Local oscillator near-field electromagnetic field regulating device and method

Abstract

The application provides a local oscillator near-field electromagnetic field regulating device and method, and belongs to the technical field of quantum sensing and electromagnetic measurement. The local oscillator near-field electromagnetic field regulating device comprises, from bottom to top, a metal floor layer, a substrate layer and a metal layer. The metal layer is composed of an asymptote and a periodic structure. The periodic structure is composed of a plurality of periodic unit structure arrays with the same structure, and N ports are arranged between adjacent periodic unit structures. The regulating method is realized based on a Rydberg atom receiving system and the local oscillator near-field electromagnetic field regulating device. The local oscillator near-field electromagnetic field regulating device is applied to the Rydberg atom receiving system to provide a stable and controllable local oscillator electromagnetic field for the atomic mixing process. The application can regulate the near-field distribution of electromagnetic waves in the atomic chamber, realize the accurate and controllable adjustment of the near-field electric field in the confinement space, and is beneficial to improving the sensitivity and expandability of the system.

Description

Technical Field

[0001] This invention belongs to the field of quantum sensing and electromagnetic measurement technology, and relates to a local oscillator near-field electromagnetic field control device and method, particularly to a local oscillator near-field electromagnetic field control device and method applied to a superheterodyne Rydberg atom receiving system. Background Technology

[0002] In recent years, electromagnetic field detection and reception technology based on Rydberg atoms has gradually become an important research direction in the field of quantum sensing and electromagnetic measurement due to its advantages in wide bandwidth coverage, high sensitivity, and traceable quantum metrology. By utilizing the strong response characteristics of Rydberg atoms to electric fields, combined with EIT modulation spectrum and Autler–Townes split spectrum, high-resolution measurement of weak electric fields of external electromagnetic signals can be achieved. The proposed superheterodyne receiver architecture generates intermediate frequency signals through the nonlinear interaction between the local oscillator electromagnetic field and the measured signal in the atomic system, providing an effective means to improve the system signal-to-noise ratio, extend the dynamic range, and realize complex signal processing. Therefore, the superheterodyne Rydberg atom receiving system is considered one of the important technical routes for realizing novel quantum receivers.

[0003] In existing superheterodyne Rydberg atom receiving systems, the local oscillator electromagnetic field is typically introduced via an external antenna, waveguide, or free-space radiation, acting on the atomic gas cell at a certain distance. These schemes often rely on far-field or quasi-far-field radiation assumptions, approximating the region of the atomic gas cell as a uniform field irradiated by a plane wave. However, as systems evolve towards miniaturization and integration, the spatial distance between the local oscillator radiation structure and the atomic gas cell needs to be further reduced, causing the atomic system to operate in the near-field region of the radiation structure. Under near-field conditions, the electromagnetic field inevitably exhibits significant spatial inhomogeneity, wavefront bending, and rapid amplitude changes. This leads to inconsistencies in the local oscillator field strength and phase experienced by atoms at different spatial locations within the gas cell, thereby compromising the atomic system's requirements for the coherence and uniformity of the local oscillator field. Consequently, this affects the stability of the superheterodyne mixing process, reducing the resolvable scale and effective response range of the atomic system.

[0004] To address the impact of the local oscillator's near-field electromagnetic environment on system performance, some research and patents have proposed solutions. For example, Chinese invention patent 202311871439.7 proposes a field strength coupling method, system, and device for Rydberg atomic field strength measurement. By constructing an internal calibration factor, it achieves a quantitative mapping relationship between the superheterodyne output signal and the absolute electric field strength, which has positive significance in terms of measurement accuracy and traceability. However, this type of technical solution mainly focuses on the calibration and value coupling of measurement results, without addressing the miniaturization and integration of the superheterodyne local oscillator structure, and even less on actively controlling the distribution characteristics of the local oscillator's near-field electromagnetic field within the atomic interaction region under superheterodyne operating conditions, starting from the electromagnetic radiation structure itself.

[0005] In practical systems, the spatial non-uniformity, amplitude fluctuations, and insufficient coherence of the local oscillator's near-field electromagnetic field still directly affect the response uniformity and superheterodyne mixing stability of the atomic system. Existing technologies primarily address these issues by increasing the local oscillator power, widening the distance between the local oscillator radiation structure and the atomic gas cell, or introducing complex three-dimensional cavities or shielding structures to create a relatively uniform electromagnetic field distribution within the atomic region. However, these methods often lead to a significant increase in system volume and structural complexity, and it is difficult to simultaneously meet the requirements of field strength enhancement and spatial uniformity control under near-field operating conditions.

[0006] Therefore, how to effectively control the local oscillator near-field electromagnetic field distribution characteristics in a superheterodyne Rydberg atom receiving system within a limited spatial scale, so that it simultaneously meets the requirements of field strength, uniformity and coherence within the atomic interaction region, remains a key technical problem that has not yet been solved in the current technology. Summary of the Invention

[0007] This invention addresses the problem in existing superheterodyne Rydberg atom receiving systems where the local oscillator electromagnetic field (LOE) struggles to simultaneously satisfy the requirements of field strength enhancement, spatial uniformity, and coherence under near-field conditions. It proposes a device and method for controlling the LEE near-field electromagnetic field, specifically an LEE near-field electromagnetic field control device and method applied to superheterodyne Rydberg atom receiving systems. This invention introduces a pixelated LEE near-field radiation structure to control the near-field distribution of electromagnetic waves within the atomic gas chamber. Through multi-port lumped loading combined with a multi-objective optimization algorithm, precise and controllable adjustment of the near-field electric field within the constrained space is achieved. This allows for the formation of a relatively smooth phase change and spatially controllable LEE near-field electromagnetic field environment within the atomic interaction region, even when the atomic gas chamber and radiation structure are close together. This near-field electromagnetic field maintains good consistency and equivalent coherence within the effective response scale of the atomic system, meeting the requirements of superheterodyne Rydberg atom receiving systems for LEE field stability and mixing conditions, and improving the system's sensitivity and scalability.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A local oscillator near-field electromagnetic field modulation device, comprising, from bottom to top: a metal ground plane layer, a substrate layer, and a metal layer. The metal layer consists of two parts: an asymptote and a periodic structure. The periodic structure is composed of an array of multiple identical periodic unit structures, with N ports positioned between adjacent periodic unit structures. Specifically:

[0010] The metal floor layer is a continuous metal planar structure located at the bottom of the local oscillator near-field electromagnetic field control device. It is used to shield the electromagnetic field inside the local oscillator near-field electromagnetic field control device and provide a stable electromagnetic return path for high-frequency signals, thereby suppressing back radiation and stray coupling.

[0011] The substrate layer is disposed above and in close contact with the metal ground plane layer. The substrate layer is a dielectric material, and its dielectric constant and thickness determine the electromagnetic propagation characteristics of the local oscillator near-field electromagnetic field control device. The substrate layer provides electromagnetic isolation between the metal ground plane layer and the metal layer in the vertical direction.

[0012] The metal layer is disposed on the upper surface of the substrate layer. This continuous conductive metal layer serves as the primary carrier for the propagation and control of high-frequency electromagnetic waves in the local oscillator near-field electromagnetic field control device. Within this metal layer, the asymptote on the left and the periodic structure on the right are electrically connected, forming an integrated metal transmission structure. That is, the periodic structure formed by the periodic unit structure and the asymptote are spatially adjacent, enabling electromagnetic coupling. This allows the local oscillator signal propagating along the asymptote to excite the periodic unit structure to generate a local near-field response.

[0013] Furthermore, the asymptote extends along the transmission direction to guide the local oscillator signal to propagate within the local oscillator near-field electromagnetic field control device, and to excite a controlled near-field electromagnetic distribution around it; the orientation, width, and positional arrangement of the asymptote relative to the unit structure jointly determine the spatial distribution morphology of the local oscillator near-field. Furthermore, the periodic unit structures are arranged periodically along the transmission direction of the asymptote, with multiple periodic unit structures arranged sequentially to form a two-dimensional periodic structure.

[0014] Furthermore, each periodic unit structure is a square metal structure with port interface areas reserved inward on its four sides, so that while maintaining structural symmetry, the periodic unit structure can form a controllable electromagnetic coupling channel with adjacent periodic units.

