Superconducting microwire single-photon detection device and preparation method thereof

Abstract

According to the superconducting microwire single-photon detection device and the preparation method thereof provided by the invention, the straight groove region and the transition region with certain width and depth are formed by etching the straight line part of the superconducting microwire, and meanwhile, the etching depth of the straight groove region is controlled, so that the critical current of the region is lower than the critical value of the corner region; and a current crowding effect caused by a high duty ratio in a corner region is effectively relieved. The quantum efficiency of the superconducting micron wire can be improved, the structure is simple, the implementation process is convenient and fast, a detector with a large photosensitive area can be easily expanded, and potential application prospects are achieved in the fields of quantum optics, laser ranging, dark matter detection and the like.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a superconducting micron wire single-photon detection device and a preparation method thereof. Background Art

[0002] Superconducting nanowire single-photon detectors (SNSPDs) have excellent properties such as high detection efficiency, low dark counts, low time jitter and high count rate, and are widely used in quantum information, bioluminescence imaging, laser ranging and other fields. In recent years, compared with traditional SNSPDs, the emerging superconducting micrometer-wire single-photon detectors (SMSPDs) have widened the width of superconducting wires from about 100nm to several microns, making the detectors have a larger photosensitive area under the same line length, and can support detection systems with larger field angles. SMSPDs with high photosensitivity show attractive application prospects in the fields of quantum optics, lidar, dark matter detection and deep space optical communications.

[0003] However, achieving high detection sensitivity (quantum efficiency, QE) and high detection efficiency of SMSPD still faces great challenges. First, the detection sensitivity of SMSPD with conventional structure is still very low when detecting photons in the near-infrared band. Secondly, since the line width of SMSPD reaches several microns, when the duty cycle is low (generally less than 0.5), most of the photons will pass directly through the gaps between the superconducting wires without being absorbed, resulting in a significant decrease in the detection efficiency of SMSPD; when the duty cycle is high (generally greater than 0.5), when the current flows through the bend of the zigzag line, it will be concentrated on the inner boundary of the bend, forming the so-called "current crowding effect", which will cause the critical current of the device as a whole to decrease, thereby reducing the sensitivity of the detector. Moreover, when SMSPD is working, the current flowing through the microwire has certain distribution characteristics in the cross-sectional direction, that is, the current density near the edge of the microwire is higher, while the current density in the central area of ​​the microwire is lower, which makes the quantum efficiency of the microwire detecting photons distributed along the cross-sectional direction, and the quantum efficiency in the central area is relatively low.

[0004] In view of this, how to improve the detection sensitivity of SMSPD and solve the "current crowding effect" at the corners has become one of the urgent problems to be solved by technical personnel in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a superconducting micron wire single-photon detection device and a preparation method thereof, which are used to simultaneously solve the problems of the decreased quantum efficiency in the central region of the micron wire of the superconducting micron wire single-photon detector in the prior art, and the "current crowding effect" generated at the corners due to the high duty cycle, thereby improving the detection sensitivity of the superconducting micron wire single-photon detector.

[0006] In order to achieve the above-mentioned object and other related objects, the present invention provides a superconducting micron wire single-photon detection device, wherein the single-photon detection device at least comprises:

[0007] A substrate and a superconducting micron-wire formed on the substrate, wherein the superconducting micron-wire comprises a plurality of straight portions and a curved corner region;

[0008] Among them, the corner area is connected to the adjacent straight part end to end in sequence and the line width of the corner area is not less than the line width of the straight part, a straight groove area and a transition area are formed on the straight part, and the difference between the length of the straight part and the sum of the lengths of the straight groove area and the transition area is at least greater than twice the London penetration depth of the superconducting micron wire.

[0009] Optionally, the plurality of straight line portions are arranged in parallel.

[0010] Optionally, the shape of the transition zone is elliptical, and the ratio of the major axis to the minor axis of the transition zone is 1.5-4.

[0011] Optionally, the width of the straight groove zone is greater than half the width of the straight portion, there is a first distance between the upper edge of the straight groove zone and the corresponding upper edge of the straight portion, there is a second distance between the lower edge of the straight groove zone and the corresponding lower edge of the straight portion, and the first distance and the second distance are both greater than the London penetration depth of the superconducting micron wire.

