Detector and related equipment

Abstract

A detector (3000) for increasing the field angle of the detector (3000), thereby improving the sensitivity of the detector (3000). The detector (3000) comprises a non-diffractive lens (3100) and a detection unit (3200), the non-diffractive lens (3100) is used for converting an incident signal of the detector (3000) into a non-diffractive wave beam and converging the non-diffractive wave beam to a detection surface (3210) of the detection unit (3200), the detection surface (3210) of the detection unit (3200) is used for detecting the non-diffractive wave beam, and the distance d between the detection surface (3210) and the non-diffractive lens (3100) is smaller than the aperture D of the non-diffractive lens (3100).

Description

A detector and related equipment Technical Field

[0001] The embodiments of the present application relate to the field of detectors, and in particular to a detector and related equipment. Background Art

[0002] Photodetectors are used to convert light signals into electrical signals. The detection speed of a photodetector is related to the photosensitive area of ​​its photosensitive cell: smaller photosensitive areas result in faster detection speeds. To achieve higher detection speeds, the photosensitive area is typically smaller. However, a small photosensitive area can lead to lower sensitivity. Therefore, a convex lens is often used to focus the light beam onto the photosensitive cell, increasing the light intensity entering the cell and boosting the sensitivity of the detection unit.

[0003] A convex lens converges light beams onto the photosensitive cells by refracting them. However, the refractive power of a convex lens is limited, and it can only refract light beams within a certain angle range onto the photosensitive cells. This angle range is called the convex lens's field of view. Light beams outside the field of view cannot converge onto the photosensitive cells, limiting the detection angle of the light detector. As a result, the light intensity entering the photosensitive cells is low, and the detector's sensitivity is reduced.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a detector and related equipment for increasing the field of view of the detector, thereby improving the sensitivity of the detector.

[0006] In a first aspect, embodiments of the present application provide a detector comprising a non-diffraction lens and a detection unit. The non-diffraction lens is configured to convert an incident signal from the detector into a non-diffraction beam and converge the non-diffraction beam onto a detection surface of the detection unit. The detection surface of the detection unit is configured to detect the non-diffraction beam, and a distance d between the detection surface and the non-diffraction lens is less than an aperture D of the non-diffraction lens.

[0007] In an embodiment of the present application, a non-diffraction lens is used instead of an ordinary convex lens to realize the convergence of the detector input signal, and the detection surface is moved forward to between the focal plane and the non-diffraction lens. Since the focal depth of the non-diffraction lens is greater than that of the ordinary convex lens, the light beam within the field of view angle is also converged within the focal depth range in front of the focal plane. Therefore, after the detection surface is moved forward, the light beam within the field of view angle can still be projected onto the detection surface, and the light sensitivity within the field of view angle is not affected. Due to the forward movement of the detection surface, the light beam originally outside the field of view angle can also be projected onto the detection surface, and the forward movement of the detection surface increases the field of view angle. In summary, through the detector structure provided by the embodiment of the present application, the field of view angle is increased without affecting the light sensitivity within the field of view angle, so that the light intensity entering the detector is increased, which can improve the sensitivity of the detector.

[0008] In an optional implementation, the phase increment of the incident signal by the non-diffractive lens is Where x is the distance between the incident point of the incident signal on the non-diffractive lens and the optical axis of the non-diffractive lens, is a monotonic function or a constant.

[0009] In the embodiments of the present application, the phase gradient is a monotonic function or a constant, and the phase gradient changes in the non-diffraction lens in the same direction (consistently increasing or decreasing). This same trend allows the focal depth of the non-diffraction lens to be accumulated, thereby achieving a longer focal depth. This increased focal depth allows the detection surface to be moved further forward, thereby further increasing the field of view and improving the sensitivity of the detector.

[0010] In an optional implementation, the non-diffracting beam is a Bessel beam, Wherein M is a constant greater than 0.

