Optical beam deflection metasurface and quantum sensor

Abstract

This invention provides a beam-deflecting metasurface and a quantum sensor. The beam-deflecting metasurface includes a metasurface array, which in turn includes metasurface units. Each metasurface unit comprises a substrate unit block and a copper ring. In any metasurface array, the outer diameter of the copper ring is uniform. By changing the inner diameter of the copper ring, the transmission phase of the corresponding metasurface unit is altered. The beam-deflecting metasurface of this invention effectively controls the coupling and probe beams frequently used in quantum sensors, preventing the probe beam from being affected by the coupling beam. The overall structure is simple, and the cost of the beam-deflecting metasurface is low, enabling the quantum sensor to have a wide range of applications. Because the copper ring has a symmetrical structure, it is polarization-independent. For both the probe and coupling beams, the transmittance of the beam-deflecting metasurface remains above 90%, ensuring efficient transmission of the required optical signals.

Description

Technical Field

[0001] This invention relates to the field of metasurface technology, and more specifically, to a beam deflecting metasurface and a quantum sensor. Background Technology

[0002] In recent years, microwave field measurement technology based on Rydberg atoms has developed rapidly, bringing new technologies to the precise measurement of microwave electric fields. Quantum sensors, based on the electromagnetic induction transparency effect and Autler-Townes splitting of Rydberg atoms, can perform self-calibrated and traceable measurements of microwave electric fields, and can cover an ultra-wide frequency range. However, traditional quantum sensors require multiple discrete optoelectronic devices to excite the optical path, and it is necessary to ensure that the coupling light and the probe light are transmitted in opposite directions in the atomic gas cell. The coupling light also has a certain influence on the probe light, which requires certain processing before the probe light signal can be detected. The construction process is complex and the structure occupies a lot of space, which also leads to high costs, thus limiting the application scenarios of quantum sensors. Summary of the Invention

[0003] The main objective of this invention is to provide a beam deflection metasurface to solve at least one of the technical problems in existing quantum sensors, such as the coupling light in the quantum sensor making it difficult to detect the probe light, the complex process required to achieve probe light detection, the large space required for the structure, and the high cost.

[0004] To achieve the above objectives, the present invention provides a beam deflecting metasurface, comprising a metasurface array, wherein a plurality of the metasurface arrays are arranged along a first direction and a second direction perpendicular to the first direction, the metasurface array comprising metasurface units, and a plurality of the metasurface units being arranged along the first direction; each metasurface unit comprising a substrate unit block and a copper ring etched on the substrate unit block; in any of the metasurface arrays, the outer diameter of the copper rings is equal, and the transmission phase of the corresponding metasurface unit is changed by changing the inner diameter of the copper rings, wherein the transmission phase of the metasurface units increases arithmetically along the first direction to divide a period of 2π equally.

[0005] Furthermore, the substrate unit block is made of epoxy resin.

[0006] Furthermore, the refractive index of the copper ring is 0.98 to 1.1.

[0007] Furthermore, the refractive index of the substrate unit block is 2.01 to 2.17.

[0008] Furthermore, the adjacent substrate unit blocks are integrally connected.

[0009] Furthermore, adjacent copper rings do not contact each other, and the center-to-center distance between adjacent copper rings is equal.

[0010] Furthermore, in any of the metasurface arrays, the transmission phase of the metasurface unit along the first direction is sequentially π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, 2π.

[0011] The present invention also provides a quantum sensor, including a probe light component, a coupling light component, a photodetector, an atomic gas cell, and the aforementioned beam deflecting metasurface. The atomic gas cell has a first end and a second end. The probe light emitted by the probe light component is incident from the first end and exits from the second end. The beam deflecting metasurface is located between the second end and the photodetector. The coupling light emitted by the coupling light component is deflected and incident on the beam deflecting metasurface and exits perpendicularly toward the second end. The probe light and the coupling light are collinear and anti-linear in the atomic gas cell. The probe light exiting from the second end is incident perpendicularly on the beam deflecting metasurface and exits perpendicularly toward the photodetector.

[0012] Furthermore, the wavelength of the coupling light is 452 nm, and the wavelength of the probe light is 785 nm.