[0015] Furthermore, N ports are provided, each positioned between two adjacent periodic unit structures and electrically connected to its corresponding port interface area. These ports are used to introduce lumped parameter loading elements, thereby altering the equivalent electromagnetic connection between adjacent periodic unit structures. The lumped parameter loading elements are electrically connected to their respective ports. By applying different loading states to different ports, the overall electromagnetic response of the periodic structure can be discretely controlled.

[0016] Furthermore, the port states of the N ports include open circuit, short circuit, capacitive loading, and inductive loading states. The capacitive and inductive loading states are both implemented using lumped capacitor or lumped inductor elements with actual physical parameter values. The open circuit state means that no electrical connection element is connected to the corresponding port location, maintaining electrical isolation between adjacent structural units. The short circuit state means that a low-impedance electrical connection path is formed at the corresponding port location, enabling electrical connection between adjacent structural units. By applying different port states to different ports, the equivalent capacitance, equivalent inductance, or coupling strength between corresponding periodic unit structures can be changed, thereby reconstructing the equivalent electromagnetic parameters of the periodic unit structure.

[0017] Furthermore, through-hole structures can be added to the periodic structure of the metal layer to expand the structural degrees of freedom for near-field electromagnetic control.

[0018] Furthermore, multiple stacked structures can be added above the metal layer to expand the operating bandwidth, control dimensions, and functional implementation methods of the local oscillator near-field electromagnetic field control device while maintaining the overall structural compactness, thereby achieving composite control of multi-frequency response, field distribution shaping, or near-field characteristics. Each stacked structure includes an intermediate dielectric layer and a top metal layer, wherein the intermediate dielectric layer is a dielectric material.

[0019] A method for controlling the local oscillator near-field electromagnetic field is disclosed, based on a Rydberg atom receiving system and the aforementioned local oscillator near-field electromagnetic field control device. The local oscillator near-field electromagnetic field control device is applied to the Rydberg atom receiving system to provide a stable and controllable local oscillator electromagnetic field for the atom mixing process. The method includes the following steps:

[0020] The first step involves constructing a coupling system between a Rydberg atom receiving system and a local oscillator near-field electromagnetic field control device to obtain a superheterodyne Rydberg atom receiving system. The local oscillator near-field electromagnetic field control device is located between the horn antenna and the sensing gas cell of the Rydberg atom receiving system, with the sensing gas cell situated above the metal layer of the local oscillator near-field electromagnetic field control device, and the horn antenna located to the side. Specifically:

[0021] The Rydberg atomic receiving system includes a laser optical system, a first wavelength laser frequency locking module, a second wavelength laser frequency locking module, an atomic sensing unit, a signal radiation unit, and a signal detection and processing unit. The laser optical system includes a first laser and a second laser, which are used to generate first wavelength laser and second wavelength laser, respectively.

[0022] The first wavelength laser output from the first laser is split into two laser beams after passing sequentially through a first optical isolator, a first half-wave plate, and a first polarization beam splitter, achieving optical isolation, polarization state adjustment, and optical path distribution. The first optical isolator prevents back-reflected light from entering the first laser, thereby improving laser output stability; the first half-wave plate adjusts the polarization direction of the incident light to control the splitting ratio of the subsequent first polarization beam splitter. After passing through the first polarization beam splitter, the first wavelength laser is split into two paths:

[0023] One laser beam split from the first polarization beam splitter enters the first wavelength laser frequency-locking module to construct the atomic reference signal and stabilize the frequency of the first wavelength laser. The other laser beam split from the first polarization beam splitter serves as the main probe beam path, passing sequentially through the first reflector, the second half-wave plate, the second polarization beam splitter, the third half-wave plate, and the first dichroic mirror. At the first dichroic mirror, it is split into two paths: one path enters the second light absorption terminal to absorb excess beams and eliminate stray interference; the other path serves as the probe beam and enters the sensing gas chamber.

[0024] The laser light entering the first-wavelength laser frequency-locking module passes sequentially through a fourth half-wave plate and a third polarization beam splitter. The fourth half-wave plate is used to adjust the polarization state, enabling the third polarization beam splitter to split the light according to a set ratio. After passing through the third polarization beam splitter, the light is divided into three paths: the first path enters the first photodetector, which converts the optical signal into an electrical signal to form the error signal required for the first-wavelength laser frequency locking; the second path enters the first-wavelength frequency-locking gas cell and reaches the beam splitter, where it interacts with atoms to form a frequency reference; the third path is guided to the second-wavelength laser frequency-locking module to assist in stabilizing the frequency of the second-wavelength laser. Thus, the fourth half-wave plate, the third polarization beam splitter, the first photodetector, the first-wavelength frequency-locking gas cell, and the beam splitter together constitute the first-wavelength laser frequency-locking module.

[0025] The second laser outputs a second wavelength laser beam, which also passes sequentially through a second optical isolator, a fifth half-wave plate, and a fourth polarization beam splitter. The second optical isolator is used to prevent feedback light from interfering with the stable output of the second laser; the fifth half-wave plate is used to adjust the polarization direction to control the splitting ratio of the fourth polarization beam splitter. After passing through the fourth polarization beam splitter, the second wavelength laser beam is split into two paths: the first path enters the second wavelength laser frequency-locking module; the second path is reflected by the second mirror and enters the main optical path of the coupling light. The beam entering the second wavelength laser frequency-locking module first reaches the third dichroic mirror, where it is split into two paths: the first path enters the second wavelength frequency-locking gas cell, interacts with atoms to form a frequency-locking reference signal, and the remaining light after passing through the second wavelength frequency-locking gas cell is guided by the fourth dichroic mirror to the first light absorption terminal for absorption; the second path is guided by the third dichroic mirror to the second photodetector, which is used to acquire the frequency-locking signal and generate an error signal, thereby achieving frequency stabilization of the second wavelength laser. Thus, the third dichroic mirror, the second wavelength frequency-locking gas chamber, the fourth dichroic mirror, the first light absorption terminal, and the second photodetector together constitute the second wavelength laser frequency-locking module.

[0026] The second-wavelength laser, reflected by the second mirror, passes sequentially through the sixth half-wave plate, the fifth polarizing beam splitter, the seventh half-wave plate, and the second dichroic mirror before entering the atom sensing unit as coupling light. The atom sensing unit includes a sensing gas chamber. The coupling light and the aforementioned probe light form a collinear propagation structure in opposite directions within the sensing gas chamber. The two laser beams act together on the Rydberg atomic system, creating an electromagnetically induced transparency effect under appropriate frequency conditions, thereby achieving a highly sensitive response to applied electromagnetic fields. The probe light, after passing through the sensing gas chamber, is guided by the second dichroic mirror to the third photodetector and further sent to the signal detection and processing unit for demodulation and analysis.

[0027] The signal radiation unit includes a signal source and a horn antenna. The horn antenna is electrically connected to the signal source and is used to generate the electromagnetic signal to be measured. The horn antenna converts the electrical signal to be measured into a free-space electromagnetic wave and radiates it to the region where the sensing chamber is located. Below the sensing chamber, a local oscillator near-field electromagnetic field control device proposed in this invention is arranged. The local oscillator near-field electromagnetic field control device is electrically connected to the signal source and is used to receive a stable local oscillator signal and generate a spatially controllable local oscillator near-field electromagnetic field in the atomic interaction region within the sensing chamber. The local oscillator near-field electromagnetic field interacts with the electromagnetic signal to be measured radiated into the sensing chamber by the horn antenna in the Rydberg atomic system, thereby achieving superheterodyne mixing during the atomic response process. The signal detection and processing unit includes a third photodetector and an oscilloscope, used to perform electrical signal conversion, demodulation, and analysis on the optical signal modulated by the Rydberg atomic system. The probe optical signal modulated by the Rydberg atoms is converted into an electrical signal by the third photodetector and finally sent to the oscilloscope for display, demodulation, or spectrum analysis.

