating layer 1312, the inductor 131 is connected to the first electrode 1321 and the second electrode 1324 respectively (or the inductor 131 is connected to the first electrode 1321 and the second electrode 1324 respectively through the contact 1322). Figure 5 The inductor setup shown is for ease of understanding only. The specific structure and shape of the inductor can be set according to actual needs. There are no restrictions on the specific structure and shape of the inductor here.

[0067] The first electrode 1321 and the second electrode 1324 are made of conductive materials, such as metal layers like copper or silver. The second electrode 1324 can also be an N+ silicon layer or a P+ silicon layer. The dielectric layer 1323 is an insulating layer, such as a SiO2 layer.

[0068] In one embodiment, to facilitate the connection of the second electrode 1324 to the inductor 131, a contact 1322 is further provided on the substrate 133. This contact 1322 is used to connect the inductor 131 to the first electrode 1321 and / or the second electrode 1324, and the contact 1322 is conductive. For further understanding, please refer to [link to relevant documentation]. Figure 2It is understandable that, besides the method of setting contact 1322 as described here, the second electrode 1324 and the inductor 131 can be connected in other ways. For example, a through hole can be formed in the dielectric layer 1323 covering the second electrode 1324, and the inductor 131 can be connected to the second electrode 1324 through the through hole. No specific connection method is limited here.

[0069] In one embodiment, the dielectric layer 1323 is recessed downward at the groove, and the dielectric layer 1323 covers the surface of the second electrode 1324 within the groove. The first electrode 1321 is recessed downward at the groove, and the first electrode 1321 covers the surface of the dielectric layer 1323 within the groove (see [link]). Figure 2 ) or the groove formed by the downward indentation of the dielectric layer 1323 filled by the first electrode 1321 (see Figure 6 This arrangement allows for a three-dimensional increase in the facing area between the first electrode 1321 and the second electrode 1324 within a limited area, thereby increasing the volume of the first capacitor, improving space utilization, and ultimately enhancing the spatial resolution of the detection unit.

[0070] In one embodiment, the substrate 133 may have only one or multiple recesses. When the first capacitor 132 occupies the same area of ​​the substrate 133, the more recesses there are, the larger the facing area of ​​the first electrode 1321 and the second electrode 1324 of the first capacitor 132, resulting in a larger capacitance value. When multiple recesses are provided on the substrate 133, the specific arrangement of the recesses can be set according to actual needs, such as an array; no specific limitation is made here. The substrate may be a silicon substrate.

[0071] With a fixed area, the deeper the groove, the larger the capacitance of the first capacitor 132; the larger the cross-sectional area of ​​the groove, the smaller the capacitance of the first capacitor 132; the larger the center distance, the smaller the capacitance of the first capacitor 132; the aforementioned center distance refers to the distance between adjacent grooves.

[0072] Take the first capacitor 132, whose groove is a cylindrical hole, as an example.

[0073] When the groove depth is 30µm, the groove diameter is 3µm, the center distance is 3.5µm, and the second electrode 1324 is 30nm, a capacitance value greater than 30nF / mm can be achieved. 2 The capacitance;

[0074] When the groove depth is 30 μm, the groove diameter is 1.5 μm, the center distance is 3.5 μm, and the second electrode 1324 is 30 nm, a capacitance value greater than 60 nF / mm can be achieved. 2 The capacitance;

[0075] When the groove depth is 60 μm, the groove diameter is 1.5 μm, the center distance is 3.5 μm, and the second electrode 1324 is 30 nm, a capacitance value greater than 120 nF / mm can be achieved. 2 The capacitance;

[0076] When the groove depth is 60 μm, the groove diameter is 1.5 μm, the center distance is 3 μm, and the second electrode 1324 is 30 nm, a capacitance value greater than 140 nF / mm can be achieved. 2 The capacitor.

