Superlens for polarizing beam splitting, microscope comprising same, and optical communication module

Abstract

The utility model provides a super lens for polarizing beam splitting, a microscope comprising the same and an optical communication module. The super lens provided by the utility model comprises a substrate and a micro-nano structure arranged on the substrate, the micro-nano structure is in polarization correlation; the super lens provides first phase distribution for the received first linearly polarized light so as to deflect and output the first linearly polarized light according to a first angle; the super lens provides second phase distribution for the received second linearly polarized light so as to deflect and output the second linearly polarized light according to a second angle; the polarization direction of the first linearly polarized light is orthogonal to the polarization direction of the second linearly polarized light; the first angle is different from the second angle. According to the super lens for polarization beam splitting, the relative angle between the propagation directions of two types of linearly polarized light obtained through decomposition can be freely controlled, and element miniaturization is facilitated.

Description

Technical Field

[0001] The present application relates to the field of optics, and particularly to a metalens for polarization splitting, a microscope including the same, and an optical communication module. Background Art

[0002] Two types of linearly polarized light with orthogonal polarization directions can be combined into the same light beam. Conversely, the same light beam can also be decomposed into two types of linearly polarized light with orthogonal polarization directions. Therefore, by utilizing the polarization characteristics of the light beam, a polarization splitting element can output two types of linearly polarized light with orthogonal polarization directions corresponding to the incident light at different deflection angles. In this way, the incident light is decomposed into two types of linearly polarized light propagating in different directions.

[0003] Polarization splitting elements have a wide range of applications in fields such as imaging and optical communication. However, in related technologies, it is difficult to freely control the relative angle between the propagation directions of the two types of linearly polarized light obtained by splitting, and it is not conducive to the miniaturization of the element. Summary of the Utility Model

[0004] An object of the present application is to provide a metalens for polarization splitting, a microscope including the same, and an optical communication module. The metalens for polarization splitting provided by the present application can freely control the relative angle between the propagation directions of the two types of linearly polarized light obtained by splitting, and is conducive to the miniaturization of the element.

[0005] According to an aspect of an embodiment of the present application, a metalens for polarization splitting is disclosed. The metalens includes a substrate and a micro-nano structure disposed on the substrate; the micro-nano structure is related to polarization.

[0006] The metalens provides a first phase distribution for the received first linearly polarized light to deflect and output the first linearly polarized light at a first angle.

[0007] The metalens provides a second phase distribution for the received second linearly polarized light to deflect and output the second linearly polarized light at a second angle.

[0008] The polarization direction of the first linearly polarized light is orthogonal to the polarization direction of the second linearly polarized light; the first angle is different from the second angle.

[0009] In an exemplary embodiment of the present application, for the first linearly polarized light with different incident angles, the phase difference between the first phases respectively provided by the same micro-nano structure is less than a preset phase difference threshold, so that the metalens deflects the first linearly polarized light with different incident angles at the first angle.

[0010] In an exemplary embodiment of the present application, for the second linearly polarized light with different incident angles, the phase difference between the second phases provided by the same micro-nano structure is less than a preset phase difference threshold, so that the metalens deflects the second linearly polarized light with different incident angles by a second angle.

[0011] In an exemplary embodiment of the present application, for the first linearly polarized light with the same incident angle, the phase difference between the first phases provided by the micro-nano structures at different positions in the metalens covers the interval of [0, 2π rad], so that the first angle is greater than 0 degrees.

[0012] In an exemplary embodiment of the present application, for the second linearly polarized light with the same incident angle, the phase difference between the second phases provided by the micro-nano structures at different positions in the metalens is less than a preset phase difference threshold, so that the second angle is equal to 0 degrees.

[0013] In an exemplary embodiment of the present application, for the second linearly polarized light with the same incident angle, the phase difference between the second phases provided by the micro-nano structures at different positions in the metalens covers the interval of [0, 2π rad], so that the second angle is greater than 0 degrees.

[0014] In an exemplary embodiment of the present application, the phase difference threshold is 0.1π rad.

[0015] In an exemplary embodiment of the present application, the micro-nano structure is anisotropic.

