Light beam deflection metasurface and quantum sensor

Abstract

The invention provides a light beam deflection metasurface and a quantum sensor, the light beam deflection metasurface comprises a metasurface array, and the metasurface array comprises metasurface units; each metasurface unit comprises a substrate unit block and a copper circular ring; in any metasurface array, the outer diameters of the copper circular rings are equal, and the transmission phases of the corresponding metasurface units are changed by changing the inner diameters of the copper circular rings. According to the light beam deflection metasurface disclosed by the invention, a regulation and control effect on coupling light and detection light which are frequently used in the quantum sensor is realized, the detection light is prevented from being influenced by the coupling light when being emitted, the overall structure is simple, and the manufacturing cost of the light beam deflection metasurface is relatively low, so that the quantum sensor has relatively wide application scenes; the copper circular ring is of a symmetrical structure, so that the copper circular ring has polarization independence; for detection light and coupling light, the transmissivity of the light beam deflection metasurface is kept above 90%, and efficient transmission of required light signals is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of metasurface technology, and in particular to a beam deflecting metasurface and a quantum sensor. Background Art

[0002] In recent years, microwave field measurement technology based on Rydberg atoms has developed rapidly, bringing new technologies for the precise measurement of microwave electric fields. Quantum sensors are based on the electromagnetically induced transparency effect and Autler-Townes splitting of Rydberg atoms, which can self-calibrate and trace the microwave electric field, 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 coupled light and the detection light are transmitted in opposite directions in the atomic gas chamber. The coupled light will also have a certain impact on the detection light, and it needs to be processed in a certain way before the detection light signal can be detected. The construction process is complicated and its structure occupies space. It will also face high cost, which limits the application scenarios of quantum sensors. Summary of the invention

[0003] The main purpose of the present invention is to provide a beam deflecting metasurface to solve at least one of the technical problems in the prior art, such as the coupled light in the quantum sensor makes the detection light difficult to detect, the process constructed to realize the detection of the detection light is complex, the structure occupies space, and the cost is high.

[0004] In order to achieve the above-mentioned purpose, the present invention provides a beam deflecting metasurface, including a metasurface array, a plurality of the metasurface arrays are arranged along a first direction and a second direction perpendicular to the first direction, the metasurface array includes a metasurface unit, and a plurality of the 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 one of the metasurface arrays, the outer diameters of the copper rings are equal, and the transmission phase of the corresponding metasurface unit is changed by changing the inner diameter of the copper ring, and the transmission phase of the metasurface unit increases arithmetic increments one by one along the first direction to divide a period 2π equally.

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

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

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

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

[0009] Furthermore, adjacent copper rings do not contact each other, and the center distances between adjacent copper rings are equal.

[0010] Furthermore, in any one of the metasurface arrays, the transmission phases of the metasurface units along the first direction are π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π, respectively.

[0011] The present invention also provides a quantum sensor, comprising a detection light component, a coupling light component, a photodetector, an atomic gas chamber and the beam deflection metasurface, wherein the atomic gas chamber has a first end and a second end, the detection light emitted by the detection light component is incident from the first end and emitted from the second end, the beam deflection 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 deflection metasurface and vertically emitted toward the second end, the detection light and the coupling light are collinear in opposite directions in the atomic gas chamber, and the detection light emitted from the second end is vertically incident on the beam deflection metasurface and vertically emitted toward the photodetector.

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

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

[0014] The beam deflecting metasurface in the present invention realizes phase control for light of 452nm wavelength by changing the inner diameter of the copper ring, while the vertically incident light of 785nm wavelength can still be emitted vertically, realizing the functions of light deflection control for 452nm wavelength and efficient transmission for light of 785nm wavelength, and plays a regulating role for coupling light (usually with a wavelength of 452nm) and detection light (usually with a wavelength of 785nm) frequently used in quantum sensors. Such an effect is beneficial to avoid the detection light from being affected by the coupling light when it is emitted in the quantum sensor, and is convenient for the detection and subsequent processing of the detection light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflecting metasurface is low, so that the quantum sensor after adopting the beam deflecting metasurface has a wider range of application scenarios; because the copper ring is a symmetrical structure, it has polarization independence; in addition, for the detection light and the coupling light, as the inner diameter of the copper ring changes, the transmittance of the beam deflecting metasurface is maintained at more than 90%, ensuring the efficient transmission of the required optical signal in the quantum sensor.