[0011] In the embodiments of this application, the Bessel beam is widely used in the industry, and the corresponding non-diffraction lens structure is relatively mature, making it easy to obtain. Therefore, setting the non-diffraction beam as a Bessel beam or an Airy beam can reduce the processing and manufacturing costs of the non-diffraction lens and even the entire detector.

[0012] In an optional implementation, the non-diffracting beam is an Airy beam, Wherein M is a constant greater than 0.

[0013] In the embodiments of this application, the Airy beam is a widely used beam in the industry, and the corresponding non-diffraction lens structure is relatively mature, making it easy to obtain. Therefore, setting the non-diffraction beam as a Bessel beam or Airy beam can reduce the processing and manufacturing costs of the non-diffraction lens and even the entire detector.

[0014] In an optional implementation, is a monotonically decreasing function.

[0015] In the embodiment of the present application, the phase gradient The monotonically decreasing diffraction-free lens makes the diffraction-free beam concave. Compared with other beam distribution forms (such as protruding beam distribution), the concave beam quickly approaches the central axis after being emitted from the diffraction-free lens, so the beam can be focused at a position closer to the diffraction-free lens. As a result, the detection surface can be set at a position closer to the diffraction-free lens to achieve a larger field of view, thereby making the detector have a higher detection sensitivity. In addition, the concave beam distribution can achieve a smaller focal spot, thereby reducing the area of ​​the detection surface and improving the detection rate of the detector 3000.

[0016] In an optional implementation,

[0017] In an optional implementation, the phase gradient Where λ is the wavelength of the incident signal, a and b are constants, and a>b. The main lobe trajectory of the undiffracted beam corresponding to this phase gradient is an elliptical curve.

[0018] In an embodiment of the present application, the tangent line between the light beam having an elliptical curve and the optical axis is exactly on the optical axis, so the focusing performance is better, and the focusing range of the light beam is closer to the non-diffraction lens, so that the field of view angle can be larger and the sensitivity of the detector is better.

[0019] In an optional implementation, d≤0.7D.

[0020] In an optional implementation, 0.05D≤d≤0.5D.

[0021] In an optional implementation, the center point of the detection surface is outside the normal line of the non-diffractive lens.

[0022] Through the detector structure provided in the embodiment of the present application, it is possible to increase the field of view angle and ensure the photosensitivity within the field of view angle in an oblique incidence structure, thereby increasing the light intensity entering the detection surface and improving the sensitivity of the detector.

[0023] In an optional implementation, the incident signal is a light signal, the detection unit is a photosensitive unit, and the detection surface is a photosensitive surface.

[0024] In an optional implementation, the incident signal is a signal in a target band, which is in the terahertz band or the millimeter wave band. The detection surface includes a receiving antenna, which is used to detect the signal in the target band.

[0025] In an optional implementation, the non-diffraction lens includes: an axicon lens, a metasurface, a phase plate, or a grating.

[0026] In a second aspect, an embodiment of the present application provides a communication device, which includes the detector described in the first aspect.

[0027] In a third aspect, an embodiment of the present application provides a sensing device, which includes the detector described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic diagram of the structure of the detector provided in this application;

[0029] FIG2 is a schematic diagram of light beams at different positions on the detection surface of the detector provided by the present application;

[0030] FIG3 is a schematic structural diagram of a detector provided in an embodiment of the present application;

[0031] FIG4 is a schematic diagram of the focusing range of a common convex lens provided in this application;

[0032] FIG5 is a schematic diagram of the focusing range of a non-diffraction lens provided in an embodiment of the present application;

[0033] FIG6 is a schematic diagram of a light beam of a detector provided in an embodiment of the present application;

[0034] FIG7 is a schematic diagram of a light beam with a monotonically decreasing phase gradient in a detector without a diffraction lens provided in an embodiment of the present application;

[0035] FIG8 is a schematic diagram of a light beam with a monotonically increasing phase gradient in a detector without a diffraction lens provided in an embodiment of the present application;

[0036] FIG9 is a schematic diagram of a light beam having an elliptical curve in a detector provided by an embodiment of the present application;

[0037] FIG10 is a schematic diagram of light beam changes according to an embodiment of the present application;

[0038] FIG11 is a schematic diagram of determining the phase of each point of a non-diffraction lens using defocus theory according to an embodiment of the present application;

[0039] FIG12 is a schematic diagram of the structure of the oblique incidence of the light beam in the detector provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described below with reference to the accompanying drawings.