[0028] Step 2: The local oscillator near-field electromagnetic field control device is electrically connected to the signal source in the coupling system constructed in Step 1 and is arranged below the sensing gas chamber. The near-field electromagnetic field it generates mixes with the signal to be measured in the atomic system. To optimize the performance of the system described in Step 1 under near-field operating conditions, the structural parameters of the local oscillator near-field electromagnetic field control device are parametrically modeled and optimized. The core is to introduce multiple controllable ports into the pre-designed local oscillator near-field electromagnetic field control device and to uniformly parametrically describe the electrical state and parameters of each port, providing a variable basis for subsequent electromagnetic simulation and optimization. Specifically:

[0029] Step 2.1: Introduce N ports into the local oscillator near-field electromagnetic field control device, where N is a positive integer. The N ports are respectively set between adjacent periodic unit structures to realize the adjustable loading of the equivalent electromagnetic parameters of the structure.

[0030] Step 2.2: Parameterize the port states of N ports, including open circuit state, short circuit state, capacitor-loaded state, and inductor-loaded state.

[0031] Step 2.3: When the port is in a capacitor-loaded state, introduce a capacitance value C. i As a port parameter variable; when the port is in an inductor-loaded state, the inductance value L is introduced. i As a port parameter variable, where i = 1, 2, ..., N. The capacitance value C i and inductance value L i All of these are lumped parameters with actual physical meaning and serve as design variables in the subsequent optimization process. When a port is in an open-circuit state, its equivalent impedance is defined as high impedance, and no electrical connection element is connected to the corresponding port location, thus maintaining electrical isolation between adjacent structural units. When a port is in a short-circuit state, its equivalent impedance is defined as low impedance, and an electrical conduction path is formed at the corresponding port location, thus achieving electrical connection between adjacent structural units.

[0032] The open-circuit and short-circuit states, as discrete structural state variables of the port, together with the capacitor-loaded and inductor-loaded states, constitute a set of port parameters, which are used to establish the port parameter model of the local oscillator near-field electromagnetic field control device.

[0033] Step 3: Based on the port parameter model established in Step 2, perform three-dimensional full-wave electromagnetic simulation to obtain scattering parameters, that is, obtain the electromagnetic response characteristics of the structure under different port configurations through electromagnetic simulation calculations. Specifically:

[0034] Step 3.1: Establish a complete three-dimensional simulation model of the local oscillator near-field electromagnetic field control device in the three-dimensional full-wave electromagnetic simulation software, and introduce the N ports and their port state parameters defined in the second step into the three-dimensional simulation model.

[0035] Step 3.2: Perform electromagnetic simulation calculations on the local oscillator near-field electromagnetic field control device with N ports to obtain the scattering parameters of the local oscillator near-field electromagnetic field control device in the target frequency band. ,in f Represents frequency variables. This represents the scattering parameter matrix.

[0036] Step 4: Calculate the impedance matrix of the ports based on the scattering parameter matrix obtained in Step 3, to characterize the equivalent electromagnetic coupling characteristics of the local oscillator near-field electromagnetic field manipulation device with N ports. Specifically:

[0037] Step 4.1: Based on the scattering parameter matrix As shown in formula (1), the corresponding port impedance matrix is ​​calculated according to the parameter transformation relationship. Where Z0 is the reference impedance, and I is the identity matrix. The impedance matrix represents a local oscillator near-field electromagnetic field control device with N ports, used to characterize the equivalent electromagnetic coupling relationship between the ports.

[0038] (1)

[0039] Step 5: Calculate the near-field electromagnetic distribution based on the impedance matrix and extract characteristic parameters of the atomic interaction region to finally obtain the near-field electromagnetic distribution characteristics of the local oscillator near-field electromagnetic field control device in the target frequency band. Specifically:

[0040] Step 5.1: Based on the impedance matrix Calculate the near-field electromagnetic distribution of the local oscillator near-field electromagnetic field control device in the target frequency band, and the impedance matrix. The port voltage-current relationship is given:

[0041] (2)

[0042] in, Represents frequency f The port current vector below; Represents frequency f The port voltage vector below;

[0043] Given the port excitation V or current I, the port currents are obtained as follows:

[0044] (3)

[0045] The current at each port serves as a radiation source. According to the principle of electromagnetic field superposition, the electric field at any spatial location r is:

[0046] (4)

[0047] in, Let i be the current at the i-th port. Let N be the Green's function field distribution generated by the i-th port under unit current excitation; N represents the total number of ports; i represents the port number, i-th port.

[0048] Step 5.2: Based on the near-field electromagnetic distribution results in Step 5.1, calculate the near-field electromagnetic field characteristic parameters corresponding to the atomic interaction region. These near-field electromagnetic field characteristic parameters include: the electric field amplitude distribution within the atomic interaction region, the effective field strength, and spatial uniformity indices. Specifically:

[0049] In the electric field amplitude distribution:

[0050] electric field complex vector for:

[0051] (5)

[0052] in, , , These represent the components of the electric field in the x, y, and z directions, respectively.

[0053] The electric field amplitude is defined as:

[0054] (6)

[0055] In the sensing chamber area The spatial distribution within the field is the electric field amplitude distribution.

[0056] The effective field strength for:

[0057] (7)

[0058] in, The volume of the air chamber region; This represents the spatial region within the atomic gas chamber where atoms participate in electromagnetic interactions. Indicates the area The volume.

[0059] Among the spatial uniformity indices:

[0060] Define the mean squared error:

[0061] (8)

[0062] Define the normalized uniformity index:

[0063] (9)

[0064] in, This represents the mean square error of the electric field amplitude; Indicates the uniformity index of the normalized electric field;

[0065] Step 6: Construct a multi-objective optimization function based on the actual requirements of the superheterodyne Rydberg atom receiving system for the local oscillator near-field environment. Specifically:

[0066] Step 6.1: Based on the actual requirements of the atomic mixing process for the local oscillator near-field electromagnetic field, including a sufficiently strong local oscillator field to drive Rabi oscillations, spatial uniformity to avoid spectral broadening, and frequency stability to avoid operating point drift, a multi-objective optimization function is constructed as follows:

[0067] (10)

[0068] The constraints are:

[0069] (11)

[0070] (12)

[0071] Where D is the port state feasible domain; Denotes the first objective function; This represents the second objective function; Indicate the third objective function; Represents the optimization variable; This represents the average field strength within the atomic interaction region at that frequency; Indicates the frequency of the authentic working center; This represents the minimum field strength threshold required for mixing operation.

[0072] Step 6.2: The multi-objective optimization objectives include: electric field uniformity index within the atomic interaction region, effective field strength index, and operational stability index within the target frequency band, as detailed below:

[0073] The electric field uniformity index is:

[0074] (13)

[0075] (14)

[0076] The effective field strength index is:

[0077] (15)

[0078] (16)

[0079] The operational stability index is:

[0080] Defined as field strength fluctuation within the frequency band:

[0081] (17)

[0082] (18)

[0083] Step 7: The NSGA-III multi-objective optimization algorithm is used to iteratively optimize the port states and their parameters, obtaining a Pareto optimal solution set that includes parameter combination points. Specifically:

[0084] Step 7.1: Employ the NSGA-III multi-objective optimization algorithm based on non-dominated sorting to analyze the port states and their corresponding capacitance values ​​C. i and inductance value L i Perform iterative optimization.

[0085] Step 7.2: Through multi-generation iterative calculations, stop the evolution calculation when the preset maximum number of iterations is reached, and obtain the Pareto non-dominated solution set based on the non-dominated sorting rule.

[0086] Step 8: Based on the non-dominated solution set obtained in Step 7, select the port configuration scheme that meets the engineering design requirements to obtain the optimal port configuration scheme. Apply it to the superheterodyne Rydberg atom receiving system to obtain the optimized local oscillator near-field electromagnetic field control device.

[0087] Step 9: Arrange the optimized local oscillator near-field electromagnetic field control device in the region below the atomic gas cell to form a stable local oscillator near-field electromagnetic environment that satisfies the superheterodyne mixing condition within the atomic interaction region.