[0016] According to an aspect of the embodiments of the present application, a microscope is disclosed, and the microscope includes a metalens provided in any of the above embodiments;

[0017] The metalens is used for polarization splitting of the light beam from the sample, so that the microscope images the sample based on the light beam obtained by polarization splitting.

[0018] According to an aspect of the embodiments of the present application, an optical communication module is disclosed, and the optical communication module includes a metalens provided in any of the above embodiments;

[0019] The metalens is used for polarization splitting of the target light beam transmitted in the optical communication module, so that the optical communication module detects the polarization state of the target light beam based on the light beam obtained by polarization splitting.

[0020] In the embodiments of the present application, since the first phase distribution provided by the metalens for the first linearly polarized light can adaptively match the first angle configured for the first linearly polarized light, the first angle can be freely configured according to requirements. Similarly, the second angle can also be freely configured according to requirements. Therefore, the angle difference between the first angle and the second angle can be freely changed; in this way, the metalens can freely control the relative angle between the propagation directions of the two types of linearly polarized light, namely the first linearly polarized light and the second linearly polarized light, obtained by decomposition. Moreover, since the thickness of the substrate in the metalens is usually only a few hundred micrometers and the size of the micro-nano structure is at the nanometer level, compared with the polarization element composed of a right-angle prism in the related art, the volume of the metalens is significantly reduced, which is beneficial to the miniaturization of the element.

[0021] Other features and advantages of the present application will become apparent from the following detailed description, or will be learned in part from the practice of the present application.

[0022] It should be understood that the above general description and the following detailed description are only exemplary and do not limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By referring to the accompanying drawings and describing its exemplary embodiments in detail, the above and other objectives, features, and advantages of the present application will become more apparent.

[0024] Figure 1 The structure and working principle of the metalens provided by the present application are shown.

[0025] Figure 2 The working principle of the metalens in an embodiment of the present application is shown.

[0026] Figure 3 The working principle of the metalens in an embodiment of the present application is shown.

[0027] Figure 4 The working principle of the metalens in an embodiment of the present application is shown.

[0028] Figure 5 The angles of the S light corresponding to the incident light in Embodiment 1 with respect to the x-axis of the two-dimensional plane where the metalens is located before and after being modulated by the metalens are shown.

[0029] Figure 6 The angles of the P light corresponding to the incident light in Embodiment 1 with respect to the x-axis of the two-dimensional plane where the metalens is located before and after being modulated by the metalens are shown.

[0030] Figure 7 The angles of the S light corresponding to the incident light in Embodiment 2 with respect to the x-axis of the two-dimensional plane where the metalens is located before and after being modulated by the metalens are shown.

[0031] Figure 8 Shows the angles of the P - light corresponding to the incident light in Example 2 with respect to the x - axis of the two - dimensional plane where the metalens is located before and after being modulated by the metalens.

[0032] Figure 9 Shows the angles of the S - light corresponding to the incident light in Example 3 with respect to the x - axis of the two - dimensional plane where the metalens is located before and after being modulated by the metalens.

[0033] Figure 10 Shows the angles of the P - light corresponding to the incident light in Example 3 with respect to the x - axis of the two - dimensional plane where the metalens is located before and after being modulated by the metalens.

[0034] Explanation of reference numerals:

[0035] 10 - Metalens; 101 - Substrate; 102 - Micro - nano structure; 21 - First polarized light; 22 - Second polarized light. Detailed implementation manners

[0036] Now, example embodiments will be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these example embodiments are provided so that this application will be more thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The drawings are only schematic illustrations of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted.

[0037] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more example embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the example embodiments of this application. However, those skilled in the art will realize that one or more of the specific details can be omitted in practicing the technical solutions of this application, or other methods, components, steps, etc. can be adopted. In other cases, well - known structures, methods, implementations, or operations are not shown or described in detail to avoid obscuring the aspects of this application.

[0038] In related - art polarization beam - splitting elements, they are usually obtained by gluing the inclined surfaces of two right - angled prisms, and a polarization beam - splitting film is coated on the inclined surface of one of the right - angled prisms; after the incident light irradiates on the inclined surface of the right - angled prism, it is decomposed by the polarization beam - splitting element into two types of linearly polarized lights with perpendicular propagation directions.

