Orbital angular momentum on-chip detector and preparation method, detection device and photon chip

Abstract

The application discloses an on-chip detector for orbital angular momentum, a preparation method, a detection device and a photon chip. The on-chip detector for orbital angular momentum comprises a transparent base component and nanowires. A first surface of the transparent base component has a film layer, a plurality of arc-shaped nanoslit are penetrated through the film layer, the plurality of arc-shaped nanoslit form an plasmonic metasurface structure, and the plurality of arc-shaped nanoslit are arranged at intervals. The number of the nanowires is multiple, and the multiple nanowires are arranged at intervals on the film layer. The nanowires are perovskite nanowires. The on-chip detector for orbital angular momentum of the application can selectively excite a single transverse laser mode in the nanowire through subwavelength focusing of an orbital angular momentum plasmonic field, realize zero-mode crosstalk on-chip detection of the orbital angular momentum, and has extremely important significance for all-optical logic gates, ultrafast optical switches, nanophotonic detectors and on-chip optical and quantum information processing.

Description

Technical Field

[0001] This application relates to the field of orbital angular momentum detection technology, and in particular to an on-chip orbital angular momentum detector with zero-mode crosstalk, its fabrication method, detection device and photonic chip. Background Technology

[0002] Integrated photonic chips, using photons as information carriers, offer advantages such as high-speed parallelism and low power consumption, making them crucial for addressing future needs in low-power, high-speed, wide-bandwidth, and high-capacity information processing. High-performance photonic devices are currently a research hotspot in the field of photonic chips. The construction and control mechanisms of integrable photonic devices primarily involve manipulating and utilizing the physical dimensions of photons, such as frequency, wavelength, polarization, mode, and lifetime. Expanding the control dimensions, communication capacity, and bandwidth of semiconductor nanowire photonic devices based on existing optical interconnect and chip technologies is a major challenge and a key scientific question in the field of integrable photonic devices.

[0003] Photonic orbital angular momentum (OAM) possesses an infinitely orthogonal physical dimension. Therefore, utilizing orbital optical angular momentum as a new degree of freedom for information processing can significantly improve the control dimensionality and communication capacity of photonic devices. Research and development of high-performance photonic devices based on the orbital angular momentum dimension is also an emerging direction in the field of photonic communication. However, research on the application of orbital angular momentum in communication, especially its detection, still requires the use of large-size phase detection elements, such as spiral phase plates and spatial light modulators, which are difficult to integrate with highly integrated photonic chip technology. On-chip OAM detection technology utilizes plasmonic metal structures to convert the optical field carrying orbital angular momentum information into a surface plasmonic field. This results in very low detection efficiency (~10) due to significant losses caused by interband transitions within the metal. -6 This hinders the further development of the performance of integrable photonic devices and chips by utilizing photonic angular momentum modulation. Summary of the Invention

[0004] Therefore, addressing the problem that traditional technologies struggle to integrate orbital angular momentum with highly integrated photonic chip technology, hindering the further development of performance control for integrable photonic devices and chips using photonic angular momentum, it is necessary to provide a zero-mode-crosstalk on-chip orbital angular momentum detector. This invention's zero-mode-crosstalk on-chip orbital angular momentum detector achieves zero-mode-crosstalk on-chip detection by selectively exciting a single transverse laser mode in a nanowire through subwavelength focusing of an orbital angular momentum plasma field. This has significant implications for all-optical logic gates, ultrafast optical switches, nanophotonic detectors, on-chip optics, and quantum information processing.

[0005] One embodiment of this application provides an on-chip orbital angular momentum detector with zero-mode crosstalk.

[0006] A zero-mode crosstalk on-chip orbital angular momentum detector includes a transparent substrate and nanowires. The first surface of the transparent substrate has a film layer with multiple arc-shaped nanoslits running through it. The multiple arc-shaped nanoslits form a plasmonic metasurface structure and are spaced apart. There are multiple nanowires, which are spaced apart on the film layer. The nanowires are perovskite nanowires.

[0007] In some embodiments, the nanoslits are semi-circular arc-shaped, and the multiple nanoslits of the plasmonic metasurface structure form a concentric arc. At least one nanowire is provided on each side of the center of the plasmonic metasurface structure, and the end of the nanowire faces the center of the plasmonic metasurface structure.

[0008] In some embodiments, the nanowires are at an angle of 60° to 70° to the normal axis of the concentric arcs of the plasmon metasurface structure.

[0009] In some embodiments, the film layer is a silver film;

[0010] And / or, the thickness of the film layer is 200–300 nm.