[0088] The specific working principle and innovations of this invention are as follows:

[0089] A local oscillator near-field electromagnetic field control device with periodic pixel units is directly arranged in the region below the atomic gas cell. Multiple parameterizable ports are introduced between adjacent periodic units. By coordinating the adjustment of the port states and their corresponding lumped parameters, the equivalent electromagnetic parameter distribution of the pixelated radiation structure is changed, thereby directly controlling the near-field electromagnetic distribution within the atomic interaction region. Furthermore, this invention introduces the NSGA-III multi-objective optimization algorithm based on non-dominated sorting to iteratively optimize the port states and their parameters, ensuring that the resulting local oscillator near-field electromagnetic field simultaneously meets multiple constraints within the atomic interaction region, including electric field uniformity, effective field strength, and target frequency band operational stability. Thus, this invention achieves precise and controllable adjustment of the amplitude, phase, and spatial distribution of the local oscillator near-field electromagnetic field within a compact spatial scale without relying on complex three-dimensional cavity structures or long-distance radiation conditions. Its innovation lies in combining a pixelated near-field radiation structure with multi-port lumped loading and introducing a multi-objective optimization method to solve the problems of uneven local oscillator near-field distribution and insufficient controllability in superheterodyne Rydberg atomic receiving systems at the system level.

[0090] The beneficial effects of this invention are as follows:

[0091] (1) Achieving a high degree of integration between the local oscillator near-field electromagnetic field control device and the atomic sensing unit, effectively reducing the system size and structural complexity. This invention directly integrates the local oscillator near-field electromagnetic field control device in the region below the atomic gas chamber, replacing the large and separately located local oscillator radiating unit in the traditional superheterodyne Rydberg atomic receiving system. By using near-field electromagnetic coupling to achieve local oscillator injection under close-range conditions, the dependence on large-size radiating antennas or complex three-dimensional resonant cavities is avoided, thereby significantly reducing the overall system size and structural complexity while ensuring the mixing function, and improving the miniaturization and engineering integration capabilities of the device.

[0092] (2) Direct optimization and control of the near-field electromagnetic distribution within the atomic interaction region is achieved through pixelated structure and multi-port adjustable loading. This invention introduces a parameterizable pixelated local oscillator near-field electromagnetic field control device and sets multiple ports between adjacent periodic units. By adjusting the port states and their lumped parameters, the equivalent electromagnetic parameter distribution of the radiation structure is changed. Compared with the existing technology that mainly relies on increasing the local oscillator power or increasing the radiation distance to improve the field distribution, this invention can directly optimize and control the near-field electromagnetic distribution within the atomic interaction region within a limited spatial scale, so that a local oscillator near-field electromagnetic environment with smaller amplitude variations and more uniform spatial distribution is formed inside the gas chamber, thereby improving the consistency of the Rydberg atomic system's response to weak signals. Attached Figure Description

[0093] Figure 1 This is a schematic diagram of the electromagnetic field control device proposed in this invention;

[0094] Figure 2 This is a schematic diagram of the local oscillator near-field electromagnetic field control device for a superheterodyne Rydberg atom receiving system according to the present invention.

[0095] Figure 3 This is a block diagram of the local oscillator near-field electromagnetic field control method based on multi-objective optimization of the present invention;

[0096] Figure 4 A schematic diagram illustrating the modulation of the near-field electromagnetic field uniformity of the local oscillator within the plane of action of the atomic gas cell;

[0097] Figure 5 This is a schematic diagram illustrating the distribution of non-dominated solutions during multi-objective optimization.

[0098] Figure 6 This is a schematic diagram of the electromagnetic field control device mentioned in Example 2;

[0099] Figure 7 This is a schematic diagram of the electromagnetic field control device mentioned in Example 3;

[0100] In the diagram: 1. Metal ground plane; 2. Substrate layer; 3. Metal layer; 4. Asymptote; 5. Periodic unit structure; 6. Port; 7. First laser; 8. First optical isolator; 9. First half-wave plate; 10. First polarizing beam splitter; 11. First mirror; 12. Second half-wave plate; 13. Second polarizing beam splitter; 14. Third half-wave plate; 15. First dichroic mirror; 16. Fourth half-wave plate; 17. Third polarizing beam splitter; 18. First photodetector; 19. First wavelength-locked gas cell; 20. Beam splitter; 21. Second laser; 22. Second optical isolator; 23. Fifth half-wave plate; 24 Fourth polarization beam splitter; 25 Second reflector; 26 Sixth half-wave plate; 27 Fifth polarization beam splitter; 28 Seventh half-wave plate; 29 Second dichroic mirror; 30 Third dichroic mirror; 31 Second wavelength-locked frequency chamber; 32 Fourth dichroic mirror; 33 First optical absorption terminal; 34 Second photodetector; 35 Oscilloscope; 36 Third photodetector; 37 Horn antenna; 38 Sensing chamber; 39 Local oscillator near-field electromagnetic field control device; 40 Signal source; 41 Second optical absorption terminal; 42 Through-hole structure; 43 Intermediate dielectric layer; 44 Top metal layer. Detailed Implementation

[0101] The present invention will be further described below with reference to specific implementation examples.

[0102] Example 1

[0103] Please see Figure 1This embodiment provides a local oscillator near-field electromagnetic field manipulation device, applied in a superheterodyne Rydberg atom receiving system, used to form a spatially controllable local oscillator near-field electromagnetic field within the atomic interaction region. The local oscillator near-field electromagnetic field manipulation device comprises, from bottom to top: a metal ground layer 1, a substrate layer 2, and a metal layer 3. The metal layer 3 consists of two parts: an asymptote 4 and a periodic structure. The periodic structure is composed of an array of multiple identical periodic unit structures 5, with N ports 6 arranged between adjacent periodic unit structures 5. Specifically:

[0104] The metal floor layer 1 is a continuous metal planar structure located at the bottom of the local oscillator near-field electromagnetic field control device. It is preferably made of copper or a high-conductivity metal material, and its thickness can be selected as 35 μm. It is used to shield the electromagnetic field inside the local oscillator near-field electromagnetic field control device and provide a stable electromagnetic return path for high-frequency signals, thereby suppressing back radiation and stray coupling.

[0105] The substrate layer 2 is disposed above the metal ground layer 1 and is tightly bonded to the metal ground layer 1. The substrate layer 2 is a dielectric material, such as FR4 substrate material, and its thickness can be selected from 0.5mm to 1.6mm. Its dielectric constant and thickness are used to determine the electromagnetic propagation characteristics of the local oscillator near-field electromagnetic field control device. The substrate layer 2 provides electromagnetic isolation between the metal ground layer 1 and the metal layer 3 in the vertical direction.

[0106] The metal layer 3 is disposed on the upper surface of the substrate layer 2. The metal layer 3 is a continuous conductive metal layer and is the main carrier for the propagation and control of high-frequency electromagnetic waves in the local oscillator near-field electromagnetic field control device. A copper-clad structure is preferred, with a thickness of 35 μm. In the metal layer 3, the asymptote 4 on the left and the periodic structure on the right are electrically directly connected, forming an integrated metal transmission structure; that is, the periodic structure formed by the periodic unit structure 5 and the asymptote 4 are spatially adjacent, enabling electromagnetic coupling. This allows the local oscillator signal propagating on the asymptote 4 to excite the periodic unit structure 5 to generate a local near-field response.

[0107] In this embodiment, the asymptote 4 extends along the transmission direction to guide the local oscillator signal to propagate in the local oscillator near-field electromagnetic field control device and to excite a controlled near-field electromagnetic distribution around it. The orientation, width, and positional arrangement of the asymptote 4 with the unit structure together determine the spatial distribution pattern of the local oscillator near field. Furthermore, the periodic unit structures 5 are arranged periodically along the transmission direction of the asymptote 4, and multiple periodic unit structures 5 are arranged sequentially to form a two-dimensional periodic structure.

[0108] In this embodiment, each periodic unit structure 5 is a square metal structure with a side length of 2mm to 6mm. Each of its four sides has a port interface area reserved inward, so that while maintaining structural symmetry, the periodic unit structure 5 can form a controllable electromagnetic coupling channel with adjacent periodic units.

[0109] In this embodiment, N ports 6 are provided, and the N ports 6 are respectively disposed between two adjacent periodic unit structures 5 and electrically connected to the corresponding port interface areas. The ports 6 are used to introduce lumped parameter loading elements, thereby changing the equivalent electromagnetic connection relationship between adjacent periodic unit structures 5. The lumped parameter loading elements are electrically connected to the corresponding ports 6. By loading different states on different ports 6, the overall electromagnetic response of the periodic structure can be discretely controlled.