[0039] For the two types of linearly polarized light obtained by decomposing incident light by a polarization beam splitter in the related art, their propagation directions are usually always perpendicular to each other, and it is difficult to freely control the relative angle between the propagation directions of the two. Moreover, since the polarization beam splitter in the related art is composed of a right-angle prism, its volume is relatively large, which is not conducive to the miniaturization of the component.

[0040] In consideration of overcoming the above-mentioned defects existing in the related art, the present application provides a metalens for polarization beam splitting. The metalens for polarization beam splitting provided by the present application can freely control the relative angle between the propagation directions of the two types of linearly polarized light obtained by decomposition, and is conducive to the miniaturization of the component.

[0041] Figure 1 The structure and working principle of the metalens provided by the present application are shown. Refer to Figure 1 As shown in, the metalens 10 for polarization beam splitting provided by the present application includes a substrate 101 and a micro-nano structure 102 disposed on the substrate 101. The metalens 10 mainly provides corresponding phases for the received light beam through the micro-nano structures 102 at various positions thereon, so that the received light beam at each position generates a corresponding phase mutation. In this way, a certain phase gradient is generated at each position on the metalens 10, and then a certain modulation effect is exerted on the received light beam at each position.

[0042] In the metalens 10 provided by the present application, the micro-nano structure 102 is polarization-related. Among them, the micro-nano structure 102 being polarization-related can also be referred to as the micro-nano structure 102 being polarization-sensitive. The polarization-related micro-nano structure 102 refers to a micro-nano structure 102 whose optical properties depend on the polarization state of the incident light; that is, for incident light with different polarization states, the polarization-related micro-nano structure 102 can have different optical properties. Specifically, a polarization-related micro-nano structure 102 can be obtained by configuring the cross-sectional geometric shape (for example: a rectangle with unequal length and width; an ellipse), characteristic dimensions (for example: width; height), and arrangement pattern (for example: rhombic lattice arrangement; rectangular lattice arrangement) of the micro-nano structure 102.

[0043] When the micro-nano structure 102 is polarization-related, the same micro-nano structure 102 can provide different phases for polarized light with different polarization directions respectively. At the same time, the phases provided by the micro-nano structures 102 at various positions in the metalens 10 for the light beam together constitute the phase distribution of the metalens 10.

[0044] In this way, by utilizing the fact that the same micro-nano structure 102 can provide different phases for polarized light with different polarization directions, the micro-nano structures 102 at various positions in the superlens 10 are configured such that the micro-nano structures 102 at each position provide a corresponding first phase for the first linearly polarized light 21 and a corresponding second phase for the second linearly polarized light 22. The polarization direction of the first linearly polarized light 21 is orthogonal to the polarization direction of the second linearly polarized light 22.

[0045] The first phases provided by the micro-nano structures 102 at various positions in the superlens 10 for the first linearly polarized light 21 together constitute the first phase distribution of the superlens 10. Under the action of the first phase distribution of the superlens 1, the superlens 10 deflects and outputs the first linearly polarized light 21 at a first angle.

[0046] Similarly, the second phases provided by the micro-nano structures 102 at various positions in the superlens 10 for the second linearly polarized light 22 together constitute the second phase distribution of the superlens 10. Under the action of the second phase distribution of the superlens 10, the superlens 10 deflects and outputs the second linearly polarized light 22 at a second angle.

[0047] It can be understood that when the first linearly polarized light 21 and the second linearly polarized light 22 are actually combined to form the same incident light and then received by the superlens 10, the incident angle of the first linearly polarized light 21 relative to the superlens 10 is equal to the incident angle of the second linearly polarized light 22 relative to the superlens 10; however, in the embodiments of the present application, the first angle at which the superlens 10 deflects the first linearly polarized light 21 is different from the second angle at which the superlens 10 deflects the second linearly polarized light 22. In this way, the incident light received by the superlens 10 will be decomposed into the first linearly polarized light 21 and the second linearly polarized light 22 with different propagation directions.