[0011] In some embodiments, the nanoslit has a depth of 200–300 nm, a width of 150–200 nm, a period of 450–600 nm, an initial radius of 1575–1800 nm, and a depth of 200–300 nm.

[0012] In some embodiments, the nanowires have a width of 200–1200 nm and a length of 2–30 μm.

[0013] One embodiment of this application also provides a method for fabricating an on-chip detector with zero-mode crosstalk orbital angular momentum.

[0014] A method for fabricating an on-chip orbital angular momentum detector with zero-mode crosstalk includes the following steps:

[0015] Preparation of the film layer; the preparation method of the film layer is as follows: under vacuum conditions, silver particles are evaporated onto a transparent substrate component through a thermal evaporation coating system and condensed into a film to form the film layer;

[0016] A plasmonic metasurface structure was fabricated on the film layer, and the plasmonic metasurface was obtained by etching multiple arc-shaped nano-slits on the film layer using a focused ion beam.

[0017] The nanowires are transferred to a predetermined position on the plasmonic metasurface using an optical fiber probe.

[0018] In some embodiments, the method for preparing the film layer includes the following steps:

[0019] Silver particles are evaporated onto the surface of a transparent substrate and condensed into a film layer under vacuum conditions using a thermal evaporation coating system. The basic vacuum level of the coating chamber of the thermal evaporation coating system is 2 × 10⁻⁶. -4 ~3×10 -4 Pa; the evaporation rate of silver particles remained at 0.2–1 nm / s.

[0020] In some embodiments, the surface roughness of the quartz substrate is 0.1–0.5 nm; and / or the purity of the silver particles is ≥99.999%.

[0021] In some embodiments, the method for preparing the plasmonic metasurface structure includes the following steps:

[0022] Multiple nano-slits are obtained by focused plasma etching on the film layer, wherein the etching voltage is 10kV to 30kV, the etching current is 2pA to 5nA, the etching depth is 200 to 30nm, the etching width is 150 to 200nm, the period is 450 to 600nm, and the initial radius is 1575 to 1800nm.

[0023] In some embodiments, the method for preparing the nanowires includes the following steps: preparing them using chemical vapor deposition.

[0024] In some embodiments, the method for preparing the nanowires includes the following steps:

[0025] CsBr powder and PbBr2 powder were mixed at a mass ratio of 1:1 and placed in a first ceramic boat. A SiO2 / Si substrate was placed in a second ceramic boat. The first ceramic boat was placed in the center of a quartz tube, which was then inserted into a tube furnace. The second ceramic boat was placed at the edge of the heating wire of the tube furnace for sample deposition. High-purity argon gas was introduced into the quartz tube as a carrier gas. The high-purity argon gas was vented in the quartz tube at a flow rate of 1000–1500 sccm for 3–5 min, and then the flow rate was reduced to 30–60 sccm to grow the sample. The center of the tube furnace was heated from room temperature to 560°C–630°C within 20–30 min and held for 60–120 min. The gas pressure inside the quartz tube was maintained at 250–300 Torr. The tube furnace was then allowed to cool naturally to room temperature to obtain nanowires with a width of 200–1800 nm and a length of 2–30 μm.

[0026] In some embodiments, the method for preparing the nanowires further includes at least one of the following technical features:

[0027] (1) The purity of the CsBr powder is ≥99.999%;

[0028] (2) The purity of the PbBr2 powder is ≥99.999%;

[0029] (3) The purity of the high-purity argon gas is ≥99.999%.

[0030] In some embodiments, the method for preparing the nanowires further includes at least one of the following technical features:

[0031] (1) When growing samples, the flow rate was reduced to 40 sccm;

[0032] (2) The center of the tube furnace is heated from room temperature to 580°C within 20 minutes;

[0033] (3) The holding time is 80 minutes;

[0034] (4) The air pressure inside the quartz tube is maintained at 260 Torr.

[0035] An embodiment of this application also provides a detection device.

[0036] A detection device for on-plate detection of orbital angular momentum includes a pump source, a spatial light modulator, and an on-plate detector with zero-mode crosstalk. The pump source is used to provide a light source, and the spatial light modulator is used to modulate the Gaussian beam of the pump source into an arbitrary orbital angular momentum beam.

[0037] In some embodiments, the orbital angular momentum beam modulated by the spatial light modulator is converted into a surface plasmon field by a plasmon metasurface, and can excite a nanowire transverse laser mode under a specific orbital angular momentum mode.

[0038] In some embodiments, the wavelength of the pump light source is 470–500 nm.

[0039] One embodiment of this application also provides a photonic chip.

[0040] A photonic chip including an on-chip detector for orbital angular momentum with zero-mode crosstalk.