[0077] For example, a three-dimensional first capacitor 132 with a depth of 0-70µm, a groove diameter of 1-3µm, a center-to-center distance of 2-3.5µm, and a dielectric layer of 30nm can achieve >30nF / mm². 2 Capacitor, 1nF / mm² compared to a standard planar capacitor of the same area 2 Increased by more than 30 times. The capacitance calculation formula is C = ε * A / d, where C is the capacitance value and ε is the dielectric constant of the medium, ε = ε₀ε₀. r Where ε0 is the vacuum permittivity, ε r Let A be the relative permittivity of the dielectric layer, A be the area of ​​the capacitor plates facing each other, and d be the distance between the plates. For example, a single first capacitor 132 is arranged in a circular deep-hole array with a diameter of... The depth h = 30 μm, the center distance p = 3.5 μm, the thickness of the insulating dielectric layer d = 30 nm, and the relative permittivity of SiO2 is generally ε. r =3.9-4.5, then the value of capacitor C at this time is approximately , then 1mm 2 The capacitance value is approximately 30nF. If the first capacitor 132 required for a single superconducting detection unit 130 is 10pF, then only a 4*5 array of capacitors is needed, occupying an area of ​​14um*17.5um. At this time, the effective photosensitive area of ​​a single superconducting detection unit 130 is 2um*20um, so the pixel size center-to-center distance of a single superconducting detection unit 130 can be set to 20um.

[0078] The grooves mentioned above can be columnar grooves, such as cylinders, triangular prisms, cuboids, etc., without limitation.

[0079] The bottom of the groove can be a flat surface (e.g.) Figure 7 It can also be a curved surface (such as...) Figure 2 The specific shape of the bottom of the groove is not restricted here.

[0080] In one embodiment, the inductor 131 is disposed above the first capacitor 132, which can be directly above or diagonally above. The inductor 131 can be disposed on the surface of the dielectric layer 1323 that is not completely covered by the first electrode 1321 (or the electrodes of the first capacitor 132 (when multiple electrodes are connected in parallel, the second electrode 1324 may be on top)). Similarly, it can be disposed in the area of ​​the upper surface of the substrate 133 that is not covered by any components. One end of the inductor 131 is connected to the first electrode 1321, and the other end is connected to the second electrode 1324. This arrangement can make full use of the gap to improve spatial resolution.

[0081] In one embodiment, an insulating layer can be covered on the surface of the first electrode 1321, and an inductor 131 can be disposed on the surface of the insulating layer. Similarly, one end of the inductor 131 is connected to the first electrode 1321, and the other end is connected to the second electrode 1324. The number of inductors can be configured on the surface of the insulating layer as needed to meet resolution requirements. This configuration can further reduce the area occupied by the first capacitor 132 on the photon irradiation surface, i.e., increase the capacitance within a given area.

[0082] In one embodiment, the first capacitor 132 may also be composed of multiple sub-capacitors connected in parallel to increase the capacitance.

[0083] In this embodiment, see Figure 8 The first capacitor 132 includes a plurality of first electrodes 1321 and / or a plurality of second electrodes 1324. Each first electrode 1321 is connected to the same end of the inductor 131, and each second electrode 1324 is connected to the end of the inductor 131 that is not connected to the first electrode 1321.

[0084] In this embodiment, the aforementioned plurality of second electrodes 1324, dielectric layer 1323, and first electrode 1321 are periodically arranged to form a multi-layered first capacitor 132. The layers closer to the substrate 133 cover the grooves as much as possible, thereby increasing the capacitance in the height direction and improving space utilization to enhance detection resolution. For example, the first capacitor 132 includes three second electrodes 1324 and two first electrodes 1321. Above the substrate 133, the second electrodes 1324, dielectric layer 1323, first electrode 1321, dielectric layer 1323, second electrode 1324, dielectric layer 1323, first electrode 1321, dielectric layer 1323, and second electrode 1324 are stacked in a periodic arrangement.

[0085] To improve the integration of the superconducting detector 100 and increase the resolution of the image transmitted through it, the superconducting detection unit 130 described above can be used to construct the superconducting detector 100. Please refer to... Figure 9 , Figure 9The circuit diagram of the uniform superconducting detector 100 provided in the embodiments of this application is shown.