[0012] Optionally, the straight groove area coincides with a center line of the straight portion, and the first distance and the second distance are equal in size.

[0013] Optionally, the thickness of the straight portion is 3-15 nm, and the depth of the straight groove region is 50%-75% of the thickness of the straight portion.

[0014] The present invention also provides a method for preparing a superconducting micron wire single-photon detection device, the preparation method comprising at least the following steps:

[0015] S1: providing a substrate, and growing a superconducting thin film on the surface of the substrate;

[0016] S2: Spin-coating a photoresist on the superconducting film, and forming the superconducting micron-wire by exposure, development, etching and photoresist removal, wherein the superconducting micron-wire includes a plurality of straight portions and a curved corner region;

[0017] S3: Spin-coating photoresist on the superconducting micrometer wire again, and forming a straight groove area and a transition area on the straight line portion through exposure, development, etching and photoresist removal;

[0018] S4: preparing electrodes on the superconducting microwire.

[0019] Optionally, the thickness of the superconducting film is 3-15 nm, the thickness of the straight portion is 3-15 nm, and the depth of the straight groove region is 50%-75% of the thickness of the straight portion.

[0020] Optionally, the method of forming the superconducting thin film includes direct current magnetron sputtering.

[0021] Optionally, the material of the superconducting thin film includes one of NbN, Nb, NbSi, WSi, TaN, MoSi or NbTiN.

[0022] As described above, the superconducting micron wire single-photon detection device and the preparation method thereof of the present invention have the following beneficial effects: by forming a straight groove zone and a transition zone with a certain width and depth on the straight portion, the quantum efficiency of the central region of the superconducting micron wire is improved; since the cross-sectional area of ​​the straight portion becomes smaller, the critical current of the straight portion is reduced and is less than the critical current of the corner zone, thereby alleviating the "current crowding effect" caused by the high duty cycle in the corner zone, and the elliptical transition zone setting can avoid current accumulation caused by the sharp change in cross-sectional area at the interface between the right angle portion and the corner zone, thereby improving the performance of the single-photon detection device; in addition, the single-photon detection device has the advantages of simple structure and process, and is easier to expand into a detector with a large photosensitive area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic top view of a unit periodic structure of a superconducting micron wire single-photon detector of the present invention.

[0024] Figure 2 Shown is a three-dimensional schematic diagram of a unit periodic structure of a superconducting micron wire single-photon detector of the present invention.

[0025] Figure 3 Shown is a side view schematic diagram of a unit periodic structure of a superconducting micron wire single photon detector of the present invention.

[0026] Figure 4 Shown is a simulation diagram of current distribution in the superconducting microwire in the superconducting microwire single-photon detector of the present invention.

[0027] Figure 5 Shown is a process flow chart of the method for preparing a superconducting micron wire single-photon detector of the present invention.

[0028] Figure 6 It is a schematic diagram showing the structure of the present invention after forming the superconducting micron wire.

[0029] Figure 7 It is a schematic diagram of the structure after forming the straight groove area of ​​the present invention.

[0030] Figure 8 The AFM scanning result of the straight groove region of the superconducting micron wire single photon detector of the present invention is shown.

[0031] Fig. 9 Showing the quantum efficiency of superconducting micron-wire single-photon detectors with and without groove structures for detecting 1550nm photons.

[0032] Component number description

[0033] 10. Substrate; 11. Superconducting film; 12. Superconducting microwire; 121. Straight portion; 122. Corner region; 13. Straight groove region; 14. Transition region; 141. First distance; 142. Second distance; S1 to S4, steps. DETAILED DESCRIPTION

[0034] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0035] See also Figures 1 to 9 . It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings in this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0036] Embodiment 1

[0037] like Figures 1 to 3 As shown, this embodiment provides a superconducting micron wire single photon detection device, and the superconducting micron wire single photon detection device includes:

[0038] A substrate 10 and a superconducting micron-wire 12 formed on the substrate 10, wherein the superconducting micron-wire 12 includes a plurality of straight portions 121 and a bend region 122;

[0039] Among them, the corner area 122 is connected to the adjacent straight part 121 end to end in sequence and the line width of the corner area 122 is not less than the line width of the straight part 121, and a straight groove area 13 and a transition area 14 are formed on the straight part 121, and the sum of the lengths of the straight groove area 13 and the transition area 14 is less than the length of the straight part 121.