[0041] The aforementioned zero-mode-crosstalk on-chip orbital angular momentum detector achieves zero-mode-crosstalk on-chip detection by selectively exciting a single transverse laser mode in a nanowire through subwavelength focusing of the orbital angular momentum plasma field. This invention successfully fabricates a micro / nano-sized zero-mode-crosstalk on-chip orbital angular momentum detector by combining plasmonic metasurface structures with semiconductor nanowires, effectively solving the challenges of on-chip decoding and detection of OAM multiplexed signals and promoting the application value of photonic orbital angular momentum in the field of photonic chips.

[0042] In the aforementioned detection device, the pump light from the pump source is converted into an orbital angular momentum beam by a spatial light modulator and focused onto the back of the plasmonic metasurface by a 10x objective lens. The orbital angular momentum field of the plasmonic metasurface is converted into a plasmonic field to selectively excite the nanowires. After the signal is collected by a 100x objective lens, the photoluminescence signal of the nanowires can be monitored in real time by a microscope (e.g., a WITec alpha-300 confocal microscope). Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0045] Figure 1 This is a schematic diagram of an on-chip detector for orbital angular momentum with zero-mode crosstalk according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the fabrication and transfer method of the zero-mode crosstalk on-chip detector for orbital angular momentum according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of an on-chip detection device for zero-mode crosstalk orbital angular momentum according to an embodiment of the present invention;

[0048] Figure 4 Simulation of the electric field distribution of the zero-mode crosstalk on-chip detector for orbital angular momentum as described in an embodiment of the present invention;

[0049] Figure 5(a) is a SEM image of the zero-mode crosstalk on-chip detector for orbital angular momentum prepared in Example 1 of the present invention;

[0050] Figure 5(b) Dark field image of the zero-mode crosstalk on-chip detector prepared in Example 1 under 470nm wavelength excitation;

[0051] Figure 6 The spectral signal collected by the zero-mode crosstalk on-chip detector of the orbital angular momentum plate prepared in Embodiment 1 of the present invention;

[0052] Figure 7 The reflection spectrum of the plasmon metasurface structure simulated in Embodiment 2 of the present invention;

[0053] Figure 8 The electric field simulation of different periodic plasmon metasurface structures obtained in Embodiment 2 of the present invention is shown.

[0054] Figure 9 The electric field distribution of the nanowire and plasmon field at different distances obtained in Example 2 of this invention is shown.

[0055] Figure 10 This is a statistical chart of laser thresholds for nanowires of different widths obtained in Example 3 of the present invention.

[0056] Explanation of reference numerals in the attached figures

[0057] 10. On-chip detector with zero-mode crosstalk orbital angular momentum; 100. Film layer; 101. Nanoslit; 200. Nanowire. Detailed Implementation

[0058] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention 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 invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0061] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0063] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0065] This application provides a zero-mode crosstalk on-chip orbital angular momentum detector 10 to address the problem that existing conventional technologies struggle to integrate orbital angular momentum with highly integrated photonic chip technology, hindering the further development of performance control for integrable photonic devices and chips using photonic angular momentum. The zero-mode crosstalk on-chip orbital angular momentum detector 10 will be described below with reference to the accompanying drawings.

[0066] The zero-mode crosstalk on-chip detector 10 provided in this application embodiment is exemplary; please refer to [link to example]. Figure 1 As shown, Figure 1This is a schematic diagram of the structure of the zero-mode crosstalk orbital angular momentum on-chip detector 10 provided in an embodiment of this application. The zero-mode crosstalk orbital angular momentum on-chip detector 10 of this application can be used for chip fabrication. This invention is of great significance for all-optical logic gates, ultrafast optical switches, nanophotonic detectors, and on-chip optics and quantum information processing.

[0067] To more clearly illustrate the structure of the zero-mode crosstalk on-chip detector 10, the following will describe the zero-mode crosstalk on-chip detector 10 in conjunction with the accompanying drawings.

[0068] For example, please refer to Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of the zero-mode crosstalk on-chip detector 10 provided in an embodiment of this application.

[0069] One embodiment of this application provides an on-chip detector 10 for orbital angular momentum with zero-mode crosstalk.

[0070] A zero-mode crosstalk on-chip orbital angular momentum detector 10 includes a transparent substrate and nanowires 200. The first surface of the transparent substrate has a film layer 100, through which multiple arc-shaped nanoslits 101 are arranged, forming a plasmonic metasurface structure. The multiple arc-shaped nanoslits 101 are spaced apart. The number of nanowires 200 is multiple, and the multiple nanowires 200 are spaced apart on the film layer 100. The nanowires 200 are perovskite nanowires 200.