[0015] The quantum sensor of the present invention adopts the above-mentioned beam deflection metasurface. The beam deflection metasurface realizes phase control for light of 452nm wavelength by changing the inner diameter of the copper ring, while the vertically incident light of 785nm wavelength can still be emitted vertically, realizing the functions of light deflection control for 452nm wavelength and efficient transmission for light of 785nm wavelength, and plays a regulating role for coupling light (usually with a wavelength of 452nm) and detection light (usually with a wavelength of 785nm) often used in quantum sensors. Such an effect is beneficial to avoid the detection light from being affected by the coupling light when it is emitted in the quantum sensor, and is convenient for the detection and subsequent processing of the detection light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflection metasurface is low, so that the quantum sensor after adopting the beam deflection metasurface has a wider range of application scenarios; because the copper ring is a symmetrical structure, it has polarization independence; in addition, for the detection light and the coupling light, as the inner diameter of the copper ring changes, the transmittance of the beam deflection metasurface is maintained at more than 90%, ensuring the efficient transmission of the required optical signal in the quantum sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

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

[0018] Figure 2 A schematic diagram of the structure of a metasurface display provided by an embodiment of the present invention;

[0019] Figure 3 A schematic diagram of the structure of a beam deflecting metasurface provided in an embodiment of the present invention;

[0020] Figure 4 A corresponding relationship diagram 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 corresponding relationship diagram between the inner diameter of a copper ring and the transmittance provided in an embodiment of the present invention;

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

[0023] Figure 7 A schematic diagram of a wavefront of vertically incident detection light with a wavelength of 785 nm provided in an embodiment of the present invention;

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

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

[0026] 1. beam deflecting metasurface; 11. metasurface array; 111. metasurface unit; 1111. substrate unit block; 1112. copper ring; 2. detection light component; 3. coupling light component; 4. photodetector; 5. atomic gas chamber; 51. first end; 52. second end. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0029] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0030] Metasurface is an artificial material composed of a two-dimensional periodic subwavelength structure, which has a highly flexible electromagnetic wave control capability. Through a properly designed metasurface structure, the phase, polarization, and polarization state of the incident light can be controlled.

[0031] An embodiment of the present invention provides a beam deflecting metasurface 1, comprising a metasurface array 11, wherein a plurality of the metasurface arrays 11 are arranged along a first direction and a second direction perpendicular to the first direction, wherein the metasurface array 11 comprises a metasurface unit 111, wherein a plurality of the metasurface units 111 are arranged along the first direction; wherein the metasurface unit 111 comprises a substrate unit block 1111 and a copper ring 1112 etched on the substrate unit block 1111; wherein in any one of the metasurface arrays 11, the outer diameters of the copper rings 1112 are all equal, and the transmission phase of the corresponding metasurface unit 111 is changed by changing the inner diameter of the copper ring 1112, and the transmission phase of the metasurface unit 111 increases arithmetically one by one along the first direction to divide a period 2π equally.

[0032] Combination Figure 1 As shown in the figure, the ZXY three-axis coordinate system is used to assist in describing the orientation. The metasurface unit 111 is composed 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 side of the Z axis. The outer circle and the inner circle of the copper ring 1112 are concentric. Figure 1 and Figure 2 As shown, a plurality of metasurface units 111 are arranged along a first direction (in this embodiment, the positive X direction) to form a metasurface array 11. For example, for a plurality of copper rings 1112 in a metasurface array 11, the outer diameters of the copper rings 1112 are all equal, and the inner diameters of the copper rings 1112 are not equal. The transmission phase of each metasurface unit 111 is related to the inner diameter of its copper ring 1112. In this way, the transmission phases between these metasurface units 111 are also not equal. The phases are arithmetic-increased one by one along the first direction (the positive X direction in this embodiment) to equally divide a period 2π. For example, when the phase interval is π / 6, the transmission phases of the metasurface units 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), wherein the inner diameter of the copper ring 1112 can be referred to Figure 4 The design is based on the relationship between the inner diameter of the copper ring 1112 and the transmission phase shown in FIG. Figures 1 to 3 As shown, a plurality of 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), thereby forming a beam deflecting metasurface 1.