[0041] The terms "first," "second," and the like in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that the terms used in this manner are interchangeable where appropriate, and this is merely a way of distinguishing objects of the same attributes when describing the embodiments of this application. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, so that a process, method, system, product, or device comprising a series of units need not be limited to those units, but may include other units that are not clearly listed or inherent to these processes, methods, products, or devices. In addition, "at least one" refers to one or more, and "a plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can represent: A exists alone, A and B exists simultaneously, or B exists alone. Wherein A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc.

[0042] Detectors are widely used in sensing, detection, communications, energy, and other fields. They receive electromagnetic wave signals and convert them into electrical signals. These electromagnetic wave signals can optionally include optical signals such as infrared, visible, and ultraviolet light, or other electromagnetic wave forms such as radio waves, though this application does not limit these.

[0043] In some scenarios (such as LiDAR and wireless optical communications), detectors require a high detection rate. As shown in Figure 1, a detector includes a detection unit with a detection surface that converts electromagnetic wave signals into electrical signals. The detection speed of a detector depends primarily on the size of the detection surface; the smaller the detection surface, the faster the detection speed. To achieve a high detection speed, the detection surface is typically smaller.

[0044] However, the small area of ​​the detection surface leads to low light intensity entering the detection surface, which in turn leads to low sensitivity of the detector. In order to improve the sensitivity of the detector, a convex lens is set in the detector. As shown in Figure 1, the convex lens converges the light beam to the detection surface, thereby increasing the light intensity entering the detection surface and thus improving the sensitivity of the detector. For example, if the detection area of ​​the detection surface is less than 1mm 2 , the convex lens can be 2cm 2 The light beam within the range converges onto the detection surface, greatly enhancing the light intensity entering the detection surface.

[0045] A convex lens converges the light beam onto the detection surface by refracting it. However, the refractive effect of a convex lens is limited, and it can only refract light beams within a certain angle range onto the detection surface. This angle range is called the field of view of the convex lens. As shown in Figure 1, the solid line represents the light beam within the field of view, and the dotted line represents the light beam outside the field of view. Light beams outside the field of view cannot converge onto the detection surface and cannot be received by the detection surface. Therefore, the detection angle of the detector is limited, resulting in a limited light intensity entering the photosensitive unit and low sensitivity of the detector.

[0046] In order to achieve an improvement in sensitivity, one idea of ​​the embodiments of the present application is to increase the field of view, and the specific implementation is to move the detection surface forward (to a position closer to the convex lens). For example, as shown in Figure 2, beams 1, 2, 3, and 4 are beams within the field of view, and beam 5 is a beam outside the field of view. As shown in Figure 2a, if the detection surface is on the focal plane, beams 1 to 4 can all be projected onto the detection surface, but beam 5 cannot be projected onto the detection surface.

[0047] As shown in Figure 2b, if the detection surface is moved forward to a position in front of the focal plane and closer to the convex lens, light beam 5 originally outside the field of view can be projected onto the detection surface, thereby increasing the field of view. However, light beams 1 to 4 originally within the field of view cannot be projected onto the detection surface, resulting in a decrease in the light sensitivity within the field of view. This decrease in light sensitivity within the field of view will result in a loss of light intensity entering the detection surface. Therefore, based on the current detector structure, the solution of moving the detection surface forward to increase the field of view does not necessarily increase the light intensity entering the detection surface, nor does it necessarily improve the sensitivity of the detector.