[0071] The transparent substrate component can be a quartz substrate.

[0072] In some embodiments, the nanowire 200 is a perovskite nanowire 200.

[0073] The aforementioned zero-mode-crosstalk on-chip detector 10 selectively excites a single transverse laser mode in the nanowire 200 by subwavelength focusing of the orbital angular momentum plasma field, thus achieving zero-mode-crosstalk on-chip detection of orbital angular momentum. This invention successfully fabricates a micro / nano-sized zero-mode-crosstalk on-chip detector 10 for orbital angular momentum by combining a plasmonic metasurface structure with semiconductor nanowires 200, effectively solving the problem of on-chip decoding and detection of OAM multiplexed signals and promoting the application value of photonic orbital angular momentum in the field of photonic chips.

[0074] In some embodiments, the nanoslits 101 are semi-circular arc-shaped, and the multiple nanoslits 101 of the plasmonic metasurface structure form concentric arcs. That is, from the inside to the outside, the radius of the nanoslits 101 gradually increases, and the different radii form an arithmetic sequence. At least one nanowire 200 is provided on each side of the center of the plasmonic metasurface structure, and the end of the nanowire 200 faces the center of the plasmonic metasurface structure.

[0075] In some embodiments, the nanowires 200 are at an angle of 60° to 70° to the normal axis of the concentric arcs of the plasmon metasurface structure.

[0076] In some embodiments, the film layer 100 is a silver film.

[0077] In some embodiments, the thickness of film 100 is 200–300 nm.

[0078] In some embodiments, the depth of the nanoslit 101 (i.e. the thickness of the film 100) is 200–300 nm, the width is 150–200 nm, the period is 450–600 nm, the initial radius is 1575–1800 nm, and the depth is 200–300 nm.

[0079] In some embodiments, the width of the nanowire 200 is 200–1200 nm, and the length of the nanowire 200 is 2–30 μm.

[0080] The zero-mode crosstalk on-chip detector 10 of this embodiment uses nanowires 200 with the chemical formula CsPbBr3 as the gain medium, which features low loss and high optical gain. Combined with an optimized plasmonic metasurface, the orbital angular momentum field can be converted into a subwavelength-limited and spatially-limited plasmonic field. This limited plasmonic field is further coupled to the end face of a single nanowire 200, enabling selective excitation of a single laser mode within the high-optical-gain nanowire 200. Through the structure of the plasmonic field and the semiconductor nanowire 200, the significant loss problem caused by inter-band transitions within the metal is solved, improving the on-chip detection efficiency of orbital angular momentum. In the zero-mode crosstalk on-chip detector 10 of this invention, the plasmonic field is super-diffraction-limited and spatially confined. Combined with the optimized nanowires 200, single-mode laser emission is achieved only under the excitation of a specific orbital angular momentum mode, while adjacent modes only exhibit spontaneous emission. Compared with the spectral intensity of spontaneous emission of adjacent modes, the dependence of a single-mode laser on the intensity of spontaneous emission can be calculated using formula (I), where (I) represents the intensity of the spectral signal and I represents the number of orbital angular momentum modes.

[0081]

[0082] One embodiment of this application also provides a method for fabricating an on-chip detector 10 with zero-mode crosstalk orbital angular momentum.

[0083] A method for fabricating an on-chip orbital angular momentum detector 10 with zero-mode crosstalk includes the following steps:

[0084] Prepare film layer 100; the method for preparing film layer 100 is as follows: under vacuum conditions, silver particles are evaporated onto a transparent substrate component by a thermal evaporation coating system and condensed into a film to form film layer 100;

[0085] A plasmonic metasurface structure is prepared on the film layer 100. The plasmonic metasurface is obtained by etching multiple arc-shaped nano-slits 101 on the film layer 100 using a focused ion beam.

[0086] The nanowire 200 is transferred to a predetermined position on the plasmonic metasurface using an optical fiber probe.

[0087] In some embodiments, the method for preparing film 100 includes the following steps:

[0088] Silver particles are evaporated onto the surface of a transparent substrate, such as a quartz substrate, under vacuum conditions using a thermal evaporation coating system, and condensed into a film layer 100. The basic vacuum level of the coating chamber of the thermal evaporation coating system is 2 × 10⁻⁶. -4 ~3×10 -4 Pa; the evaporation rate of silver particles remained at 0.2–1 nm / s.

[0089] In some embodiments, the surface roughness of the quartz substrate is 0.1–0.5 nm; and / or the purity of the silver particles is ≥99.999%.