[0013] Furthermore, the beam deflecting metasurface is disposed on the outer wall of the second end.

[0014] The beam-deflecting metasurface in this invention achieves phase modulation of 452nm wavelength light by changing the inner diameter of a copper ring, while allowing perpendicularly incident 785nm wavelength light to still exit perpendicularly. This achieves the functions of deflecting and controlling 452nm wavelength light and efficiently transmitting 785nm wavelength light. It plays a modulating role in the coupling light (typically 452nm wavelength) and probe light (typically 785nm wavelength) frequently used in quantum sensors. This effect helps to avoid the influence of coupling light on the probe light when it exits the quantum sensor, facilitating the detection and subsequent processing of the probe light signal in the quantum sensor. The overall structure is simple, and the cost of the beam-deflecting metasurface is low, making quantum sensors using the beam-deflecting metasurface have a wide range of applications. Since the copper ring has a symmetrical structure, it is polarization independent. In addition, for both probe light and coupling light, the transmittance of the beam-deflecting metasurface remains above 90% as the inner diameter of the copper ring changes, ensuring efficient transmission of the optical signals required in the quantum sensor.

[0015] The quantum sensor of this invention employs the aforementioned beam-deflecting metasurface. This metasurface achieves phase modulation of 452nm wavelength light by changing the inner diameter of the copper ring, while allowing perpendicularly incident 785nm wavelength light to still exit perpendicularly. This achieves both deflection modulation of 452nm wavelength light and efficient transmission of 785nm wavelength light. It effectively modulates the coupling light (typically 452nm wavelength) and probe light (typically 785nm wavelength) frequently used in quantum sensors. This effect helps prevent the probe light from being affected by the coupling light during emission, facilitating the detection and subsequent processing of the probe light signal. The overall structure is simple, and the cost of the beam-deflecting metasurface is low, making the quantum sensor with this metasurface suitable for a wide range of applications. Because the copper ring has a symmetrical structure, it is polarization-independent. Furthermore, for both probe and coupling light, the transmittance of the beam-deflecting metasurface remains above 90% regardless of the change in the inner diameter of the copper ring, ensuring efficient transmission of the required optical signals in the quantum sensor. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0017] Figure 1 This is a schematic diagram of the structure of a metasurface unit provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a metasurface array provided in an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the beam deflection metasurface provided in an embodiment of the present invention;

[0020] Figure 4 A diagram showing the correspondence between the inner diameter of the copper ring and the transmission phase of the metasurface unit provided in an embodiment of the present invention;

[0021] Figure 5 A diagram showing the relationship between the inner diameter of the copper ring and its transmittance, provided in an embodiment of the present invention.

[0022] Figure 6 A schematic diagram of a wavefront with a wavelength of 452 nm incident at a deflection of 12°, provided for an embodiment of the present invention;

[0023] Figure 7 A schematic diagram of a wavefront with a probe beam of 785 nm wavelength incident perpendicularly, provided in an embodiment of the present invention;

[0024] Figure 8This is a schematic diagram of the structure of a quantum sensor provided in an embodiment of the present invention.

[0025] The above figures include the following reference numerals:

[0026] 1. Beam deflecting metasurface; 11. Metasurface array; 111. Metasurface unit; 1111. Substrate unit block; 1112. Copper ring; 2. Probe light assembly; 3. Coupled light assembly; 4. Photodetector; 5. Atomic gas cell; 51. First end; 52. Second end. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0030] Metasurfaces are artificial materials composed of two-dimensional periodic subwavelength structures, possessing highly flexible electromagnetic wave manipulation capabilities. Through rationally designed metasurface structures, the phase, polarization, and polarization state of incident light can be controlled.

[0031] This invention provides a beam deflection metasurface 1, including a metasurface array 11. Multiple metasurface arrays 11 are arranged along a first direction and a second direction perpendicular to the first direction. Each metasurface array 11 includes metasurface units 111, which are arranged along the first direction. Each metasurface unit 111 includes a substrate unit block 1111 and a copper ring 1112 etched on the substrate unit block 1111. In any metasurface array 11, the outer diameter of the copper ring 1112 is equal. By changing the inner diameter of the copper ring 1112, the transmission phase of the corresponding metasurface unit 111 is changed. The transmission phase of each metasurface unit 111 increases arithmetically along the first direction to divide a period of 2π equally.