[0110] In this embodiment, the port states of the N ports 6 include open circuit, short circuit, capacitive loading, and inductive loading. Both the capacitive and inductive loading states are implemented using lumped capacitor or lumped inductor elements with actual physical parameter values. The capacitive loading state is implemented using lumped capacitor elements, with capacitance values ​​ranging from 0.1pF to 10pF; the inductive loading state is implemented using lumped inductor elements, with inductance values ​​ranging from 1nH to 100nH. The open circuit state means that no electrical connection element is connected to the corresponding port, maintaining electrical isolation between adjacent structural units. The short circuit state means that a low-impedance electrical connection path is formed at the corresponding port, enabling electrical connection between adjacent structural units. By applying different port states to different ports 6, the equivalent capacitance, equivalent inductance, or coupling strength between the corresponding periodic unit structures 5 can be changed, thereby reconstructing the equivalent electromagnetic parameters of the periodic unit structure 5.

[0111] In this embodiment, a through-hole structure 42 may be added to the periodic structure of the metal layer 3 to expand the structural degrees of freedom of near-field electromagnetic control.

[0112] In this embodiment, multiple stacked structures can be added above the metal layer 3 to expand the working bandwidth, control dimensions, and functional implementation methods of the local oscillator near-field electromagnetic field control device while maintaining the overall structural compactness, thereby achieving composite control of multi-frequency response, field distribution shaping, or near-field characteristics. Each stacked structure includes an intermediate dielectric layer 43 and a top metal layer 44, wherein the intermediate dielectric layer 43 is a dielectric material.

[0113] Please see Figure 3 The local oscillator near-field electromagnetic field control method used in this embodiment is based on the superheterodyne Rydberg atom receiving system and the local oscillator near-field electromagnetic field control device, and specifically includes the following steps.

[0114] First step, please refer to Figure 2 A coupling system is constructed between the Rydberg atom receiving system and the local oscillator near-field electromagnetic field control device 39 to obtain a superheterodyne Rydberg atom receiving system. The local oscillator near-field electromagnetic field control device 39 is located between the horn antenna 37 and the sensing gas chamber 38 of the Rydberg atom receiving system, wherein the sensing gas chamber 38 is located above the metal layer 3 of the local oscillator near-field electromagnetic field control device, and the horn antenna 37 is located to the side. Specifically:

[0115] The Rydberg atomic receiving system includes a laser optical system, a first wavelength laser frequency locking module, a second wavelength laser frequency locking module, an atomic sensing unit, a signal radiation unit, and a signal detection and processing unit. The laser optical system includes a first laser 7 and a second laser 21, which are used to generate the first wavelength laser and the second wavelength laser, respectively.

[0116] The first wavelength laser output from the first laser 7 is split into two laser beams after passing sequentially through the first optical isolator 8, the first half-wave plate 9, and the first polarization beam splitter 10, achieving optical isolation, polarization state adjustment, and optical path distribution. The first optical isolator 8 prevents back-reflected light from entering the first laser 7, thereby improving laser output stability; the first half-wave plate 9 adjusts the polarization direction of the incident light to control the splitting ratio of the subsequent first polarization beam splitter 10. After passing through the first polarization beam splitter 10, the first wavelength laser is split into two beams.

[0117] One laser beam split from the first polarization beam splitter 10 enters the first wavelength laser frequency-locking module to construct the atomic reference signal and stabilize the frequency of the first wavelength laser. The other laser beam split from the first polarization beam splitter 10 serves as the main probe beam path, passing sequentially through the first reflector 11, the second half-wave plate 12, the second polarization beam splitter 13, the third half-wave plate 14, and the first dichroic mirror 15. At the first dichroic mirror 15, the probe beam is split into two paths: one enters the second light absorption terminal 41 to absorb excess beam light and eliminate stray interference; the other enters the sensing gas chamber 38 as the probe beam.

[0118] The beam entering the first-wavelength laser frequency-locking module passes sequentially through the fourth half-wave plate 16 and the third polarization beam splitter 17. The fourth half-wave plate 16 is used to adjust the polarization state, enabling the third polarization beam splitter 17 to split the beam according to a set ratio. After passing through the third polarization beam splitter 17, the beam is split into three paths: the first path enters the first photodetector 18, which converts the optical signal into an electrical signal to form the error signal required for the first-wavelength laser frequency locking; the second path enters the first-wavelength frequency-locking gas chamber 19 and then reaches the beam splitter 20, where it interacts with atoms to form a frequency reference; the third path is guided to the second-wavelength laser frequency-locking module to assist in achieving frequency stabilization of the second-wavelength laser. Thus, the fourth half-wave plate 16, the third polarization beam splitter 17, the first photodetector 18, the first-wavelength frequency-locking gas chamber 19, and the beam splitter 20 together constitute the first-wavelength laser frequency-locking module.

[0119] The second laser 21 outputs a second wavelength laser, which also passes sequentially through the second optical isolator 22, the fifth half-wave plate 23, and the fourth polarization beam splitter 24. The second optical isolator 22 is used to prevent feedback light from interfering with the stable output of the second laser 21; the fifth half-wave plate 23 is used to adjust the polarization direction to control the beam splitting ratio of the fourth polarization beam splitter 24. After passing through the fourth polarization beam splitter 24, the second wavelength laser is split into two paths: the first path enters the second wavelength laser frequency-locking module; the second path is reflected by the second reflector 25 and enters the main optical path of the coupling light. The light beam entering the second-wavelength laser frequency-locking module first reaches the third dichroic mirror 30, where it splits into two paths: the first path enters the second-wavelength frequency-locking gas chamber 31, interacts with atoms to form a frequency-locking reference signal, and the remaining light after passing through the second-wavelength frequency-locking gas chamber 31 is guided by the fourth dichroic mirror 32 to the first optical absorption terminal 33 for absorption; the second path is guided by the third dichroic mirror 30 to the second photodetector 34, which is used to acquire the frequency-locking signal and generate an error signal, thereby achieving frequency stabilization of the second-wavelength laser. Thus, the third dichroic mirror 30, the second-wavelength frequency-locking gas chamber 31, the fourth dichroic mirror 32, the first optical absorption terminal 33, and the second photodetector 34 together constitute the second-wavelength laser frequency-locking module.

[0120] The second-wavelength laser, reflected by the second reflector 25, sequentially passes through the sixth half-wave plate 26, the fifth polarizing beam splitter 27, the seventh half-wave plate 28, and the second dichroic mirror 29, before entering the atom sensing unit as coupling light. The atom sensing unit includes a sensing chamber 38. The coupling light and the aforementioned probe light form an anti-collinear propagation structure within the sensing chamber 38. The two laser beams act together on the Rydberg atomic system, creating an electromagnetically induced transparency effect under appropriate frequency conditions, thereby achieving a highly sensitive response to applied electromagnetic fields. The probe light, after passing through the sensing chamber 38, is guided by the second dichroic mirror 29 to the third photodetector 36, and further sent to the signal detection and processing unit for demodulation and analysis.

[0121] The signal radiation unit includes a signal source 40 and a horn antenna 37. The horn antenna 37 is electrically connected to the signal source 40 and is used to generate the electromagnetic signal to be measured. The horn antenna 37 converts the electromagnetic signal to be measured into a free-space electromagnetic wave and radiates it to the region where the sensing chamber 38 is located. Below the sensing chamber 38, a local oscillator near-field electromagnetic field control device 39 proposed in this invention is arranged. The local oscillator near-field electromagnetic field control device 39 is electrically connected to the signal source 40 and is used to receive a stable local oscillator signal and generate a spatially controllable local oscillator near-field electromagnetic field in the atomic interaction region within the sensing chamber 38. The local oscillator near-field electromagnetic field interacts with the electromagnetic signal to be measured radiated into the sensing chamber 38 by the horn antenna 37 in the Rydberg atomic system, thereby achieving superheterodyne mixing during the atomic response process. The signal detection and processing unit includes a third photodetector 36 and an oscilloscope 35, used to perform electrical signal conversion, demodulation, and analysis on the optical signal modulated by the Rydberg atomic system. The probe light signal modulated by Rydberg atoms is converted into an electrical signal by the third photodetector 36 and finally sent to the oscilloscope 35 for display, demodulation or spectrum analysis.