[0048] To solve the above problems, the present invention provides a detector that uses a non-diffraction lens to converge electromagnetic wave signals, thereby increasing the field of view while ensuring the light intensity within the field of view, thereby improving the sensitivity of the detector.

[0049] As shown in FIG3 , the detector 3000 provided in an embodiment of the present application includes a non-diffraction lens 3100 and a detection unit 3200 . The non-diffraction lens 3100 is used to convert the incident signal of the detector 3000 into a non-diffraction beam and converge the non-diffraction beam onto the detection surface 3210 of the detection unit 3200 .

[0050] The detection unit 3200 includes a detection surface 3210, which is used to detect the non-diffracting beam. The distance d between the detection surface 3210 and the non-diffracting lens 3100 is less than the aperture D of the non-diffracting lens. It is worth noting that in the embodiments of the present application, d refers to the distance between the edge surface of the non-diffracting lens 3100 and the detection surface. This edge surface is the surface from which the non-diffracting beam emerges from the non-diffracting lens 3100.

[0051] A major characteristic of a non-diffracting beam is its long focal depth. Focal depth refers to the depth of the focal point. In theory, a convex lens converges a beam to a single point on the focal plane, called the focus. In practice, the focus has a specific length in the direction of beam propagation. This length is the focal depth, and the beam remains focused within this depth.

[0052] For an ordinary convex lens, the focal depth δ=k*λ*f 2 / D 2 . Where k = 2.44, λ, f, and D are the wavelength of the incident beam (also called the incident wavelength), the focal length of the convex lens, and the aperture size of the convex lens, respectively. Since f / D is usually not large, the focal depth of the convex lens is very short, usually only a few to dozens of incident wavelengths. In order to achieve focusing of the beam to the detection surface, the detection surface needs to be set within the focal depth range. Therefore, as shown in Figure 4, in the detector structure that achieves focusing through an ordinary convex lens, the position of the detection surface can only fall within a smaller focal depth range, that is, near the focal plane.

[0053] For the non-diffractive lens 3100, the theoretical focal depth δ = πD 2 / λ. Where D and λ are the aperture size and incident wavelength of the non-diffractive lens 3100, respectively. The incident wavelengths of incident signals such as millimeter wave signals, infrared light signals, visible light signals, and ultraviolet light signals are all within the millimeter range (≤10mm). Within this wavelength range, the focal depth of the non-diffractive lens 3100 is δ = πD 2 / λ is much larger than the focal depth of an ordinary convex lens δ=k*λ*f 2 / D 2 Therefore, as shown in FIG5 , in the detector 3000 structure provided in the embodiment of the present application, the position of the detection surface 3210 can fall within a larger focal depth range. Compared to a detector structure including an ordinary convex lens, in the detector 3000 provided in the embodiment of the present application, the detection surface 3210 can be located closer to the lens.

[0054] In the structure shown in FIG4 , the distance between the focal plane and the convex lens is the focal length f of the convex lens, and the detection surface is near the focal plane. Generally speaking, the focal length f is greater than the aperture D of the convex lens, so the distance d between the detection surface and the convex lens is usually greater than the aperture D of the convex lens. In the detector 3000 structure provided in the embodiment of the present application, the focal depth is within a larger range near the focal plane, so the detection surface 3210 can be moved forward to a position closer to the non-diffraction lens 3100, and the distance d between the detection surface 3210 and the non-diffraction lens can be less than the aperture D of the non-diffraction lens 3100.

[0055] It is worth noting that the aperture D refers to the distance between the two farthest points on the non-diffractive lens 3100. For example, if the non-diffractive lens 3100 is a circular lens, D is the diameter of the circular lens. If the non-diffractive lens 3100 is a square lens, D is the diagonal length of the square.

[0056] As shown in Figure 6, assuming that beams 1, 2, 3, and 4 are at the edge of the field of view of the non-diffraction lens 3100, these four beams can be projected onto the detection surface 3210 of the focal plane after being converged by the non-diffraction lens 3100. In this case, the field of view is the angle between beams 1 and 2.