[0086] The superconducting detector 100 includes a first signal line 110 and at least one superconducting detection unit 130. The first terminal of the inductor 131 of each superconducting detection unit 130 is connected to the first signal line 110 via a coupling capacitor 140, and the second terminal of the inductor 131 of each superconducting detection unit 130 is grounded. The capacitance values ​​of the coupling capacitors 140 corresponding to different superconducting detection units 130 are different. The coupling capacitors 140 are used to isolate different superconducting detection units 130, preventing their resonant frequencies from interfering with each other. By setting the coupling capacitors 140, mutual interference between different superconducting detection units 130 can be effectively prevented.

[0087] In one embodiment, the inductors 131 of each of the superconducting detection units 130 are arranged in an array.

[0088] In one embodiment, the first signal line 110 and the coupling capacitor 140 are disposed on the side of the substrate 133 of the superconducting detection unit 130 where the inductor 131 is disposed. In this case, the first electrode 1321 of the first capacitor 132 of each superconducting detection unit 130 is connected to the first signal line 110 through the coupling capacitor 140, and the second electrode 1324 is grounded; or, the second electrode 1324 of the first capacitor 132 of each superconducting detection unit 130 is connected to the first signal line 110 through the coupling capacitor 140, and the first electrode 1321 is grounded.

[0089] For easier understanding, please refer to Figure 10 , Figure 11 . Figure 10 This is a schematic diagram showing the first electrode 1321 of the first capacitor 132 of the superconducting detection unit 130 connected to the first signal line 110 via a coupling capacitor 140. Figure 11 This is a schematic diagram showing the second electrode 1324 of the first capacitor 132 of the superconducting detection unit 130 connected to the first signal line 110 via a coupling capacitor 140.

[0090] In another embodiment, the first signal line 110 and the coupling capacitor 140 are disposed on the side of the substrate 133 of the superconducting detection unit 130 away from the inductor 131. One end of the coupling capacitor 140 is connected to the second electrode 1324 of the superconducting detection unit 130, and the other end of the coupling capacitor 140 is connected to the first signal line 110. Specifically, as shown... Figure 12 As shown. Due to... Figure 10 , Figure 11In the illustrated scheme, a transmission line, namely the first signal line 110, needs to be fabricated on the surface of the superconducting detector 100 array to run through the entire detector array. At the same time, the coupling capacitor 140 also needs to occupy a large area. Therefore, in this scheme, the superconducting detector 100 signal transmission line, namely the first signal line 110, the coupling capacitor 140, and the superconducting detector 100 unit are arranged on both sides of the substrate 133. This can reduce the area occupied by the photodetector surface, i.e. the inductor surface, and improve the utilization rate of the photodetector surface, thereby further improving the resolution of the detector.

[0091] Meanwhile, the coupling capacitor 140 can also adopt the same structure as the first capacitor 132 described above.

[0092] Please see Figure 13 This application also provides a superconducting detection system 10, which includes a power divider 200, the aforementioned superconducting detector 100, a mixer 300, and an analog-to-digital converter.

[0093] The power divider 200 includes a first output terminal and a second output terminal. The power divider 200 is used to receive microwave signals and split the microwave signals into two outputs through the first output terminal and the second output terminal.

[0094] The first signal line of the superconducting detector 100 is connected to the first output terminal of the power divider 200 to receive microwave signals. The superconducting detector 100 is used to detect the light signal to be detected, and uses the microwave signal as a carrier to change the microwave signal with the light signal to be detected, thereby obtaining the measurement signal.

[0095] The mixer 300 is connected to the second output terminal of the power divider 200 and the first signal line 110 of the superconducting detector 100, respectively. The mixer 300 is used to compare the amplitude and phase differences between the microwave signal and the measurement signal, and outputs the compared analog signal.

[0096] The analog-to-digital converter is connected to the mixer 300 and is used to convert the analog signal output by the mixer 300 into a digital signal output.