[0048] Since the first phase distribution provided by the superlens 10 for the first linearly polarized light can adaptively match the first angle configured for the first linearly polarized light 21, the first angle can be freely configured according to requirements. Similarly, the second angle can also be freely configured according to requirements. Thus, the angle difference between the first angle and the second angle can be freely changed; in this way, the superlens 10 can freely control the relative angle between the propagation directions of the two types of linearly polarized light, namely the first linearly polarized light 21 and the second linearly polarized light 22, obtained by decomposition.

[0049] Moreover, since the thickness of the substrate 101 in the superlens 10 is usually only a few hundred micrometers and the size of the micro-nano structure 102 is in the nanometer level, the volume of the superlens 10 is significantly reduced compared to the polarization element composed of a right-angled prism in the related art, which is beneficial to the miniaturization of the component.

[0050] It should be noted that in the embodiments of the present application, "deflecting the first linearly polarized light 21 by a first angle" means that the deflected first linearly polarized light 21 is deflected by the first angle relative to the first linearly polarized light 21 before modulation; similarly, "deflecting the second linearly polarized light 22 by a second angle" means that the deflected second linearly polarized light 22 is deflected by the second angle relative to the second linearly polarized light 22 before modulation.

[0051] In one embodiment, in order to enable the metalens 10 to provide a first phase distribution for the first linearly polarized light 21 and a second phase distribution for the second linearly polarized light 22 at the same time, the meta-structures 102 at various positions on the metalens 10 can be configured in the following manner:

[0052] Determine the first angle by which the first linearly polarized light 21 needs to be deflected. Then, according to the central wavelength, the incident angle of the incident light, and the first angle, calculate the first phase distribution that the metalens 10 should provide for the first linearly polarized light 21, so as to determine the first phase that each position on the metalens 10 should provide for the first linearly polarized light 21

[0053] Similarly, determine the second angle by which the second linearly polarized light 22 needs to be deflected. Then, according to the central wavelength, the incident angle of the incident light, and the second angle, calculate the second phase distribution that the metalens 10 should provide for the second linearly polarized light 22, so as to determine the second phase that each position on the metalens 10 should provide for the second linearly polarized light 22

[0054] Then, the phase combination that the meta-structures 102 at each position on the metalens 10 should provide can be determined.

[0055] Then, for each position on the metalens 10, select the meta-structures 102 from the meta-structure database that can provide the corresponding phase combination and arrange the selected meta-structures 102 at the corresponding positions, that is, the required metalens 10 is designed. The metalens 10 designed in this way can provide a first phase distribution for the first linearly polarized light 21, and thus can deflect the received first linearly polarized light 21 by the first angle and output it; it can provide a second phase distribution for the second linearly polarized light 22, and thus can deflect the received second linearly polarized light 22 by the second angle and output it.

[0056] Among them, the meta-structure database refers to a database for recording the phases provided by the meta-structures 102 with various structural parameters for light beams with various physical properties.

[0057] In one embodiment, for the first linearly polarized light 21 with different incident angles, the phase difference between the first phases provided by the same micro-nano structure 102 is less than a preset phase difference threshold, so that the metalens 10 deflects the first linearly polarized light 21 with different incident angles by a first angle.

[0058] Specifically, in this embodiment, for the first linearly polarized light 21 with different incident angles, the phase difference between the first phases provided by the same micro-nano structure 102 is less than a preset phase difference threshold, indicating that for the first linearly polarized light 21 with different incident angles, the first phases provided by the same micro-nano structure 102 can be approximately equal.

[0059] Therefore, for the first linearly polarized light 21 with different incident angles, the metalens 10 can always provide an approximately identical first phase distribution. In this way, the sensitivity of the metalens 10 to the incident angle when modulating the first linearly polarized light 21 is reduced; regardless of the incident angle at which the incident light enters the metalens 10, within the allowable angular error range, the metalens 10 can deflect the first linearly polarized light 21 in the incident light by the first angle, and will not fail to deflect the first linearly polarized light 21 as expected due to a change in the incident angle, thereby improving the robustness of deflecting the first linearly polarized light 21.

[0060] In this embodiment, the phase difference threshold is less than 0.1π rad; preferably, the phase difference threshold is less than 0.01π rad.