[0057] Because the non-diffractive lens 3100 has a long focal depth, light beams are also focused in front of the focal plane (i.e., at a position closer to the non-diffractive lens 3100 than the focal plane). Therefore, by moving the detection surface 3210 forward relative to the focal plane (to a position closer to the non-diffractive lens 3100), light beams 1 to 4 can all be projected onto the detection surface 3210.

[0058] For light beams outside the field of view (e.g., light beam 5 in Figure 6 ), on the focal plane, these beams cannot be projected onto the detection surface 3210. However, as the detection surface 3210 moves forward, it intersects with the propagation path of light beam 5, allowing light beam 5 to be projected onto the detection surface 3210. In other words, if the detection surface 3210 is moved forward relative to the focal plane, the moved focal plane 3210 can receive light beams outside the original field of view, thereby increasing the field of view of the detector 3000.

[0059] In an embodiment of the present application, the input signal of the detector 3000 is converged by replacing the ordinary convex lens with a diffraction-free lens 3100, and the detection surface 3210 is moved forward to between the focal plane and the diffraction-free lens 3100. Since the focal depth of the diffraction-free lens 3100 is greater than the focal depth of an ordinary convex lens, the light beam within the field of view angle is also converged within the focal depth range in front of the focal plane. Therefore, after the detection surface 3210 is moved forward, the light beam within the field of view angle can still be projected onto the detection surface 3210, and the light sensitivity within the field of view angle is not affected. Due to the forward movement of the detection surface 3100, the light beam originally outside the field of view angle range can also be projected onto the detection surface 3100, and the forward movement of the detection surface 3100 increases the field of view angle. In summary, through the detector 3000 structure provided in the embodiment of the present application, the field of view angle is increased without affecting the light sensitivity within the field of view angle, so that the light intensity entering the detector 3000 is increased, which can improve the sensitivity of the detector 3000.

[0060] For an ordinary convex lens, although a long focal length can also be used to achieve a relatively long depth of focus, the size of the depth of focus is still relatively limited and cannot achieve the same long depth of focus as a non-diffracting lens. Moreover, the long depth of focus of an ordinary convex lens will result in a relatively large focal spot, increasing the area of the detection surface and affecting the detection speed. The non-diffracting lens 3100 has good focusing performance while having a long depth of focus, and can obtain a relatively small focal spot within a relatively long depth of focus range. It can achieve a smaller area of the detection surface 3210, thereby improving the detection speed of the detector 3000.

[0061] In the embodiments of the present application, the non-diffracting lens 3100 can be an axicon lens, a metasurface, a phase plate, a grating, etc., and the present application does not limit this.

[0062] In the embodiments of the present application, the incident signal can be an optical signal (such as infrared light, visible light, ultraviolet light, etc.), a millimeter-wave signal, or a signal in the terahertz band, and the present application does not limit this.

[0063] If the incident signal is an optical signal, the detection unit 3200 is a photosensitive unit, and the detection surface 3210 is a photosensitive surface. In an optional implementation, if the incident signal is a millimeter-wave signal, a signal in the terahertz band, etc., the detection unit 3200 is a detection unit corresponding to the band, and the detection surface 3210 is a receiving antenna corresponding to the band.

[0064] In an optional implementation, the non-diffracting lens 3100 has a special phase characteristic. Assume that the phase increment of the non-diffracting lens 3100 for the incident signal is where x is the distance between the incident point of the incident signal on the non-diffracting lens 3100 and the optical axis of the non-diffracting lens 3100, then is a monotonic function or a constant. is also called the phase gradient.

[0065] In the embodiments of the present application, the phase gradient is a monotonic function or a constant, and the change trend of the phase gradient on the non-diffracting lens 3100 is in the same direction (always increasing or always decreasing). The same-direction change trend can achieve the accumulation of the depth-of-focus length of the non-diffracting lens 3100, thereby achieving a longer depth of focus. The lengthening of the depth of focus can achieve the further forward movement of the detection surface 3210, thereby further increasing the field of view angle and improving the sensitivity of the detector 3000.