[0040] like Figure 3 As shown, the substrate 10 is located at the bottom of the superconducting micron wire single-photon detection device.

[0041] Specifically, the substrate 10 includes but is not limited to a silicon substrate, a DBR substrate or a sapphire substrate. As an example, the substrate 10 is a DBR substrate with high reflectivity. An optical film is coated on the surface of the substrate 10 by a polishing process combined with a thermal oxidation process. The optical film is composed of overlapping SiO2 and Ta2O5 with a certain thickness.

[0042] Specifically, the material of the superconducting micron wire 12 includes but is not limited to NbN, Nb, NbSi, WSi, TaN, MoSi or NbTiN. As an example, the superconducting micron wire 12 is made of NbN. The thickness of the superconducting micron wire 12 is set to 3 to 15 nm, and as an example, it can be 3 nm, 9 nm, and 15 nm, which are not described here one by one.

[0043] Specifically, in this embodiment, the straight portions 121 of the superconducting micron wire 12 are arranged in parallel, each corner region 122 has a 180° fillet to connect two adjacent straight portions 121, and the line width of the corner region 122 is not less than the line width of the straight portion 121. Setting the arc of the corner region 122 to 180° can effectively alleviate the crowding effect of the current in the corner region 122. In actual use, each straight portion 121 can be set to have a certain angle (0° to 180°) as required, which is not limited here.

[0044] Specifically, in this embodiment, the shape of the transition zone 14 is an ellipse, and the ratio of the major axis to the minor axis of the transition zone 14 is 1.5 to 4. The shape of the transition zone 14 is set to be an ellipse, so as to avoid the current gathering caused by the sharp change of the cross-sectional area at the interface between the straight portion 121 and the corner area 122, so as to further alleviate the crowding effect of the current in the corner area 122. The ratio of the major axis to the minor axis of the transition zone 14 is 1.5 to 4, and can be selected as 1.5, 2, 3, and 4 as examples, which are not described one by one here.

[0045] As an example, the width of the straight groove zone 13 is greater than half the width of the straight portion 121, there is a first distance 141 between the upper edge of the straight groove zone 13 and the corresponding upper edge of the straight portion 121, there is a second distance 142 between the lower edge of the straight groove zone 13 and the corresponding lower edge of the straight portion 121, and the first distance 141 and the second distance 142 are both greater than the London penetration depth of the superconducting micron wire 12.

[0046] Specifically, in the present embodiment, a straight groove area 13 and a transition area 14 are formed on the straight portion 121, and the difference between the length of the straight portion 121 and the sum of the lengths of the straight groove area 13 and the transition area 14 is at least greater than twice the London penetration depth of the superconducting micron wire 12, ensuring that the critical currents of the straight groove area 13 and the transition area 14 are sufficiently smaller than the critical current of the corner area 122, avoiding the change in current distribution in the transition area 14 causing the current in the corner area 122 to become more crowded, thereby aggravating the corner crowding effect. The straight groove area 13 serves as a photosensitive area of ​​the single-photon detector, and the width of the straight groove area 13 affects not only the light receiving area of ​​the single-photon detector, but also the distribution of cross-sectional current density and the crowding effect of the current in the corner area 122. The width of the straight groove area 13 is set to be greater than half of the width of the straight portion 121, so that the detector has a higher duty cycle (generally, when the duty cycle value is greater than 0.5, the duty cycle can be considered to be high). As the width of the straight groove area 13 increases, the ratio of the current density in the photosensitive area to the maximum current density of the entire line increases. Figure 4 The current distribution simulation diagram of the superconducting micron wire 12 in the superconducting micron wire 12 single photon detector of this embodiment is shown. Figure 4 It can be seen that when the duty cycle is high and the straight groove area 13 is not formed on the straight portion 121, a "current crowding effect" will be generated in the corner area 122, and the current density in the photosensitive area is much smaller than the current density in the corner area 122, which reduces the performance of the detector. After the straight groove area 13 and the elliptical transition area 14 are formed on the straight portion 121, the cross-sectional area of ​​the straight portion 121 becomes smaller, and the current flux of the straight portion 121 becomes smaller than the current flux of the corner area 122, thereby reducing the critical current of the straight portion 121 and alleviating the "current crowding effect" generated in the corner area 122 due to the high duty cycle. In addition, as the width of the straight groove area 13 increases, the ratio of the current density in the photosensitive area to the maximum current density of the entire line also increases, thereby improving the performance of the detector.