[0033] The beam deflecting metasurface 1 of the present invention is combined with Figure 4As shown, by changing the inner diameter of the copper ring 1112, phase control is achieved for light with a wavelength of 452nm, while light with a wavelength of 785nm incident vertically can still be emitted vertically, thereby achieving the functions of light deflection control for a wavelength of 452nm and efficient transmission for light with a wavelength of 785nm, and playing a regulating role for the coupling light (usually with a wavelength of 452nm) and the detection light (usually with a wavelength of 785nm) frequently used in quantum sensors. Such an effect is beneficial to avoiding the detection light from being affected by the coupling light when it is emitted in the quantum sensor, and is convenient for the detection and subsequent processing of the detection light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflection metasurface 1 is low, so that the quantum sensor after adopting the beam deflection metasurface 1 has a wider range of application scenarios; since the copper ring 1112 is a symmetrical structure, it has polarization independence, that is, for incident light polarized in any direction on the XY plane, vertical incidence and vertical emission of the detection light, as well as deflected incidence and vertical emission of the coupling light can be achieved; in addition, combined with Figure 5 As shown in the relationship diagram between the inner diameter of the copper ring 1112 and the transmittance, it can be seen that for the detection light and the coupled light, as the inner diameter of the copper ring 1112 changes, the transmittance of the beam deflection metasurface 1 remains above 90%, ensuring the efficient transmission of the optical signal required in the quantum sensor.

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

[0035] In this way, the use of epoxy resin material has the advantages of simple processing and low loss, which is especially suitable for quantum sensors to ensure efficient transmission of required optical signals.

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

[0037] In this embodiment, the refractive index of the copper ring 1112 is 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, so as to calculate the deflection angle of the incident light, which is particularly suitable for quantum sensors to ensure efficient transmission of the required optical signals.

[0038] Furthermore, adjacent substrate unit blocks 1111 are integrally connected.

[0039] Combination Figure 3 As shown, in actual applications, the substrate unit blocks 1111 of multiple metasurface units 111 are connected integrally between adjacent ones to form a whole substrate plate, so that each metasurface unit 111 is relatively fixed to ensure 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 distances between adjacent copper rings 1112 are equal.

[0041] Combination Figure 3 As shown, the copper rings 1112 of the multiple super surface units 111 are not in contact with each other, and the center distances between adjacent copper rings 1112 are equal, so that the inner diameters of the copper rings 1112 can be arranged according to the corresponding period.

[0042] In one of the embodiments, in any one of the metasurface arrays 11, the transmission phases of the metasurface units 111 along the first direction are π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π, respectively.

[0043] Specifically, combined Figure 1 and Figure 2 As shown, in one of the metasurface arrays 11, there are 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, according to 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 in the first direction are π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π in sequence (i.e., the inner diameter along the first direction increases as the transmission phase increases). The beam deflection metasurface 1 thus formed has a deflection control function. Figure 6 As shown, when polarized light with a wavelength of 452nm is incident on the beam deflection metasurface 1 at an angle of about 12°, it will be transmitted at a vertical angle; combined with Figure 7 As shown, when polarized light with a wavelength of 785 nm is vertically incident on the beam deflecting metasurface 1, it will be directly transmitted while maintaining a vertical angle.

[0044] The present invention also provides a quantum sensor, comprising a detection light component 2, a coupling light component 3, a photodetector 4, an atomic gas chamber 5 and the beam deflection metasurface 1, wherein the atomic gas chamber 5 has a first end 51 and a second end 52, the detection light emitted by the detection light component 2 is incident from the first end 51 and emitted from the second end 52, the beam deflection 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 deflection metasurface 1 and vertically emitted toward the second end 52, the detection light and the coupling light are collinear in opposite directions in the atomic gas chamber 5, and the detection light emitted from the second end 52 is vertically incident on the beam deflection metasurface 1 and vertically emitted toward the photodetector 4.