[0032] Combination Figure 1 As shown in the figure, the ZXY three-axis coordinate system is used to help describe the orientation. The metasurface unit 111 consists of a block-shaped substrate unit block 1111 and a copper ring 1112. The copper ring 1112 is etched on the surface of the substrate unit block 1111 along the positive Z-axis. The outer and inner rings of the copper ring 1112 are concentric. Figure 1 and Figure 2 As shown, multiple metasurface units 111 are arranged along a first direction (positive X direction in this embodiment) to form a metasurface array 11. Exemplarily, for multiple copper rings 1112 in a metasurface array 11, the outer diameters of the copper rings 1112 are all equal, while the inner diameters of the copper rings 1112 are all unequal. The transmission phase of each metasurface unit 111 is related to the inner diameter of its copper ring 1112. Thus, the transmission phases among these metasurface units 111 are also unequal. The phases of the metasurface units 111 along the first direction (positive X direction in this embodiment) increase arithmetically to divide a period of 2π equally. For example, when the phase interval is π / 6, the transmission phases of each metasurface unit 111 along the first direction are π / 6, π / 3, π / 2, 2π / 3, 5π / 6, π, 7π / 6, 4π / 3, 3π / 2, 5π / 3, 11π / 6, and 2π (i.e., twelve metasurface units 111 form a metasurface array). The inner diameter of the copper ring 1112 can be referenced. Figure 4 The design is based on the relationship between the inner diameter of the copper ring 1112 and the transmission phase shown in the diagram; combined with... Figures 1 to 3 As shown, multiple metasurface arrays 11 are arranged along a first direction and a second direction perpendicular to the first direction (i.e., along the positive X direction and the positive Y direction in this embodiment) to form a beam deflecting metasurface 1.

[0033] The beam deflecting metasurface 1 in this invention, combined with Figure 4As shown, phase modulation of 452nm wavelength light is achieved by changing the inner diameter of the copper ring 1112, while 785nm wavelength light incident perpendicularly can still exit perpendicularly. This achieves the functions of deflection modulation of 452nm wavelength light and efficient transmission of 785nm wavelength light. It plays a modulating role in the coupling light (usually 452nm wavelength) and probe light (usually 785nm wavelength) frequently used in quantum sensors. This effect helps to avoid the influence of coupling light on the probe light when it exits the quantum sensor, facilitating the detection and subsequent processing of the probe light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflection metasurface 1 is low, making the quantum sensor using the beam deflection metasurface 1 have a wide range of applications. Since the copper ring 1112 has a symmetrical structure, it is polarization independent, that is, for incident light polarized in any direction in the XY plane, perpendicular incident and perpendicular exit of the probe light, as well as deflected incident and perpendicular exit of the coupling light can be achieved. In addition, combined with Figure 5 The graph showing the relationship between the inner diameter of the copper ring 1112 and its transmittance shows that, for both the probe light and the coupling light, the transmittance of the beam deflection metasurface 1 remains above 90% as the inner diameter of the copper ring 1112 changes, ensuring efficient transmission of the optical signals required in the quantum sensor.

[0034] Preferably, the substrate unit block 1111 is made of epoxy resin.

[0035] Thus, using epoxy resin has the advantages of simple processing and low loss, making it particularly suitable for quantum sensors to ensure efficient transmission of the required optical signals.

[0036] Preferably, the refractive index of the copper ring 1112 is 0.98 to 1.1; and the refractive index of the substrate unit block 1111 is 2.01 to 2.17.

[0037] In this embodiment, the copper ring 1112 has a refractive index of 1.04, and the substrate unit block 1111 is made of epoxy resin with a refractive index of 2.09. According to the generalized Snell's law, the working wavelength and the phase interval between adjacent metasurface units 111 are determined, thereby calculating the deflection angle of the incident light. This is especially suitable for quantum sensors to ensure efficient transmission of the required optical signal.