[0090] In some embodiments, the method for preparing plasmon metasurface structures includes the following steps:

[0091] Multiple nano-slits 101 are obtained by focused plasma etching on the film layer 100, wherein the etching voltage is 10kV to 30kV, preferably 30kV; the etching current is 2pA to 5nA, preferably 7.7pA; the etching depth is 200 to 30nm; the etching width is 150 to 200nm; the period is 450 to 600nm; and the initial radius is 1575 to 1800nm.

[0092] In some embodiments, the preparation method of nanowire 200 (chemical formula CsPbBr3) includes the following steps: it is prepared by chemical vapor deposition.

[0093] In some embodiments, the preparation method of the nanowire 200 includes the following steps:

[0094] CsBr powder and PbBr2 powder were mixed at a mass ratio of 1:1 and placed in a first ceramic boat. A SiO2 / Si substrate was placed in a second ceramic boat. The first ceramic boat was placed in the center of a quartz tube, which was then inserted into a tube furnace. The second ceramic boat was placed at the edge of the heating wire of the tube furnace for sample deposition. High-purity argon gas was introduced into the quartz tube as a carrier gas. The high-purity argon gas was vented in the quartz tube at a flow rate of 1000–1500 sccm for 3–5 min, and then the flow rate was reduced to 30–60 sccm to grow the sample. The center of the tube furnace was heated from room temperature to 560℃–630℃ over 20–30 min and held for 60–120 min. The gas pressure inside the quartz tube was maintained at 250–300 Torr. The tube furnace was then allowed to cool naturally to room temperature to obtain nanowires 200 with a width of 200–1800 nm and a length of 2–30 μm.

[0095] In some of these embodiments, both the CsBr powder and the PbBr2 powder are selected from Alfa Aesar.

[0096] In some embodiments, the method for preparing the nanowires 200 further includes at least one of the following technical features:

[0097] (1) The purity of CsBr powder is ≥99.999%;

[0098] (2) The purity of PbBr2 powder is ≥99.999%;

[0099] (3) The purity of high-purity argon gas is ≥99.999%.

[0100] In some embodiments, the method for preparing the nanowires 200 further includes at least one of the following technical features:

[0101] (1) When growing samples, the flow rate was reduced to 40 sccm;

[0102] (2) The center of the tube furnace is heated from room temperature to 580°C within 20 minutes;

[0103] (3) The holding time is 80 minutes;

[0104] (4) The air pressure inside the quartz tube is maintained at 260 Torr.

[0105] An embodiment of this application also provides a detection device.

[0106] A detection device for on-chip detection of orbital angular momentum includes a pump source, a spatial light modulator, and an on-chip detector 10 with zero mode crosstalk. The pump source is used to provide a light source, and the spatial light modulator is used to modulate the Gaussian beam of the pump source into an arbitrary orbital angular momentum beam.

[0107] In some of these embodiments, see Figure 3 As shown, the detection device also includes a half-wave plate, a linear polarizer, a convex lens, a reflecting mirror, a polarizing beam splitter, a quarter-wave plate, and a first objective lens (with attachment). Figure 3 The image shows objective lens 1 and the second objective lens (attached). Figure 3 The diagram shows one or more of the following: objective lens 2), a semi-reflective mirror, an image acquisition component, and a spectrometer. Along the incident direction of the light path, a half-wave plate, a linear polarizer, a convex lens, and a mirror are arranged. A spatial light modulator and a polarizing beam splitter are positioned opposite each other to modulate the Gaussian beam of the pump source into a beam with arbitrary orbital angular momentum. Along the reflection direction of the light path, a polarizing beam splitter, a quarter-wave plate, a first objective lens, a second objective lens, and a semi-reflective mirror are arranged. The image acquisition component and the spectrometer are respectively positioned along the transmission and reflection directions of the semi-reflective mirror. A zero-mode-crosstalk on-plate detector 10 is positioned between the first and second objective lenses, with the transparent substrate of the zero-mode-crosstalk on-plate detector 10 facing the first objective lens and the film layer 100 facing the second objective lens.

[0108] In some embodiments, the image acquisition component may be a CCD industrial camera or a microscope, such as the WITec alpha-300 confocal microscope.

[0109] In some embodiments, the first objective lens may be a 10x 0.45 objective lens with a numerical aperture of 0.45. The second objective lens may be a 100x 0.95 objective lens with a numerical aperture of 0.95.

[0110] In some embodiments, the wavelength of the pump light source is 470–500 nm.

[0111] In some embodiments, the orbital angular momentum beam modulated by the spatial light modulator is converted into a surface plasmon field by a plasmon metasurface, and can excite a nanowire transverse laser mode under a specific orbital angular momentum mode.