[0045] Combination Figure 8As shown, the atomic gas chamber 5 can be regarded as a cylindrical tubular structure, the detection light component 2 emits detection light, and the coupling light component 3 emits coupling light. In this embodiment, the wavelength of the coupling light is 452nm, and the wavelength of the detection light is 785nm. The detection light is incident on the atomic gas chamber 5 from the first end 51, and the coupling light is incident on the atomic gas chamber 5 from the second end 52. The signal to be measured and the local oscillator signal are both radiated into the atomic gas chamber 5. The detection light is emitted from the second end 52, and the emitted detection light is detected by the photodetector 4, 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 coupled light is deflected and incident on the beam deflecting metasurface 1, and then vertically emitted to the second end 52, and the detection light emitted from the second end 52 is vertically incident on the beam deflecting metasurface 1, and then vertically emitted to the photodetector 4, thereby avoiding the influence of the coupled light on the detection light and reducing the occupied space to a certain extent. The production cost of the beam deflecting metasurface 1 is relatively low, the overall structure is relatively simple, and it is easy to implement, which expands the application scenarios of quantum sensors.

[0046] The quantum sensor of the present invention adopts the above-mentioned beam deflection metasurface 1, combined with Figure 4 As shown, by changing the inner diameter of the copper ring 1112, phase control is achieved for light with a wavelength of 452nm, while light with a wavelength of 785nm incident vertically can still be emitted vertically, thereby achieving the functions of light deflection control for a wavelength of 452nm and efficient transmission for light with a wavelength of 785nm, and playing a regulating role for the coupling light (usually with a wavelength of 452nm) and the detection light (usually with a wavelength of 785nm) frequently used in quantum sensors. Such an effect is beneficial to avoiding the detection light from being affected by the coupling light when it is emitted in the quantum sensor, and is convenient for the detection and subsequent processing of the detection light signal in the quantum sensor. The overall structure is simple, and the cost of the beam deflection metasurface 1 is low, so that the quantum sensor after adopting the beam deflection metasurface 1 has a wider range of application scenarios; since the copper ring 1112 is a symmetrical structure, it has polarization independence, that is, for incident light polarized in any direction on the XY plane, vertical incidence and vertical emission of the detection light, as well as deflected incidence and vertical emission of the coupling light can be achieved; in addition, combined with Figure 5 As shown in the relationship diagram between the inner diameter of the copper ring 1112 and the transmittance, it can be seen that for the detection light and the coupled light, as the inner diameter of the copper ring 1112 changes, the transmittance of the beam deflection metasurface 1 remains above 90%, ensuring the efficient transmission of the optical signal required in the quantum sensor.

[0047] Preferably, the beam deflecting metasurface 1 is arranged on the outer wall of the second end 52. This scheme is not shown in the figure, the substrate unit blocks 1111 of the beam deflecting metasurface 1 are integrally connected to form a whole substrate plate, and the substrate plate can be arranged on the outer wall of the second end 52 by any means such as bonding, clamping, bolting, etc., so that the coupling light deflected from the second end 52 and incident to the atomic gas chamber 5 is converted into vertical emission, and the detection light vertically transmitted to the second end 52 is still vertically emitted when it is emitted from the second end 52, which can further reduce the occupied space.

[0048] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

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

[0050] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A beam deflecting metasurface, characterized in that: It comprises a metasurface array, a plurality of the metasurface arrays are arranged along a first direction and a second direction perpendicular to the first direction, the metasurface array comprises a metasurface unit, and a plurality of the metasurface units are arranged along the first direction; The metasurface unit comprises 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. The transmission phase of the corresponding metasurface unit is changed by changing the inner diameter of the copper ring. The transmission phase of the metasurface unit increases arithmetic steps along the first direction to divide a period 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 0.98-1.

1.

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

17.

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

6. The beam deflecting metasurface according to claim 1, characterized in that: Adjacent copper rings do not contact each other, and the center distances between adjacent copper rings are equal.

7. The beam deflecting metasurface according to claim 1, characterized in that: In any of the metasurface arrays, the transmission phases of the metasurface units along the first direction are π / 4, π / 2, 3π / 4, π, 5π / 4, 3π / 2, 7π / 4, and 2π, respectively.

8. A quantum sensor, characterized in that: It comprises a detection light component, a coupling light component, a photodetector, an atomic gas chamber and the beam deflecting metasurface according to any one of claims 1 to 7, wherein the atomic gas chamber has a first end and a second end, the detection light emitted by the detection light component is incident from the first end and emitted 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 vertically emitted toward the second end, the detection light and the coupling light are collinear in opposite directions in the atomic gas chamber, and the detection light emitted from the second end is vertically incident on the beam deflecting metasurface and vertically emitted 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 detection light is 785 nm.

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

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