[0061] Figure 2 Illustrates the working principle of the metalens 10 in an embodiment of the present application. Refer to Figure 2 , in one embodiment, the metalens 10 deflects the first linearly polarized light 21 with different incident angles by a first angle θ a1 .

[0062] Specifically, for the first linearly polarized light 211 incident perpendicularly, the metalens 10 deflects it by the first angle θ a1 , so the included angle between the output first linearly polarized light 211 and the normal of the metalens 10 is θ a1 .

[0063] For the first linearly polarized light 212 obliquely incident at an angle θ a2 with the normal, the metalens 10 deflects it by the first angle θ a1 , so the included angle between the output first linearly polarized light 212 and the normal of the metalens 10 is θ a1 + θ a2 .

[0064] For the first linearly polarized light incident at an angle θ a2 + θ a3The first linearly polarized light 213 with an oblique incidence is deflected by the first angle θ by the metalens 10 a1 , so the included angle between the output first linearly polarized light 213 and the normal of the metalens 10 is θ a1 +θ a2 +θ a3 .

[0065] Among them, the first linearly polarized light 211, the first linearly polarized light 212, and the first linearly polarized light 213 may be incident on the metalens 10 at different times and then deflected and output by the metalens 10 respectively, or may be incident on the metalens 10 simultaneously and then deflected and output by the metalens 10 respectively.

[0066] In one embodiment, for the second linearly polarized light 22 with different incident angles, the phase difference between the second phases provided by the same micro-nano structure 102 is less than a preset phase difference threshold, so that the metalens 10 deflects the second linearly polarized light 22 with different incident angles by a second angle.

[0067] Specifically, in this embodiment, for the second linearly polarized light 22 with different incident angles, the phase difference between the second phases provided by the same micro-nano structure 102 is less than a preset phase difference threshold, indicating that for the second linearly polarized light 22 with different incident angles, the second phases provided by the same micro-nano structure 102 can be approximately equal.

[0068] Therefore, for the second linearly polarized light 22 with different incident angles, the metalens 10 can always provide an approximately the same second phase distribution. In this way, the sensitivity of the metalens 10 to the incident angle when modulating the second linearly polarized light 22 is reduced; regardless of the incident angle at which the incident light is incident on the metalens 10, within the allowable angle error range, the metalens 10 can deflect the second linearly polarized light 22 in the incident light by the second angle, and will not fail to deflect the second linearly polarized light 22 by the expected second angle due to the change of the incident angle, thereby improving the robustness of deflecting the second linearly polarized light 22.

[0069] In this embodiment, the phase difference threshold is less than 0.1π rad; preferably, the phase difference threshold is less than 0.01π rad.

[0070] Figure 3 Shows the working principle of the metalens 10 in an embodiment of the present application. See Figure 3 , in one embodiment, the metalens 10 deflects the second linearly polarized light 22 with different incident angles by a second angle θ b1 .

[0071] Specifically, for the second linearly polarized light 221 with a normal incidence, the metalens 10 deflects it by the second angle θ b1, so the angle between the output second linearly polarized light 221 and the normal of the metalens 10 is θ b1 .

[0072] For the second linearly polarized light 222 obliquely incident at an angle θ b2 with respect to the normal, the metalens 10 deflects it by a second angle θ b1 , so the angle between the output second linearly polarized light 222 and the normal of the metalens 10 is θ b1 +θ b2 .

[0073] For the second linearly polarized light 223 obliquely incident at an angle θ b2 +θ b3 with respect to the normal, the metalens 10 deflects it by a second angle θ a1 , so the angle between the output second linearly polarized light 223 and the normal of the metalens 10 is θ b1 +θ b2 +θ b3 .

[0074] Among them, the second linearly polarized light 221, the second linearly polarized light 222, and the second linearly polarized light 223 can be incident on the metalens 10 at different times and then deflected and output by the metalens 10 respectively, or can be incident on the metalens 10 simultaneously and then deflected and output by the metalens 10 respectively.

[0075] In one embodiment, for the first linearly polarized light 21 with the same incident angle, the phase difference between the first phases provided by the micro-nano structures 102 at different positions in the metalens 10 covers the interval [0, 2π rad], so that the first angle is greater than 0 degrees.