[0038] Furthermore, the substrate unit blocks 1111 are integrally connected to each other.

[0039] Combination Figure 3 As shown, in practical applications, the substrate unit blocks 1111 of multiple metasurface units 111 are integrally connected to each other to form a whole substrate plate, so that each metasurface unit 111 is relatively fixed, ensuring that the beam deflection metasurface 1 can normally realize the deflection control function.

[0040] Furthermore, adjacent copper rings 1112 do not contact each other, and the center-to-center distance between adjacent copper rings 1112 is equal.

[0041] Combination Figure 3 As shown, the copper rings 1112 of the multiple metasurface units 111 do not contact each other, and the center-to-center distance between adjacent copper rings 1112 is equal, so that the inner diameters of the copper rings 1112 can be arranged according to the corresponding period.

[0042] In one embodiment, in any of the metasurface arrays 11, the transmission phase of the metasurface unit 111 along the first direction is sequentially π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, 2π.

[0043] Specifically, in combination Figure 1 and Figure 2 As shown, in one of the metasurface arrays 11, there are a total of 8 metasurface units 111 arranged along the first direction, wherein the transmission phase of each metasurface unit 111 is combined with... Figure 4 As shown, based on the relationship between the inner diameter of the copper ring 1112 and the corresponding transmission phase, it can be determined that along... Figure 2 The transmission phases along the first direction are successively π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π (i.e., the inner diameter along the first direction increases with the transmission phase). The resulting beam deflection metasurface 1 has a deflection control function, combined with... Figure 6 As shown, when polarized light with a wavelength of 452 nm is deflected at an angle of approximately 12° and incident on the beam deflection metasurface 1, it will be transmitted out at a perpendicular angle; combined with Figure 7 As shown, when polarized light with a wavelength of 785nm is incident perpendicularly onto the beam deflection metasurface 1, it will be transmitted directly at a perpendicular angle.

[0044] The present invention also provides a quantum sensor, including a probe light component 2, a coupling light component 3, a photodetector 4, an atomic gas cell 5, and the aforementioned beam deflecting metasurface 1. The atomic gas cell 5 has a first end 51 and a second end 52. The probe light emitted by the probe light component 2 is incident from the first end 51 and exits from the second end 52. The beam deflecting metasurface 1 is located between the second end 52 and the photodetector 4. The coupling light emitted by the coupling light component 3 is deflected and incident on the beam deflecting metasurface 1 and exits perpendicularly toward the second end 52. The probe light and the coupling light are collinear and in opposite directions in the atomic gas cell 5. The probe light exiting from the second end 52 is incident perpendicularly on the beam deflecting metasurface 1 and exits perpendicularly toward the photodetector 4.

[0045] Combination Figure 8As shown, the atomic gas cell 5 can be considered as a cylindrical tubular structure. The probe light assembly 2 emits probe light, and the coupling light assembly 3 emits coupling light. In this embodiment, the wavelength of the coupling light is 452 nm, and the wavelength of the probe light is 785 nm. The probe light enters the atomic gas cell 5 from the first end 51, and the coupling light enters the atomic gas cell 5 from the second end 52. Both the signal to be measured and the local oscillator signal are radiated into the atomic gas cell 5. The probe light exits from the second end 52, and the photodetector 4 detects the exited probe light, thereby realizing the measurement of the signal to be measured. The coupling light component 3 can be arranged at a certain angle so that the coupling light is deflected and incident on the beam deflecting metasurface 1, and then emitted perpendicularly to the second end 52. The probe light emitted from the second end 52 is incident perpendicularly on the beam deflecting metasurface 1, and then emitted perpendicularly to the photodetector 4, thereby avoiding the influence of the coupling light on the probe light and reducing the space occupied to a certain extent. The manufacturing cost of the beam deflecting metasurface 1 is relatively low, the overall structure is relatively simple and easy to implement, and it expands the application scenarios of quantum sensors.