[0066] Assume that in the detector 3000, the distance between the detection surface 3210 and the non-diffracting lens 3100 is d, and the aperture of the non-diffracting lens 3100 is D, then d < D. Optionally, it can be made that d ≤ 0.7D. Further, if the depth of focus of the non-diffracting lens 3100 is long enough (for example, the phase gradient is a monotonic function, and theoretically the depth-of-focus range can be infinitely close to the non-diffracting lens 3100), then it can be made that 0.05D ≤ d ≤ 0.5D.

[0067] Optionally, the phase gradient of the non-diffracting lens 3100 can be a strictly monotonic function. That is, if x1 < x2, then or, if x1 < x2, then

[0068] Optionally, the phase gradient of the non-diffracting lens 3100 can be a non-strictly monotonic function. That is, if x1 < x2, then or, if x1 < x2, then

[0069] In an optional implementation, the non-diffracting lens 3100 is an axicon lens, and the corresponding non-diffracting beam is a Bessel beam. In this structure, the phase function M is a constant greater than 0. The phase gradient of the non-diffracting lens 3100 in this structure The phase gradient is a constant.

[0070] In an optional implementation, the non-diffracting beam is an Airy beam. Correspondingly, the phase function of the non-diffracting lens 3100 M is a constant greater than 0. The phase gradient of the non-diffracting lens 3100 in this structure The phase gradient is a monotonic function.

[0071] Optionally, in addition to the Bessel beam, the non-diffracting beam can also be a Weber beam, a Mathieu beam, etc., and this application does not limit this.

[0072] In the embodiments of this application, the Bessel beam and the Airy beam are beams with a wide range of applications in the industry. The corresponding structural solutions of the non-diffracting lens 3100 are relatively mature, and the difficulty of obtaining the non-diffracting lens 3100 is low. Therefore, setting the non-diffracting beam as a Bessel beam or an Airy beam can reduce the manufacturing cost of the non-diffracting lens 3100 and even the entire detector 3000.

[0073] Different phase gradient settings of the non-diffracting lens 3100 will generate non-diffracting beams with different morphologies. As shown in FIG. 7 for example, if the phase gradient of the non-diffracting lens 3100 is a monotonically decreasing function, the non-diffracting beam is concave. As shown in FIG. 8 for example, if the phase gradient of the non-diffracting lens 3100 is a monotonically increasing function, the non-diffracting beam is convex.

[0074] In the example shown in FIG7 , the non-diffraction lens 3100 with a monotonically decreasing phase gradient makes the non-diffraction beam concave. Compared with other beam distribution forms (such as a protruding beam distribution), the concave beam quickly approaches the central axis after being emitted from the non-diffraction lens 3100, so that the beam can be focused at a position closer to the non-diffraction lens 3100. As a result, the detection surface 3210 can be set at a position closer to the non-diffraction lens 3100 to achieve a larger field of view, thereby making the detector 3000 have a higher detection sensitivity. In addition, the concave beam distribution can achieve a smaller focal spot, thereby reducing the area of ​​the detection surface 3210 and improving the detection rate of the detector 3000.

[0075] In an optional implementation, the phase function of the non-diffractive lens 3100 is At this time, the phase gradient is The phase gradient is a decreasing function.

[0076] In an optional implementation, the main lobe of the light beam emitted from the non-diffraction lens 3100 has an elliptical curve transmission direction. The corresponding non-diffraction lens 3100 phase gradient is Where λ is the wavelength of the incident signal, a and b are constants, and a>b.

[0077] As shown in Figure 9, in an embodiment of the present application, the tangent line between the light beam having an elliptical curve and the optical axis is just on the optical axis, and the focusing performance is better. The focusing range of the light beam is closer to the non-diffraction lens 3100, so that the field of view angle can be larger and the sensitivity of the detector 3000 is better.