[0047] like Figure 1 and Figure 3As shown, there is a first distance 141 between the upper edge of the straight groove area 13 and the upper edge of the straight portion 121, and there is a second distance 142 between the lower edge of the straight groove area 13 and the lower edge of the straight portion 121. The first distance 141 and the second distance 142 are both greater than the London penetration depth of the superconducting micron wire 12. The London penetration depth is determined by the properties of the selected superconducting material. Through the above arrangement, the distribution of the cross-sectional current density is more concentrated, and the crowding effect of the current in the corner area 122 can be alleviated. As an example, the ratio of the width of the straight groove area 13 to the width of the straight portion 121 is 0.5, 0.6, and 0.8, which are not repeated here.

[0048] Specifically, in this embodiment, the first distance 141 and the second distance 142 are equal in size, that is, the distance between the upper edge of the straight groove area 13 and the upper edge of the straight portion 121 and the distance between the lower edge of the straight groove area 13 and the lower edge of the straight portion 121 are equal, so that the center lines of the straight groove area 13 and the straight portion 121 coincide, which can make the current distribution more uniform.

[0049] Specifically, in this embodiment, the thickness of the straight portion 1211 is 3-15 nm, and as an example, it can be set to 3 nm, 9 nm, and 15 nm, which are not described in detail here. The depth of the straight groove area 13 is 50%-75% of the thickness of the straight portion 121, and as an example, it can be set to 50%, 60%, 70%, and 75%, which are not described in detail here.

[0050] The superconducting micron wire single-photon detection device of the present embodiment improves the quantum efficiency of the central area of ​​the superconducting micron wire 12 by forming a straight groove area 13 and a transition area 14 with a certain width on the straight portion 121; and the straight groove area 13 provided makes the cross-sectional area of ​​the straight portion 121 of the superconducting micron wire 12 smaller, resulting in that the current flux of the straight portion 121 becomes smaller than the current flux of the corner area 122, thereby reducing the critical current of the straight portion 121, so that the critical current of the straight portion 121 is lower than the critical value of the corner area 122, alleviating the "current crowding effect" caused by the high duty cycle in the corner area 122, and setting the transition area 14 to an elliptical shape can avoid current aggregation caused by the sharp change in the cross-sectional area at the interface between the straight portion 121 and the corner area 122, thereby improving the performance of the single-photon detection device; in addition, the single-photon detection device has a simple structure and is easier to expand into a detector with a large photosensitive area.

[0051] Embodiment 2

[0052] like Figure 5 As shown, this embodiment provides a method for preparing a superconducting micron wire single-photon detection device, and the method for preparing a superconducting micron wire single-photon detection device at least includes the following steps:

[0053] S1: providing a substrate 10, and growing a superconducting thin film 11 on the surface of the substrate 10;

[0054] S2: Spin-coating a photoresist on the superconducting film 11, and forming the superconducting micron-wire 12 by exposure, development, etching and photoresist removal. The superconducting micron-wire 12 includes a plurality of straight portions 121 and a curved corner region 122;

[0055] S3: Spin-coating photoresist on the superconducting micron-wire 12 again, and forming a straight groove region 13 and a transition region 14 on the straight portion 121 through exposure, development, etching and photoresist removal;

[0056] S4: preparing electrodes on the superconducting micro-wires 12 .

[0057] As an example, a method of forming the superconducting thin film 11 includes a DC magnetron sputtering method.

[0058] As an example, the material of the superconducting thin film 11 includes one of NbN, Nb, NbSi, WSi, TaN, MoSi or NbTiN.