[0122] Step 2: The local oscillator near-field electromagnetic field control device 39 is electrically connected to the signal source in the coupling system constructed in Step 1 and is arranged below the sensing gas chamber 38. The near-field electromagnetic field it generates mixes with the signal to be measured in the atomic system. To optimize the performance of the system described in Step 1 under near-field operating conditions, the structural parameters of the local oscillator near-field electromagnetic field control device 39 are parametrically modeled and optimized. The core is to introduce multiple controllable ports into the pre-designed local oscillator near-field electromagnetic field control device 39 and to uniformly parametrically describe the electrical state and parameters of each port, providing a variable basis for subsequent electromagnetic simulation and optimization. Specifically:

[0123] Step 2.1: Introduce N ports into the local oscillator near-field electromagnetic field control device 39, where N is a positive integer. The N ports are respectively set between adjacent periodic unit structures 5 to realize the adjustable loading of the equivalent electromagnetic parameters of the structure.

[0124] Step 2.2: Parameterize the port states of N ports, including open circuit state, short circuit state, capacitor-loaded state, and inductor-loaded state.

[0125] Step 2.3: When the port is in a capacitor-loaded state, introduce a capacitance value C. i As a port parameter variable; when the port is in an inductor-loaded state, the inductance value L is introduced. i As a port parameter variable, where i = 1, 2, ..., N. The capacitance value C i and inductance value L iAll of these are lumped parameters with actual physical meaning and serve as design variables in the subsequent optimization process. When a port is in an open-circuit state, its equivalent impedance is defined as high impedance, and no electrical connection element is connected to the corresponding port location, thus maintaining electrical isolation between adjacent structural units. When a port is in a short-circuit state, its equivalent impedance is defined as low impedance, and an electrical conduction path is formed at the corresponding port location, thus achieving electrical connection between adjacent structural units.

[0126] The open-circuit state and short-circuit state are used as discrete structural state variables of the port, which together with the capacitor loading state and the inductor loading state constitute the port parameter set, used to establish the port parameter model of the local oscillator near-field electromagnetic field control device 39.

[0127] Step 3: Based on the port parameter model established in Step 2, perform three-dimensional full-wave electromagnetic simulation to obtain scattering parameters, that is, obtain the electromagnetic response characteristics of the structure under different port configurations through electromagnetic simulation calculations. Specifically:

[0128] Step 3.1: Establish a complete three-dimensional simulation model of the local oscillator near-field electromagnetic field control device 39 in the three-dimensional full-wave electromagnetic simulation software, and introduce the N ports and their port state parameters defined in the second step into the three-dimensional simulation model.

[0129] Step 3.2: Perform electromagnetic simulation calculations on the local oscillator near-field electromagnetic field control device 39 with N ports to obtain the scattering parameters of the local oscillator near-field electromagnetic field control device 39 in the target frequency band. ,in f Represents frequency variables. This represents the scattering parameter matrix.

[0130] Step 4: Calculate the impedance matrix of the ports based on the scattering parameter matrix obtained in Step 3, to characterize the equivalent electromagnetic coupling characteristics of the local oscillator near-field electromagnetic field manipulation device 39 with N ports. Specifically:

[0131] Step 4.1: Based on the scattering parameter matrix As shown in formula (1), the corresponding port impedance matrix is ​​calculated according to the parameter transformation relationship. Where Z0 is the reference impedance, and I is the identity matrix. The impedance matrix represents a local oscillator near-field electromagnetic field control device with N ports, used to characterize the equivalent electromagnetic coupling relationship between the ports.

[0132] (1)

[0133] Step 5: Calculate the near-field electromagnetic distribution based on the impedance matrix and extract characteristic parameters of the atomic interaction region to finally obtain the near-field electromagnetic distribution characteristics of the local oscillator near-field electromagnetic field control device in the target frequency band. Specifically:

[0134] Step 5.1: Based on the impedance matrix Calculate the near-field electromagnetic distribution of the local oscillator near-field electromagnetic field control device 39 in the target frequency band, and the impedance matrix. The port voltage-current relationship is given:

[0135] (2)

[0136] in, Represents frequency f The port current vector below; Represents frequency f The port voltage vector below;

[0137] Given the port excitation V or current I, the port currents are obtained as follows:

[0138] (3)

[0139] The current at each port serves as a radiation source. According to the principle of electromagnetic field superposition, the electric field at any spatial location r is:

[0140] (4)

[0141] in, Let i be the current at the i-th port. Let N be the Green's function field distribution generated by the i-th port under unit current excitation; N represents the total number of ports; i represents the port number, i-th port.

[0142] Step 5.2: Based on the near-field electromagnetic distribution results in Step 5.1, calculate the near-field electromagnetic field characteristic parameters corresponding to the atomic interaction region. These near-field electromagnetic field characteristic parameters include: the electric field amplitude distribution within the atomic interaction region, the effective field strength, and spatial uniformity indices. Specifically:

[0143] In the electric field amplitude distribution:

[0144] electric field complex vector for:

[0145] (5)

[0146] in, , , These represent the components of the electric field in the x, y, and z directions, respectively.

[0147] The electric field amplitude is defined as:

[0148] (6)

[0149] This function is in the sensing chamber region. The spatial distribution within the field is the electric field amplitude distribution.

[0150] The effective field strength for:

[0151] (7)

[0152] in, The volume of the air chamber region; This represents the spatial region within the atomic gas chamber where atoms participate in electromagnetic interactions. Indicates the area The volume.

[0153] Among the spatial uniformity indices:

[0154] Define the mean squared error:

[0155] (8)

[0156] Define the normalized uniformity index:

[0157] (9)

[0158] in, This represents the mean square error of the electric field amplitude; Indicates the uniformity index of the normalized electric field;

[0159] Step 6: Construct a multi-objective optimization function based on the actual requirements of the superheterodyne Rydberg atom receiving system for the local oscillator near-field environment. Specifically:

[0160] Step 6.1: Based on the actual requirements of the atomic mixing process for the local oscillator near-field electromagnetic field, including a sufficiently strong local oscillator field to drive Rabi oscillations, spatial uniformity to avoid spectral broadening, and frequency stability to avoid operating point drift, a multi-objective optimization function is constructed as follows:

[0161] (10)

[0162] The constraints are:

[0163] (11)

[0164] (12)

[0165] Where D is the port state feasible domain; Denotes the first objective function; This represents the second objective function. Indicate the third objective function; Represents the optimization variable; This represents the average field strength within the atomic interaction region at that frequency; Indicates the frequency of the authentic working center; This represents the minimum field strength threshold required for mixing operation.

[0166] Step 6.2: The multi-objective optimization objectives include: electric field uniformity index within the atomic interaction region, effective field strength index, and operational stability index within the target frequency band, as detailed below:

[0167] The electric field uniformity index is:

[0168] (13)

[0169] (14)

[0170] The effective field strength index is:

[0171] (15)

[0172] (16)

[0173] The operational stability index is:

[0174] Defined as field strength fluctuation within the frequency band:

[0175] (17)

[0176] (18)

[0177] Step 7: Iteratively optimize the port states and their parameters using the NSGA-III multi-objective optimization algorithm to obtain the Pareto optimal solution set containing parameter combination points. Please refer to [link / reference]. Figure 4 Different port states can significantly alter the near-field distribution morphology within the interaction plane of the atomic gas cell. Specifically:

[0178] Step 7.1: Employ the NSGA-III multi-objective optimization algorithm based on non-dominated sorting to analyze the port states and their corresponding capacitance values ​​C. i and inductance value L i Perform iterative optimization.

[0179] Step 7.2: Please refer to Figure 5 Through multiple generations of iterative calculations, the evolutionary calculations stop when the preset maximum number of iterations is reached, and the Pareto non-dominated solution set is obtained by filtering based on the non-dominated sorting rule.

[0180] Step 8: Based on the non-dominated solution set obtained in Step 7, select a port configuration scheme that meets the engineering design requirements to obtain the optimal port configuration scheme. Apply this scheme to the superheterodyne Rydberg atom receiving system to obtain the optimized local oscillator near-field electromagnetic field control device. Specifically:

[0181] Step 8.1: Select the optimal port configuration scheme and its corresponding structural parameters that meet the preset performance indicators from the non-dominated solution set.