[0046] The quantum sensor in this invention employs the aforementioned beam-deflecting metasurface 1, combined with... Figure 4 As shown, phase modulation of 452nm wavelength light is achieved by changing the inner diameter of the copper ring 1112, while 785nm wavelength light incident perpendicularly can still exit perpendicularly. This achieves the functions of deflection modulation of 452nm wavelength light and efficient transmission of 785nm wavelength light. It plays a modulating role in the coupling light (usually 452nm wavelength) and probe light (usually 785nm wavelength) frequently used in quantum sensors. This effect helps to avoid the influence of coupling light on the probe light when it exits the quantum sensor, facilitating the detection and subsequent processing of the probe light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflection metasurface 1 is low, making the quantum sensor using the beam deflection metasurface 1 have a wide range of applications. Since the copper ring 1112 has a symmetrical structure, it is polarization independent, that is, for incident light polarized in any direction in the XY plane, perpendicular incident and perpendicular exit of the probe light, as well as deflected incident and perpendicular exit of the coupling light can be achieved. In addition, combined with Figure 5 The graph showing the relationship between the inner diameter of the copper ring 1112 and its transmittance shows that, for both the probe light and the coupling light, the transmittance of the beam deflection metasurface 1 remains above 90% as the inner diameter of the copper ring 1112 changes, ensuring efficient transmission of the optical signals required in the quantum sensor.

[0047] Preferably, the beam deflecting metasurface 1 is disposed on the outer wall of the second end 52. (Not shown in the figures of this embodiment) The substrate unit blocks 1111 of the beam deflecting metasurface 1 are integrally connected to form a single substrate plate. This substrate plate can be disposed on the outer wall of the second end 52 by any method such as bonding, snap-fitting, or bolting, so that the coupled light incident from the second end 52 to the atomic gas cell 5 is converted into vertically emitted light, while the probe light transmitted vertically to the second end 52 remains vertically emitted when it exits from the second end 52, further reducing the space occupied.

[0048] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0049] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0050] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A beam-deflecting metasurface, characterized in that, The system includes a metasurface array, wherein multiple metasurface arrays are arranged along a first direction and a second direction perpendicular to the first direction, and the metasurface array includes metasurface units, wherein multiple metasurface units are arranged along the first direction; The metasurface unit includes a substrate unit block and a copper ring etched on the substrate unit block; In any of the metasurface arrays, the outer diameters of the copper rings are all equal. By changing the inner diameter of the copper rings, the transmission phase of the corresponding metasurface unit is changed. The transmission phase of the metasurface unit increases arithmetically along the first direction to divide a period of 2π equally.

2. The beam deflecting metasurface according to claim 1, characterized in that, The substrate unit block is made of epoxy resin.

3. The beam deflecting metasurface according to claim 1, characterized in that, The refractive index of the copper ring is 0.98 to 1.

1.

4. The beam deflecting metasurface according to claim 1, characterized in that, The refractive index of the substrate unit block is 2.01 to 2.

17.

5. The beam deflecting metasurface according to claim 1, characterized in that, The substrate unit blocks are integrally connected to each other.

6. The beam deflecting metasurface according to claim 1, characterized in that, The adjacent copper rings do not contact each other, and the center-to-center distance between adjacent copper rings is equal.

7. The beam deflecting metasurface according to claim 1, characterized in that, In any of the metasurface arrays, the transmission phase of the metasurface unit along the first direction is sequentially π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, 2π.

8. A quantum sensor, characterized in that, The device includes a probe light assembly, a coupling light assembly, a photodetector, an atomic gas cell, and a beam deflecting metasurface as described in any one of claims 1 to 7. The atomic gas cell has a first end and a second end. The probe light emitted by the probe light assembly is incident from the first end and exits from the second end. The beam deflecting metasurface is located between the second end and the photodetector. The coupling light emitted by the coupling light assembly is deflected and incident on the beam deflecting metasurface and exits perpendicularly toward the second end. The probe light and the coupling light are collinear and in opposite directions in the atomic gas cell. The probe light exiting from the second end is incident perpendicularly on the beam deflecting metasurface and exits perpendicularly toward the photodetector.

9. The quantum sensor according to claim 8, characterized in that, The wavelength of the coupling light is 452 nm, and the wavelength of the probe light is 785 nm.

10. The quantum sensor according to claim 8, characterized in that, The beam deflection metasurface is disposed on the outer wall of the second end.

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