[0112] In the aforementioned detection device, the pump light from the pump source is converted into an orbital angular momentum beam by a spatial light modulator, see [link to relevant documentation]. Figure 1 As shown, by focusing a 10x objective lens onto the back of the plasmonic metasurface, the orbital angular momentum field of the plasmonic metafront is converted into a plasmonic field to selectively excite the nanowire 200. After collecting the signal with a 100x objective lens, the photoluminescence signal of the nanowire 200 can be monitored in real time by an image acquisition component such as a microscope, for example, a WITec alpha-300 confocal microscope.

[0113] One embodiment of this application also provides a photonic chip.

[0114] A photonic chip including a zero-mode crosstalk orbital angular momentum on-chip detector 10.

[0115] Example 1

[0116] This embodiment provides a zero-mode crosstalk on-chip orbital angular momentum detector 10, including a transparent substrate, a film layer 100, and nanowires 200. The film layer 100 has a thickness of 200 nm. The first surface of the transparent substrate has the film layer 100, and multiple arc-shaped nanoslits 101 penetrate the film layer 100, forming a plasmonic metasurface structure. The nanoslits 101 have a depth of 200 nm, a width of 150 nm, a period of 450 nm, and an initial radius of 1575 nm.

[0117] Five nanowires 200 are spaced apart on the plasmonic metasurface. The width of each nanowire 200 ranges from 200 to 1200 nm, and its length ranges from 2 to 30 μm. The nanoslits 101 are semi-circular in shape, forming concentric arcs. A nanowire 200 is positioned on each side of the center of the plasmonic metasurface structure, with the ends of the nanowires facing the center. Each nanowire 200 forms a 60° angle with the normal axis of the concentric arc of the plasmonic metasurface structure.

[0118] The zero-mode crosstalk on-chip orbital angular momentum detector 10 described above is fabricated using the following method. For a method of fabricating the zero-mode crosstalk on-chip orbital angular momentum detector 10, please refer to [link to documentation]. Figure 2 As shown, it includes the following steps:

[0119] Step 1: Prepare film layer 100; Select a quartz substrate with a surface roughness of 0.1 nm, and under vacuum conditions, evaporate silver particles onto the surface of the quartz substrate using a thermal evaporation coating system to condense them into film layer 100. The basic vacuum degree of the coating chamber of the thermal evaporation coating system is 2 × 10⁻⁶. -4 Pa; wherein the evaporation rate of the silver particles is maintained at 0.2 nm / s, and the purity of the silver particles is ≥99.999%.

[0120] Step 2: A plasmonic metasurface structure is fabricated on film layer 100 using a focused ion beam. The fabrication method of the plasmonic metasurface structure includes the following steps: five nano-slits 101 are obtained by focused plasma etching on film layer 100, wherein the etching voltage is 30 kV, the etching current is 7.7 pA, the etching depth is 200 nm, the etching width is 150 nm, the period is 450 nm, and the initial radius is 1575 nm. Please refer to Figure 5 for the SEM image of the plasmonic metasurface structure.

[0121] Step 3: Nanowires 200 are prepared using chemical vapor deposition. The preparation method of nanowires 200 includes the following steps:

[0122] Purchased from Alfa Aesar's CsBr powder and PbBr2 powder with a purity ≥99.999% were mixed in a 1:1 mass ratio and placed in a first ceramic boat. A SiO2 / Si substrate was placed in a second ceramic boat. The first ceramic boat was placed in the center of a quartz tube, which was then inserted into a tube furnace. The second ceramic boat was placed at the edge of the heating wire of the tube furnace for sample deposition. High-purity argon gas was introduced into the quartz tube as a carrier gas. High-purity argon gas with a purity ≥99.999% was purged in the quartz tube at a flow rate of 1000–1500 sccm for 3–5 min, and then the flow rate was reduced to 40 sccm to grow the sample. The center of the tube furnace was heated from room temperature to 580°C within 20 min and held for 80 min, while the gas pressure inside the quartz tube was maintained at 260 Torr. The tube furnace was then allowed to cool naturally to room temperature, yielding nanowires with the chemical formula CsPbBr3, a width of 200–1800 nm, and a length of 2–30 μm.