[0059] Specifically, Figure 6 As shown in a, a substrate 10 is first provided, and a superconducting film 11 for preparing a superconducting micron wire 12 is grown on the surface of the substrate 10 by using a high vacuum magnetron sputtering device. The material of the superconducting film 11 is NbN, and the thickness is set to 3 to 15 nm. In this embodiment, the power of the magnetron sputtering device is turned on to evacuate the vacuum, and argon gas is introduced as a working gas, so that the argon gas in the vacuum chamber is maintained at 2×10 -5 Pa, nitrogen gas is introduced as reaction gas, the mass flow controller is adjusted so that the partial pressure ratio of Ar:N2 is 30:4, the substrate 10 is moved to just below the Nb target, the magnetron sputtering DC power supply of the Nb target is turned on, the current parameter is adjusted to 2.19 A, the sputtering rate is set to 0.8 nm / s, the thickness of the superconducting film 11 is determined by the sputtering rate and the sputtering time, and finally a NbN superconducting film 11 with a thickness of about 12 nm is grown on the substrate 10.

[0060] In this embodiment, the method further includes spin coating photoresist on the surface of the superconducting film 11, the model of the photoresist is AZ703, the spin coating speed is set to 3500rad / min, and the pattern of the superconducting micrometer line 12 is lithographically formed by laser direct writing. The cross used for overlay alignment is first lithographically formed by laser direct writing. After development, Ti-Au material is deposited, and the T-Au film other than the cross is peeled off. Specifically, the substrate 10 with the superconducting film 11 grown on the surface is placed in a thermal evaporation coating machine, and Ti with a thickness of 5nm and Au with a thickness of 50nm are grown. Then, the substrate 10 with the superconducting film 11 grown on the surface is immersed in an N-methylpyrrolidone solution, and placed on a baking table and heated to 100°C for 1 hour. The gold film on the surface is gently blown off with a dropper, and then immersed in acetone and isopropanol solutions and ultrasonicated for 5 minutes, and finally a gold cross mark is left.

[0061] like Figure 6 As shown in FIG. 2 , in this embodiment, after forming the gold cross mark, the surface of the substrate 10 is again spin-coated with photoresist, and the gold cross mark is identified by laser direct writing, and then exposed and developed, and then reactive ion etching is performed to form the superconducting micron wire 12. Specifically, the aforementioned substrate 10 is placed in an etcher and evacuated, and the etching parameters are set after meeting the vacuum conditions. The specific settings of the etching parameters are as follows: CF4 is selected as the gas, the flow rate is set to 30sccm, the etching power is selected to 50mW, the etching time is 39s, and the etching rate is 0.987nm / s.

[0062] As an example, the thickness of the straight portion 121 is 3-15 nm, and the depth of the straight groove region 13 is 50%-75% of the thickness of the straight portion 121 .

[0063] like Figure 7As shown, in this embodiment, after etching to form the superconducting micron wire 12, the photoresist is spin-coated again, and exposure and development are performed after the gold cross mark is identified by laser direct writing, and then reactive ion etching is performed to form the straight groove area 13 and the transition area 14. Since the thickness of the superconducting film 11 is 3 to 15 nm, the thickness of the formed superconducting micron wire 12 is also 3 to 15 nm. Specifically, since the thickness of the oxide layer on the surface of the substrate 10 will affect the depth of the groove formed by etching, before the reactive ion etching is performed to form the straight groove area 13 and the transition area 14, it is necessary to calibrate the etching depth with a test piece. At the same time, in order to make the current distribution more uniform, during etching, it is ensured that the formed straight groove area 13 and the center line of the superconducting micron wire 12 coincide, that is, the distance between the upper edge of the straight groove area 13 and the upper edge of the straight portion 121 and the distance between the lower edge of the straight groove area 13 and the lower edge of the straight portion 121 are equal, and the depth of the straight groove area 13 finally formed is 50%-75% of the thickness of the straight portion 121. The specific settings of etching parameters are as follows: CF4 is selected as gas, the flow rate is set to 30sccm, the etching power is selected to 40mW, the etching time is 18-22s, and the etching rate is 0.79nm / s. Figure 8 As shown, it is an AFM scanning result diagram of the straight groove area 13 of the superconducting micron wire 12 single photon detector of the present invention, Figure 8 It can be seen that the surface undulation of the straight groove area 13 formed by the above-set parameters is less than 0.6 nm, and the depth of the groove is about 7 nm.

[0064] Specifically, ultraviolet exposure glue AZ703 is spin-coated on the surface of the superconducting wire, a Ti-Au cross is overlaid by an ultraviolet photolithography machine, the electrode pattern is prepared, and the device electrode is prepared by ion beam etching process. After the preparation is completed, it is sliced ​​to obtain the superconducting micron wire 12 single-photon detector of the present invention.