[0097] Please see Figure 14 This application also provides a multi-photon superconducting detection system 20, which includes a beam splitter 400 and a superconducting detector 100. The input end of the beam splitter 400 is used to receive the optical signal to be detected, and the beam splitter 400 includes multiple output ends. The superconducting detector 100 includes multiple superconducting detection units 130. The multiple output ends of the beam splitter 400 are respectively configured to correspond to the inductors 131 of the multiple superconducting detection units 130, so that the photons output from the output ends of the beam splitter 400 can act on the corresponding superconducting detection units for detection. This configuration enables the simultaneous detection of multiple photons.

[0098] In one embodiment, the multiphoton superconducting detection system 20 further includes delay devices 500, and the output terminal of the beam splitter 400 is connected to the input terminals of the M delay devices 500 in a one-to-one correspondence; the superconducting detector 100 includes N superconducting detection units 130; wherein M and N are both positive integers, M>N; the M delay devices 500 are divided into N groups.

[0099] The N groups of delay devices are configured one-to-one with the N superconducting detection units, wherein the output terminal of the delay device is configured to correspond to the inductance of the superconducting detection unit, and the delay time of different delay devices 500 in the group is different.

[0100] For example, such as Figure 15 As shown, M=7, N=4. Therefore, the 7 delay devices 500 are divided into 4 groups, with each group containing 2, 3, 1, and 1 delay devices 500 respectively. Since 7 photons need to be detected, the photons need to be divided into 4 groups using a beam splitter 400, with 2, 3, 1, and 1 photons respectively, for detection by the corresponding superconducting detection unit 130. For a superconducting detection unit 130 with 2 or 3 delay devices 500, the arrival time of each photon needs to be adjusted using the delay devices 500 so that the photons arrive at the superconducting detection unit 130 at different times, thereby performing multi-photon detection in both space and time and improving image resolution.

[0101] Please see Figure 16 In one embodiment, when the superconducting detector 100 in the multiphoton superconducting detection system 20 contains only one superconducting detection unit, a beam splitter 400 and delay devices 500 are required to achieve multiphoton detection. The input terminal of the beam splitter 400 is used to receive the optical signal to be detected, and the output terminal of the beam splitter 400 is connected to the input terminals of multiple delay devices 500 one by one. The output terminals of the delay devices 500 are correspondingly set to the inductors 131 of the superconducting detection unit, and the delay times of the multiple delay devices 500 are different. The beam splitter 400 outputs multiple photons to different output terminals, and after passing through the delay devices 500 with different delay times, the photons arrive at the inductor 131 of the superconducting detection unit 130 at different times, thereby enabling multiphoton detection at different times on the same superconducting detection unit 130.

[0102] The beam splitter mentioned above can be of any model and specification, and can be selected according to actual needs in practical applications. The delay time of the delay device 500 is greater than or equal to the time required for the superconducting detection unit 130 to detect a single photon. The delay device 500 can be a delay line, and the corresponding delay device 500 can be selected according to the actual delay requirements.

[0103] Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A superconducting detection unit, characterized in that, include: An inductor, wherein the inductor is used to receive the optical signal to be detected in order to generate an electrical signal; The first capacitor includes a first electrode and a second electrode; A substrate has a groove on it, a second electrode is disposed on the surface of the substrate with the groove, the second electrode is recessed downward at the groove, the second electrode covers the inner surface of the groove, a dielectric layer is disposed on the second electrode, a first electrode covers the dielectric layer, the first electrode is connected to a first end of an inductor, and the second electrode is connected to a second end of an inductor; the inductor is located on the upper surface of the substrate. The inductor is located above the first capacitor.

2. The superconducting detection unit according to claim 1, characterized in that, The surface of the first electrode is covered with an insulating layer, and the inductor is disposed on the surface of the insulating layer.

3. The superconducting detection unit according to claim 1, characterized in that, The dielectric layer is recessed downwards at the groove, and the dielectric layer covers the surface of the second electrode within the groove. The first electrode is recessed downwards at the groove, and the first electrode covers the surface of the dielectric layer within the groove. or, The dielectric layer is recessed downwards at the groove, and the dielectric layer covers the surface of the second electrode within the groove. The first electrode fills the groove formed by the downward recess of the dielectric layer.