[0123] Step 4: Transfer two 500nm wide nanowires 200 to the predetermined positions on the plasmonic metasurface using an optical fiber probe. One end of each nanowire 200 is positioned on either side of the center of the concentric arc of the plasmonic metasurface structure, forming a 60° angle with the normal axis of the concentric arc. The specific placement is as follows: Figure 4 Electric field distribution in the middle,

[0124] In Example 1, referring to Figure 5(a), which is a SEM image of the on-chip detector 10 with zero-mode crosstalk, it can be seen from Figure 5(a) that the surface of the nanowire 200 after transfer is relatively smooth. Figure 3 CCD imaging in the detection device shows that at l = +3, the fluorescence intensity of the second nanowire 200 (labeled as nanowire 2 in Figure 5(b)) is much stronger than that of the first nanowire 200 (labeled as nanowire 1 in Figure 5(b)), while at l = -4, the fluorescence intensity of the first nanowire 200 is much stronger than that of the second nanowire 200. The spectra of the first and second nanowires 200 under excitation with beams of 1.3 times the threshold power and different orbital angular momentum were monitored using a spectrometer. See [reference needed]. Figure 6 As shown, Figure 6 The horizontal axis represents wavelength, from Figure 6 It can be seen that the first nanowire 200 and the second nanowire 200 generated laser signals only when l = +3 and l = -4, and the intensity was much greater than the spectral intensity when excited by other orbital angular momentum modes.

[0125] For simulation experiments on the optimization of the plasmon metasurface structure in this embodiment, please refer to [link / reference]. Figure 7 As shown, Figure 7 The horizontal axis represents wavelength; Figure 7 The reflection spectra are shown for the presence of a plasmonic metasurface structure (solid line at the bottom) and the absence of a plasmonic metasurface structure (dashed line at the top) under varying wavelength excitation. The reflection spectrum is lowest at 470 nm, proving that the plasmonic metasurface structure prepared in this embodiment resonates at this wavelength of 470 nm and has the strongest plasmonic field conversion efficiency.

[0126] Example 2

[0127] This embodiment provides a zero-mode crosstalk on-chip detector 10 for orbital angular momentum. The zero-mode crosstalk on-chip detector 10 in this embodiment is basically the same as that in Embodiment 1, except that the width of the nanowire 200 is different.

[0128] This embodiment tests the effect of different widths of the nanowires 200 on the lasing threshold. Since the plasmonic field excites the lateral laser mode of the tackey metal nanowires 200, the lateral width of the tackey metal nanowires 200 affects the coupling efficiency, leading to different lasing thresholds. This also affects the energy efficiency of the detection device during detection, such as... Figure 10 As shown, Figure 10 In the figure, the horizontal axis represents the width of the titanium dioxide nanowire 200. Within the test range, the smaller the width of the titanium dioxide nanowire 200, the lower the laser threshold.

[0129] Comparative Example 1

[0130] This comparative example provides a zero-mode crosstalk on-chip detector 10 for orbital angular momentum. The zero-mode crosstalk on-chip detector 10 of this comparative example is basically the same as that of Example 1, except that the period of the plasmonic metasurface is different.

[0131] Figure 8 For different periods ( Figure 8 A comparison of the plasmonic electric field intensity generated by the plasmonic metasurface structure at the mid-pitch (pitch) time. The electric field intensity is maximum when the period is close to the plasmonic wavelength. Figure 8 It can be seen that the electric field strength is strongest at the 450nm period set in Example 1.

[0132] Comparative Example 2

[0133] This embodiment provides a zero-mode crosstalk orbital angular momentum on-chip detector 10. The zero-mode crosstalk orbital angular momentum on-chip detector 10 in this embodiment is basically the same as that in Embodiment 1. The difference between the two embodiments is that the etching depth of the nano-slits 101 of the plasmonic metasurface structure is different.

[0134] See also Figure 3 As shown, since Example 1 uses back-side excitation from the plasmonic metasurface structure, when the etching depth of the nano-slits 101 of the plasmonic metasurface structure is less than the thickness of the film layer 100, it is difficult for the plasmonic field to form on the surface of the film layer 100. That is to say, in Example 1, the etching depth must penetrate the entire film layer 100 to achieve the formation of the plasmonic field.

[0135] Comparative Example 3

[0136] This embodiment provides a zero-mode crosstalk on-chip detector 10 for orbital angular momentum. The zero-mode crosstalk on-chip detector 10 in this embodiment is basically the same as that in Embodiment 1, except that the distance between the tantalum nanowire 200 and the plasmonic field is different.

[0137] See Figure 9 As shown, the plasmonic field is strongest at the center of the concentric arc of the plasmonic metasurface structure. When the tackie metal nanowires 200 are far from the center of the concentric arc of the plasmonic field, it is difficult to couple energy into the tackie metal nanowires 200.