[0078] In this structure, the phase gradient is also a monotonically decreasing function, and the shape of the non-diffraction lens 3100 can be designed based on this phase gradient. For example, the phase value of a point on the lens surface of the non-diffraction lens 3100 can be set first. The coordinate of this point is x, and the phase gradient is Then, set another point Δx away from this point. The coordinates of this point are x+Δx and the phase is

[0079] In the example of this application, after determining the beam curve of the non-diffracting beam, the phase function of the non-diffracting lens 3100 used to implement the beam curve can be determined. The determination method includes determining based on mathematical relationships, determining based on defocus theory, etc., which is not limited in this application.

[0080] An example of determining the phase function of the diffraction-free lens 3100 based on a mathematical relationship is a Bessel beam. Mathematically, a Bessel beam (diffraction-free beam) can be generated by a Gaussian beam (incident signal) through a circularly symmetric linear phase change, and the corresponding diffraction-free lens 3100 is an axial cone lens. For example, as shown in Figure 10, a Gaussian beam (incident signal) can be incident on an axial cone lens (diffraction-free lens 3100) to generate a Bessel beam (diffraction-free beam) through phase transformation. The side view of the axial cone lens here is a triangle, and the front view may be a circle, a square, etc., which is not limited in this application. The axial cone lens is thick in the middle and thin around.

[0081] The method for determining the defocusing theory is shown in Figure 11. In defocusing theory, a curved light beam can be viewed as consisting of multiple rays tangent to a curve. Based on this theory, the phase setting that produces the desired light beam can be obtained.

[0082] Specifically, we can first define the curve equation of the beam propagation trajectory (for example, the equation of the curve in Figure 11). Plot the curve in the coordinate system shown in Figure 11. The horizontal axis is the direction of the optical axis, and the vertical axis x represents the distance between the point and the optical axis of the non-diffraction lens 3100. Then, draw a tangent through each point on the curve. The tangent has an intersection with the x-axis. The phase φ(x) of the point is calculated according to the formula, that is, Where k = 2π / λ, where k is the wave number and λ is the wavelength. This gives x = f(z), which is the equation for the beam's propagation trajectory. Based on this principle, the phase gradient and the phase value at a point on the non-diffractive lens 3100 can be used to determine the phase values ​​for all other points.

[0083] It is worth noting that in the aforementioned phase setting method, the obtained non-diffraction beam may be a centrally symmetric beam, but this does not limit the non-diffraction lens 3100 to a circular lens. The non-diffraction lens 3100 may be circular, square, or a portion of a circular lens (e.g., a semicircular lens), and this application does not limit this.

[0084] Optionally, the phase setting of the non-diffraction lens 3100 can be achieved by a lens of a specific shape. Due to the different thickness of the medium at each position of the lens, different additional phases are generated for the incident signal. A corresponding non-diffraction beam is thereby generated. Alternatively, the phase setting of the non-diffraction lens 3100 can also adopt a discrete pixelation method to achieve different transmission phases at a limited number of discrete point positions. For example, the non-diffraction lens 3100 can be a metasurface, a phase plate, or a grating, etc., which is not limited in this application.

[0085] In some optional implementations, it may be necessary for the optical axis of the incident signal to have a certain angle with the non-diffractive lens 3100. That is, the principal optical axis of the incident signal is incident at an angle to the surface of the non-diffractive lens 3100. For example, as shown in FIG12 , the xoy plane is the plane on which the non-diffractive lens 3100 is located, and the xoz plane and the yoz plane are both planes perpendicular to the xoy plane.

[0086] In this structure, the center point of the detection surface 3210 is outside the normal of the non-diffractive lens 3100. The detector 2000 structure provided in the embodiments of the present application can achieve an increased field of view angle and ensure light sensitivity within the field of view angle in an oblique incidence structure, thereby increasing the intensity of light entering the detection surface 3210 and improving the sensitivity of the detector 3000.