[0182] Step 8.2: Apply the optimal port configuration scheme to the local oscillator near-field electromagnetic field control device in the superheterodyne Rydberg atom receiving system to obtain the optimized local oscillator near-field electromagnetic field control device.

[0183] Step 9: Apply the optimized local oscillator near-field electromagnetic field manipulation device to the atomic mixing process, specifically:

[0184] Step 9.1: Process and optimize the local oscillator near-field electromagnetic field control device.

[0185] Step 9.2: Arrange the local oscillator near-field electromagnetic field control device in the region below the atomic gas cell to form a stable local oscillator near-field electromagnetic environment that satisfies the superheterodyne mixing condition within the atomic interaction region.

[0186] Without departing from the technical concept of this invention, those skilled in the art can make equivalent substitutions or modifications to the structural form of the periodic unit according to the actual application needs. For example, using metal patches of different shapes, slotted structures, or combinations thereof can all achieve the control of the near-field electromagnetic field distribution. Their technical effects are consistent with those of this invention and should all fall within the protection scope of this invention.

[0187] Example 2

[0188] Please see Figure 6 This embodiment provides a local oscillator near-field electromagnetic field control device, which is applied to a superheterodyne Rydberg atom receiving system to form a spatially controllable local oscillator near-field electromagnetic field within the atomic interaction region.

[0189] The local oscillator near-field electromagnetic field control device described in this embodiment is the same as that in embodiment 1 in terms of overall structure. The difference is that in this embodiment, a through-hole structure 42 is further introduced between the metal layer 3 and the metal ground layer 1 to expand the structural degree of freedom of near-field electromagnetic control.

[0190] A via strip is provided in the substrate layer 2. The via strip is composed of multiple via structures 42, which are distributed along the propagation direction of the local oscillator near-field electromagnetic field modulation device or its perpendicular direction. Each via structure 42 can selectively penetrate the substrate layer 2 and electrically connect the metal layer 3 and the metal ground layer 1 to change the local electromagnetic boundary conditions of the local oscillator near-field electromagnetic field modulation device.

[0191] The local oscillator near-field electromagnetic field control method used in this embodiment is consistent with the first step of Embodiment 1. The processes from the first step to step nine are the same. The difference lies in the construction method of the port parameter model in step 2.3, as detailed below:

[0192] Step 2.3: When the port is in a capacitor-loaded state, introduce a capacitance value C. i As a port parameter variable; when the port is in an inductor-loaded state, the inductance value L is introduced. i As a port parameter variable, where i = 1, 2, ..., N. The capacitance value C i and inductance value L i All of these are lumped parameters with actual physical significance and are used as design variables in the subsequent optimization process.

[0193] When a port is in an open-circuit state, its equivalent impedance is defined as high impedance, and no electrical connection element is connected to the corresponding port position, thus maintaining electrical isolation between adjacent structural units. When a port is in a short-circuit state, its equivalent impedance is defined as low impedance, and an electrical conduction path is formed at the corresponding port position, thus enabling electrical connection between adjacent structural units.

[0194] The open-circuit state and short-circuit state are used as discrete structural state variables of the port, which together with the capacitor loading state and the inductor loading state constitute the port parameter set, used to establish the port parameter model of the local oscillator near-field electromagnetic field control device 39.

[0195] Unlike Embodiment 1, this embodiment also introduces the presence or absence of the through-hole structure 42 as an adjustable structural parameter, and uses it as one of the discrete optimization variables in the multi-objective optimization algorithm. Specifically, the state variable T of the through-hole structure 42 is defined. i Where: Ti=1 indicates that a through hole structure 42 is set at the corresponding periodic unit structure position; Ti=0 indicates that a through hole structure 42 is not set.

[0196] The state variable Ti of the through-hole structure 42, together with the state variables Si of each port and the corresponding capacitance value Ci or inductance value Li, constitute the extended structural parameter space, and are introduced into the NSGA-III multi-objective optimization algorithm to participate in the iterative optimization process.

[0197] By introducing the through-hole structure 42 and using it as an optimization variable, the ability to control the local oscillator near-field electromagnetic field within the atomic interaction region can be further improved without significantly increasing the device size, thereby improving the electric field uniformity index, effective field strength index, and operating stability index within the target frequency band.

[0198] Example 3

[0199] Please see Figure 7 This embodiment provides a local oscillator near-field electromagnetic field control device, which is applied to a superheterodyne Rydberg atom receiving system to form a spatially controllable local oscillator near-field electromagnetic field within the atomic interaction region.

[0200] The local oscillator near-field electromagnetic field control device described in this embodiment is the same as that in Embodiment 1 in terms of overall structure. The difference is that in this embodiment, the local oscillator near-field electromagnetic field control device is constructed as a multi-layer radiation structure to further expand the degree of freedom of electromagnetic control and the way functions are realized.

[0201] The local oscillator near-field electromagnetic field control device described in this embodiment includes, from bottom to top:

[0202] Metal floor layer 1, substrate layer 2, metal layer 3, intermediate dielectric layer 43, and top metal layer 44.

[0203] The metal layer 3 constitutes the main radiation and near-field control unit, which works in conjunction with the N port structures disposed thereon to control the spatial distribution of the local oscillator near-field electromagnetic field.

[0204] The top metal layer 44 is disposed above the metal layer 3 and is isolated from the metal layer 3 by the intermediate dielectric layer 43. It can serve as an additional radiation layer or a coupling control layer to participate in near-field electromagnetic field modulation. Energy exchange is achieved between the metal layer 3 and the top metal layer 44 through spatial electromagnetic coupling. The coupling strength is determined by the thickness and dielectric constant of the intermediate dielectric layer 43 and the geometry of the metal layer 3. By introducing this multi-layer radiation structure, the operating bandwidth, control dimensions, and functional implementation methods of the local oscillator near-field electromagnetic field control device can be expanded while maintaining the overall structural compactness. For example, it can achieve multi-frequency response, field distribution shaping, or composite control of near-field characteristics.

[0205] By introducing a multi-layer structure, different metal layers can each perform functions such as radiation, coupling, modulation, or compensation, thereby achieving cross-integration of multiple electromagnetic functions in the same device and improving the system's flexibility and scalability.

[0206] The above embodiments are merely illustrative of the implementation methods of the present invention, but 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 protection scope of the present invention.

Claims

1. A local oscillator near-field electromagnetic field control device, characterized in that, The local oscillator near-field electromagnetic field control device (39) comprises, from bottom to top, a metal floor layer (1), a substrate layer (2), and a metal layer (3). The metal layer (3) consists of an asymptote (4) and a periodic structure. The periodic structure is composed of an array of multiple identical periodic unit structures (5), and N ports (6) are provided between adjacent periodic unit structures (5). Specifically: The metal floor layer (1) is a continuous metal planar structure located at the bottom. The substrate layer (2) is disposed above the metal floor layer (1) and is in close contact with the metal floor layer (1). The substrate layer (2) is a dielectric material and electromagnetically isolates the metal floor layer (1) from the metal layer (3) in the vertical direction. The metal layer (3) is disposed on the upper surface of the substrate layer (2). The metal layer (3) is a continuous metal conductive layer. In the metal layer (3), the asymptote (4) on the left side and the periodic structure on the right side are electrically connected to form an integrated metal transmission structure and are electromagnetically coupled so that the local oscillator signal propagating on the asymptote (4) excites the periodic unit structure (5) to generate a local near-field response.

2. The local oscillator near-field electromagnetic field control device according to claim 1, characterized in that, The asymptote (4) extends along the transmission direction. The direction, width and position of the asymptote (4) and the unit structure together determine the spatial distribution of the local oscillator near field. The periodic unit structure (5) is arranged periodically along the transmission direction of the asymptote (4). Multiple periodic unit structures (5) are arranged in sequence to form a two-dimensional periodic structure.

3. The local oscillator near-field electromagnetic field control device according to claim 1, characterized in that, Each periodic unit structure (5) is a square metal structure with port interface areas reserved inward on its four sides, so that while maintaining structural symmetry, the periodic unit structure (5) can form a controllable electromagnetic coupling channel with adjacent periodic units.