[0138] In summary, the aforementioned zero-mode crosstalk on-chip detector 10 selectively excites a single transverse laser mode in the nanowire 200 by subwavelength focusing of the orbital angular momentum plasma field, thus achieving zero-mode crosstalk on-chip detection of orbital angular momentum. This effectively solves the problem of on-chip decoding and detection of OAM multiplexed signals and promotes the application value of photonic orbital angular momentum in the field of photonic chips.

[0139] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0140] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0141] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A zero-mode crosstalk on-chip orbital angular momentum detector, characterized in that, The device includes a transparent substrate component and nanowires. The first surface of the transparent substrate component has a film layer with multiple arc-shaped nanoslits running through it. The multiple arc-shaped nanoslits form a plasmonic metasurface structure and are spaced apart. The device contains multiple nanowires, which are spaced apart on the film layer. The nanowires are perovskite nanowires.

2. The zero-mode crosstalk on-chip orbital angular momentum detector according to claim 1, characterized in that, The nanoslits are semi-circular arc-shaped, and the multiple nanoslits of the plasmonic metasurface structure form a concentric arc. At least one nanowire is provided on each side of the center of the plasmonic metasurface structure, and the end of the nanowire faces the center of the plasmonic metasurface structure.

3. The zero-mode crosstalk on-chip orbital angular momentum detector according to claim 2, characterized in that, The nanowires form an angle of 60° to 70° with the normal axis of the concentric arc of the plasmon metasurface structure.

4. The zero-mode crosstalk on-chip orbital angular momentum detector according to any one of claims 1-3, characterized in that, The width of the nanoslit is 150 ~ 200 nm, the period is 450 ~ 600 nm, the initial radius is 1575 ~ 1800 nm, and the depth is 200 ~ 300 nm.

5. A method for fabricating an on-chip detector with zero-mode crosstalk as described in any one of claims 1-4, characterized in that, Includes the following steps: Preparation of the film layer; the preparation method of the film layer is as follows: under vacuum conditions, silver particles are evaporated onto a transparent substrate component through a thermal evaporation coating system and condensed into a film to form the film layer; A plasmonic metasurface structure was fabricated on the film layer, and the plasmonic metasurface was obtained by etching multiple arc-shaped nano-slits on the film layer using a focused ion beam. The nanowires are transferred to a predetermined location on the plasmonic metasurface using an optical fiber probe.

6. The method for fabricating a zero-mode crosstalk on-chip orbital angular momentum detector according to claim 5, characterized in that, The method for preparing the nanowires includes the following steps: CsBr powder and PbBr2 powder were mixed at a mass ratio of 1:1 and placed in a first ceramic boat. A SiO2 / Si substrate was placed in a second ceramic boat. The first ceramic boat was placed in the center of a quartz tube, which was then inserted into a tube furnace. The second ceramic boat was placed at the edge of the heating wire of the tube furnace for sample deposition. High-purity argon gas was introduced into the quartz tube as a carrier gas. The high-purity argon gas was vented in the quartz tube at a flow rate of 1000-1500 sccm for 3-5 minutes, and then the flow rate was reduced to 30-60 sccm to grow the sample. The center of the tube furnace was heated from room temperature to 560-630°C within 20-30 minutes and held for 60-120 minutes. The gas pressure inside the quartz tube was maintained at 250-300 Torr. The tube furnace was then allowed to cool naturally to room temperature to obtain nanowires with a width of 200-1800 nm and a length of 2-30 μm.

7. The method for fabricating an on-chip detector with zero-mode crosstalk according to claim 6, characterized in that, The method for preparing the nanowires further includes at least one of the following technical features: (1) When growing samples, the flow rate was reduced to 40 sccm; (2) The center of the tubular furnace is heated from room temperature to 580°C within 20 minutes; (3) The holding time is 80 min; (4) The air pressure inside the quartz tube is maintained at 260 Torr.

8. A detection device for use in detecting orbital angular momentum plates, characterized in that, The device includes a pump source, a spatial light modulator, and an on-chip detector with zero-mode crosstalk prepared by the method described in any one of claims 1-4 or any one of claims 5-7. The pump source is used to provide a light source, and the spatial light modulator is used to modulate the Gaussian beam of the pump source into an arbitrary orbital angular momentum beam.

9. The detection device according to claim 8, characterized in that, The orbital angular momentum beam modulated by the spatial light modulator is converted into a surface plasmon field by the plasmon metasurface, and can excite the transverse laser mode of nanowires under a specific orbital angular momentum mode.

10. A photonic chip, characterized in that, The on-chip orbital angular momentum detector with zero mode crosstalk is prepared by the method described in any one of claims 1-4 or any one of claims 5-7.

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