[0087] Assume that the angle between the optical axis of the incident signal and the yoz plane is β, and the angle between the optical axis and the xoz plane is γ. Assume that the coordinate position of a point on the non-diffractive lens 3100 is (dx, dy), indicating that a light ray is incident on the non-diffractive lens 3100 from the point (dx, dy). Then the distance between the point and the optical axis of the non-diffractive lens 3100 is

[0088] First, determine the total phase φ(x) produced by each point on the surface of the non-diffractive lens 3100 for the light passing through it using the aforementioned method (e.g., defocus theory). Then, select a point on the surface of the non-diffractive lens 3100 as the reference origin to determine the superimposed phase of the remaining points. For example, if the coordinate position of a point is (dx, dy), then the superimposed phase of this point is That is, the superposition phase caused by the oblique incidence of light. Where λ is the wavelength of the incident signal. The total phase at this point in, is the phase increment produced by the non-diffractive lens 3100 for the vertically incident light.

[0089] The detector 3000 provided in the embodiment of the present application can be used in application scenarios such as sensing and detection.

[0090] For example, the detector 3000 may be a detector in a communication device, which is used to receive and detect signals. The communication device may be an optical communication device, specifically an optical receiving device or an optical transceiver.

[0091] For example, the detector 3000 may be a detector in a sensor device for receiving and detecting sensor signals. The sensor device may be an optical sensor detector, such as an infrared human presence sensor, an infrared temperature sensor, etc., which is not limited in this application.

[0092] Optionally, the detector 3000 may also be a detector in a laser radar, used to receive and detect radar signals.

[0093] In the above applications, the detector 3000 can take into account both a large field of view and high photosensitivity, and can achieve higher sensitivity.

Claims

1. A detector, characterized in that: include: A non-diffraction lens, used for converting the incident signal of the detector into a non-diffraction beam, and converging the non-diffraction beam to the detection surface of the detection unit; The detection unit, the detection surface of the detection unit is used to detect the non-diffraction beam, and the distance d between the detection surface and the non-diffraction lens is smaller than the aperture D of the non-diffraction lens.

2. The detector according to claim 1, characterized in that: The phase increment of the incident signal by the non-diffractive lens is Wherein x is the distance between the incident point of the incident signal on the non-diffractive lens and the optical axis of the non-diffractive lens, is a monotonic function or a constant.

3. The detector according to claim 2, characterized in that: The non-diffracting beam is a Bessel beam, Wherein M is a constant greater than 0.

4. The detector according to claim 2, characterized in that: The non-diffracting beam is an Airy beam, Wherein M is a constant greater than 0.

5. The detector according to claim 2, characterized in that: Said is a monotonically decreasing function.

6. The detector according to claim 5, characterized in that:

7. The detector according to claim 5, characterized in that Wherein λ is the wavelength of the incident signal, a and b are both constants, and a>b.

8. The detector according to any one of claims 1 to 7, characterized in that: d≤0.7D.

9. The detector according to claim 8, characterized in that 0.05D≤d≤0.5D.

10. The detector according to any one of claims 1 to 9, characterized in that: The center point of the detection surface is outside the normal line of the non-diffractive lens.

11. The detector according to any one of claims 1 to 10, characterized in that: The incident signal is a light signal, the detection unit is a photosensitive unit, and the detection surface is a photosensitive surface.

12. The detector according to any one of claims 1 to 10, characterized in that: The incident signal is a signal of a target band, and the target band is within a terahertz band or a millimeter wave band; The detection surface includes a receiving antenna, and the receiving antenna is used to detect signals in the target band.

13. The detector according to any one of claims 1 to 11, characterized in that The non-diffraction lens includes: an axicon lens, a metasurface, a phase plate or a grating.

14. A communication device, characterized in that: A detector comprising the detector described in any one of claims 1 to 13.

15. A sensing device, characterized in that: A detector comprising the detector described in any one of claims 1 to 13.

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