4. The local oscillator near-field electromagnetic field control device according to claim 1, characterized in that, The port (6) is provided with N ports, which are respectively located between two adjacent periodic unit structures (5) and electrically connected to the corresponding port interface area; the lumped parameter loading element is introduced through the port (6) to change the equivalent electromagnetic connection relationship between adjacent periodic unit structures (5); The port states of the N ports (6) include open circuit state, short circuit state, capacitor loading state, and inductor loading state. By applying different port states to different ports (6), the equivalent capacitance, equivalent inductance, or coupling strength between the corresponding periodic unit structures (5) are changed respectively, thereby realizing the reconstruction of the equivalent electromagnetic parameters of the periodic unit structure (5) and finally realizing the discrete control of the overall electromagnetic response of the periodic structure.

5. The local oscillator near-field electromagnetic field control device according to claim 1, characterized in that, In the local oscillator near-field electromagnetic field control device (39): A through-hole structure (42) is added to the periodic structure of the metal layer (3) to expand the structural degree of freedom of near-field electromagnetic control; Multiple stacked structures are added above the metal layer (3). Each stacked structure includes an intermediate dielectric layer (43) and a top metal layer (44). The intermediate dielectric layer (43) is a dielectric material.

6. A method for controlling the local oscillator near-field electromagnetic field, characterized in that, The local oscillator near-field electromagnetic field modulation method is based on the Rydberg atom receiving system and the local oscillator near-field electromagnetic field modulation device according to any one of claims 1-5, and includes the following steps: The first step is to construct a coupling system between the Rydberg atom receiving system and the local oscillator near-field electromagnetic field control device (39) to obtain the superheterodyne Rydberg atom receiving system. The local oscillator near-field electromagnetic field control device (39) is arranged between the horn antenna (37) and the sensing gas chamber (38) of the Rydberg atom receiving system. The sensing gas chamber (38) is located above the metal layer (3) of the local oscillator near-field electromagnetic field control device, and the horn antenna (37) is located to the side. Step 2: The local oscillator near-field electromagnetic field control device (39) is electrically connected to the signal source in the coupling system constructed in the first step and is arranged below the sensing gas chamber (38). Multiple controllable ports are introduced in the preset local oscillator near-field electromagnetic field control device (39). The electrical state and parameters of each port are uniformly parameterized and described to establish the port parameter model of the local oscillator near-field electromagnetic field control device (39). Step 3: Based on the port parameter model, perform three-dimensional full-wave electromagnetic simulation to obtain scattering parameters, that is, obtain the electromagnetic response characteristics of the structure under different port configurations through electromagnetic simulation calculation; specifically: Step 3.1: Establish a complete three-dimensional simulation model of the local oscillator near-field electromagnetic field control device (39) in the three-dimensional full-wave electromagnetic simulation software, and introduce the N ports and their port state parameters defined in the second step into the three-dimensional simulation model; Step 3.2: Perform electromagnetic simulation calculations on the local oscillator near-field electromagnetic field control device (39) with N ports to obtain the scattering parameters of the local oscillator near-field electromagnetic field control device (39) in the target frequency band. ,in f Represents frequency variables. Represents the scattering parameter matrix; Step 4: Calculate the impedance matrix of the port based on the scattering parameter matrix obtained in Step 3, and characterize the equivalent electromagnetic coupling characteristics of the local oscillator near-field electromagnetic field control device (39) with N ports. Step 5: Calculate the near-field electromagnetic distribution based on the impedance matrix and extract the characteristic parameters of the atomic interaction region to obtain the near-field electromagnetic distribution characteristics of the local oscillator near-field electromagnetic field control device (39) in the target frequency band; Step 6: Based on the actual requirements of the superheterodyne Rydberg atom receiving system for the local oscillator near-field environment, construct a multi-objective optimization function; specifically: Step 6.1: Based on the actual requirements of the atomic mixing process for the local oscillator near-field electromagnetic field, construct a multi-objective optimization function as follows: The constraints are: Where D is the port state feasible domain; Denotes the first objective function; This represents the second objective function; Indicate the third objective function; Represents the optimization variable; This represents the average field strength within the atomic interaction region at that frequency; Indicates the frequency of the authentic working center; This represents the minimum field strength threshold required for mixing operation. Step 6.2: The multi-objective optimization objectives include: electric field uniformity index within the atomic interaction region, effective field strength index, and operational stability index within the target frequency band; Step 7: Use the NSGA-III multi-objective optimization algorithm to iteratively optimize the port state and its parameters, and solve for the Pareto optimal solution set containing parameter combination points; Step 8: Based on the non-dominated solution set obtained in Step 7, select the port configuration scheme that meets the engineering design requirements to obtain the optimal port configuration scheme, and apply it to the superheterodyne Rydberg atom receiving system to obtain the optimized local oscillator near-field electromagnetic field control device. Step 9: Arrange the optimized local oscillator near-field electromagnetic field control device in the region below the atomic gas cell to form a stable local oscillator near-field electromagnetic environment that satisfies the superheterodyne mixing condition within the atomic interaction region.

7. The local oscillator near-field electromagnetic field modulation method according to claim 6, characterized in that, In the first step, the horn antenna (37) converts the electrical signal to be measured into a free-space electromagnetic wave and radiates it to the area where the sensing chamber (38) is located. The local oscillator near-field electromagnetic field control device (39) arranged below the sensing chamber (38) is electrically connected to the signal source (40) to receive a stable local oscillator signal and generate a spatially controllable local oscillator near-field electromagnetic field in the atomic interaction region within the sensing chamber (38). The local oscillator near-field electromagnetic field interacts with the electromagnetic signal to be measured radiated into the sensing chamber (38) by the horn antenna (37) and achieves superheterodyne mixing during the atomic response process.

8. The method for controlling the near-field electromagnetic field of a local oscillator according to claim 7, characterized in that, The second step is specifically as follows: Step 2.1: Introduce N ports into the local oscillator near-field electromagnetic field control device (39), where N is a positive integer. The N ports are respectively set between adjacent periodic unit structures (5) to realize the adjustable loading of the equivalent electromagnetic parameters of the structure. Step 2.2: Parameterize the port states of N ports, including open circuit state, short circuit state, capacitor-loaded state, and inductor-loaded state; Step 2.3: When the port is in a capacitor-loaded state, introduce a capacitance value C. i As a port parameter variable; when the port is in an inductor-loaded state, the inductance value L is introduced. i As a port parameter variable, where i=1,2,…,N; when the port is in an open circuit state, the equivalent impedance of the port is defined as a high impedance state, and no electrical connection element is connected to the corresponding port position, so that the adjacent structural units are electrically isolated; when the port is in a short circuit state, the equivalent impedance of the port is defined as a low impedance state, and an electrical conduction path is formed at the corresponding port position, so that the adjacent structural units are electrically connected. The open-circuit state and short-circuit state are used as discrete structural state variables of the port, which together with the capacitor loading state and the inductor loading state constitute the port parameter set, which is used to establish the port parameter model of the local oscillator near-field electromagnetic field control device (39).

9. The local oscillator near-field electromagnetic field modulation method according to claim 8, characterized in that, In the fourth step, based on the scattering parameter matrix The corresponding port impedance matrix is ​​calculated according to the parameter transformation relationship. Where Z0 is the reference impedance, and I is the identity matrix. The impedance matrix represents a local oscillator near-field electromagnetic field control device with N ports, used to characterize the equivalent electromagnetic coupling relationship between the ports; 。 10. The method for controlling the near-field electromagnetic field of a local oscillator according to claim 9, characterized in that, The fifth step is specifically as follows: Step 5.1: Based on the impedance matrix Calculate the near-field electromagnetic distribution of the local oscillator near-field electromagnetic field control device (39) in the target frequency band; Step 5.2: Based on the near-field electromagnetic distribution results in Step 5.1, calculate the near-field electromagnetic field characteristic parameters corresponding to the atomic interaction region; The near-field electromagnetic field characteristic parameters include: the electric field amplitude distribution within the atomic interaction region, the effective field strength, and spatial uniformity indicators.

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