4. The superconducting detection unit according to claim 1, characterized in that, The first capacitor satisfies at least one of the following settings: The first capacitor includes at least two recesses; The first capacitor includes multiple sub-capacitors, which are connected in parallel and then connected to the inductor; The first capacitor includes a plurality of first electrodes and / or a plurality of second electrodes, each first electrode being connected to a first terminal of the inductor, and each second electrode being connected to a second terminal of the inductor; The first capacitor includes a plurality of first electrodes and / or a plurality of second electrodes, wherein the second electrodes, the dielectric layer, and the first electrodes are periodically arranged.

5. A superconducting detector, characterized in that, include: First signal line; At least one superconducting detection unit as described in any one of claims 1-4; Multiple coupling capacitors, the same number as the number of superconducting detection units, with one coupling capacitor corresponding to each superconducting detection unit; The first end of the inductor of each superconducting detection unit is connected to the first signal line through a corresponding coupling capacitor, and the capacitance value of the coupling capacitor is different for different superconducting detection units.

6. The superconducting detector according to claim 5, characterized in that, The inductors of each of the superconducting detection units are arranged in an array.

7. The superconducting detector according to claim 6, characterized in that, The superconducting detector includes at least two superconducting detection units; The substrate includes at least two substrates, and the at least two substrates are stacked together. The inductors of at least two of the superconducting detection units are disposed on the upper surface of the uppermost substrate, and the first capacitors of at least two of the superconducting detection units are respectively located on the at least two substrates, wherein the first capacitor of each of the superconducting detection units is located on the same substrate.

8. The superconducting detector according to claim 6, characterized in that, The first signal line and the coupling capacitor are disposed on the side of the substrate of the superconducting detection unit away from the inductor. One end of the coupling capacitor is connected to the first end of the inductor of the superconducting detection unit, and the other end of the coupling capacitor is connected to the first signal line.

9. A superconducting detection system, characterized in that, include: A power divider, comprising a first output terminal and a second output terminal, is used to receive microwave signals and output the microwave signals through the first output terminal and the second output terminal; the first output terminal serves as a detection signal and the second output terminal serves as a reference signal. The superconducting detector as described in any one of claims 5-8, wherein the first signal line of the superconducting detector is connected to the first output terminal of the power divider, the superconducting detector is used to receive the microwave signal, and when the superconducting detector detects the light signal to be detected, the microwave signal changes to obtain a measurement signal; A mixer, the input of which is connected to the second output of the power divider and the first signal line of the superconducting detector, is used to compare the amplitude and phase differences between the microwave signal and the measurement signal, and output the compared analog signal. An analog-to-digital converter (ADC) is connected to the mixer and is used to convert the analog signal output by the mixer into a digital signal output.

10. A multiphoton superconducting detection system, characterized in that, Includes the superconducting detector as described in any one of claims 5-8, wherein the superconducting detector comprises a plurality of superconducting detection units; A beam splitter has an input terminal for receiving the optical signal to be detected. The beam splitter includes multiple output terminals, each of which is configured to correspond one-to-one with the inductor of a superconducting detection unit. Different output terminals of the beam splitter correspond to different inductors of the superconducting detection units.

11. The multiphoton superconducting detection system according to claim 10, characterized in that, It also includes M delay devices, and the output of the beam splitter is connected one-to-one with the input of the M delay devices, where M is a positive integer; The superconducting detector comprises N superconducting detection units; where N is a positive integer, and M>N; The N groups of delay devices are configured in a one-to-one correspondence with the N superconducting detection units, wherein the output terminal of the delay device is configured in a corresponding manner with the inductance of the superconducting detection unit, and the delay time of different delay devices within the group is different.

12. A multiphoton superconducting detection system, characterized in that, It includes a beam splitter, multiple delay devices, and a superconducting detector as described in any one of claims 5-8, wherein the superconducting detector includes a superconducting detection unit; The input end of the beam splitter is used to receive the optical signal to be detected, and the output end of the beam splitter is connected to the input ends of the multiple delay devices one by one; the output end of the delay device is correspondingly set to the inductor of the superconducting detection unit, and the delay time of the multiple delay devices is different.

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