[0065] like Fig. 9 As shown in FIG. 1 , it shows the quantum efficiency of detecting 1550nm photons using a superconducting micron wire 12 with a straight groove region 13 and without a straight groove region 13. As can be seen from the figure, the quantum efficiency of the superconducting micron wire 12 without a straight groove region 13 is about 79%, while the quantum efficiency of the superconducting micron wire 12 is increased to 100% after etching the groove. Therefore, forming a straight groove region 13 with a certain width on the straight portion 121 can improve the quantum efficiency of the central area of ​​the superconducting micron wire 12.

[0066] In summary, the present invention provides a superconducting micron wire single-photon detection device and a preparation method thereof, which improves the quantum efficiency of the central area of ​​the superconducting micron wire by etching the straight portion of the superconducting micron wire, thereby forming a straight groove area and a transition area with a certain width and depth on the straight portion; and the formed straight groove area makes the cross-sectional area of ​​the straight portion of the superconducting micron wire smaller, resulting in a smaller current flux in the straight portion than the current flux in the corner area, thereby reducing the critical current of the straight portion, making the critical current of the straight portion lower than the critical value of the corner area, alleviating the "current crowding effect" caused by the high duty cycle in the corner area, and at the same time, setting the shape of the transition zone to an ellipse, which can avoid the current gathering caused by the sharp change of the cross-sectional area at the interface between the straight portion and the corner area, thereby improving the performance of the single-photon detection device; in addition, the single-photon detection device has a simple structure and is easy to expand into a detector with a large photosensitive area. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0067] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A superconducting micron wire single photon detection device, characterized in that: The single photon detection device at least comprises: A substrate and a superconducting micron-wire formed on the substrate, wherein the superconducting micron-wire comprises a plurality of straight portions and a curved corner region; Among them, the corner area is connected to the adjacent straight part end to end in sequence and the line width of the corner area is not less than the line width of the straight part, a straight groove area and a transition area are formed on the straight part, and the difference between the length of the straight part and the sum of the lengths of the straight groove area and the transition area is at least greater than twice the London penetration depth of the superconducting micron wire.

2. The superconducting micron wire single photon detection device according to claim 1, characterized in that: The plurality of straight line portions are arranged in parallel.

3. The superconducting micron wire single photon detection device according to claim 2, characterized in that: The shape of the transition zone is elliptical, and the ratio of the major axis to the minor axis of the transition zone is 1.5-4.

4. The superconducting micron wire single photon detection device according to claim 3, characterized in that: The width of the straight groove zone is greater than half of the width of the straight portion, there is a first distance between the upper edge of the straight groove zone and the corresponding upper edge of the straight portion, there is a second distance between the lower edge of the straight groove zone and the corresponding lower edge of the straight portion, and the first distance and the second distance are both greater than the London penetration depth of the superconducting micron wire.

5. The superconducting micron wire single photon detection device according to claim 4, characterized in that: The first distance and the second distance are equal in size.

6. The superconducting micron wire single photon detection device according to claim 4, characterized in that: The thickness of the straight portion is 3-15 nm, and the depth of the straight groove region is 50%-75% of the thickness of the straight portion.

7. A method for preparing a superconducting micron wire single-photon detection device, characterized in that: The preparation method comprises at least the following steps: Providing a substrate, and growing a superconducting thin film on the surface of the substrate; Spin-coating a photoresist on the superconducting film, and forming the superconducting micrometer line by exposure, development, etching and photoresist removal, wherein the superconducting micrometer line includes a plurality of straight sections and a curved corner area; Spin-coating photoresist on the superconducting micrometer wire again, and forming a straight groove area and a transition area on the straight line portion through exposure, development, etching and photoresist removal; Electrodes are prepared on the superconducting microwires.

8. The preparation method according to claim 7, characterized in that: The thickness of the superconducting film is 3-15 nm, the thickness of the straight portion is 3-15 nm, and the depth of the straight groove region is 50%-75% of the thickness of the straight portion.

9. The preparation method according to claim 7, characterized in that: The method of forming the superconducting thin film includes a DC magnetron sputtering method.

10. The preparation method according to claim 7, characterized in that: The material of the superconducting film includes one of NbN, Nb, NbSi, WSi, TaN, MoSi or NbTiN.

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