[0076] The micro-nano structures 102 provided at any two positions in the metalens 10 can be the same or different. The same micro-nano structure 102 provides the same first phase for the first linearly polarized light 21 with the same incident angle, and different micro-nano structures 102 generally provide different first phases for the first linearly polarized light 21 with the same incident angle.

[0077] Specifically, in this embodiment, for the first linearly polarized light 21 with the same incident angle, the phase difference between the first phases provided by the micro-nano structures 102 at different positions in the metalens 10 covers the interval [0, 2π rad], indicating that for the first linearly polarized light 21 with the same incident angle, non-zero phase gradients can be generated at each position in the metalens 10, and then the metalens 10 can deflect and output the first linearly polarized light 21 at a first angle greater than 0 degrees.

[0078] In one embodiment, for the first linearly polarized light 21 with the same incident angle, the phase difference between the first phases provided by the micro-nano structures 102 at different positions in the metalens 10 covers the interval [0, 2π rad], so that the first angle is greater than 0 degrees. Moreover, for the second linearly polarized light 22 with the same incident angle, the phase difference between the second phases provided by the micro-nano structures at different positions in the metalens 10 is less than a preset phase difference threshold, so that the second angle is equal to 0 degrees.

[0079] Specifically, in this embodiment, the metalens 10 deflects and outputs the first linearly polarized light 21 at a first angle greater than 0 degrees.

[0080] Meanwhile, for the second linearly polarized light 22 with the same incident angle, the phase difference between the second phases provided by the micro-nano structures 102 at different positions in the metalens 10 is less than the preset phase difference threshold, indicating that for the second linearly polarized light 22 with the same incident angle, the second phases provided by the micro-nano structures 102 at different positions in the metalens 10 can be approximately equivalent.

[0081] In this way, for the second linearly polarized light 22 with the same incident angle, the phase gradient generated at each position on the metalens 10 can be approximately 0, so the metalens 10 does not truly deflect the second linearly polarized light 22. Therefore, in this case, within the allowable angular error range, the second angle of deflection of the metalens 10 for the second linearly polarized light 22 is equal to 0 degrees.

[0082] That is, in this embodiment, the metalens 10 deflects the first linearly polarized light 21 at a first angle greater than 0 degrees, but does not deflect the second linearly polarized light 22.

[0083] It should be noted that if the metalens 10 deflects the first linearly polarized light 21 at a first angle greater than 0 degrees and also deflects the second linearly polarized light 22 at a second angle greater than 0 degrees, then it is required that each micro-nano structure 102 has a unique phase response to the first linearly polarized light 21 and the second linearly polarized light 22. At the same time, the unique phase response of the micro-nano structure 102 at each position also needs to exactly meet the combined requirements imposed by the first phase distribution and the second phase distribution for that position. In this way, it is quite difficult to select a suitable micro-nano structure 102.

[0084] However, if the metalens 10 deflects the first linearly polarized light 21 by a first angle greater than 0 degrees but does not deflect the second linearly polarized light 22, it is only required that each micro-nano structure 102 has a unique phase response to the first linearly polarized light. In this way, the unique phase response of the micro-nano structure 102 at each position can more easily meet the combined requirements imposed by the first phase distribution and the second phase distribution at that position. In this way, the difficulty of screening out the appropriate micro-nano structure 102 is reduced.

[0085] Figure 4 shows the working principle of the metalens 10 in an embodiment of the present application. Refer to Figure 4 , in one embodiment, the metalens 10 deflects the first linearly polarized light 21 with different incident angles by a first angle θ greater than 0 degrees a1 and does not deflect the second linearly polarized light 22.

[0086] Specifically, for the first linearly polarized light 211 with normal incidence, the metalens 10 deflects it by the first angle θ a1 , so the included angle between the output first linearly polarized light 211 and the normal of the metalens 10 is θ a1 .

[0087] For the first linearly polarized light 212 obliquely incident at an angle θ with the normal a2 , the metalens 10 deflects it by the first angle θ a1 , so the included angle between the output first linearly polarized light 212 and the normal of the metalens 10 is θ a1 +θ a2 .

[0088] For the first linearly polarized light 213 obliquely incident at an angle θ a2 +θ a3 with the normal, the metalens 10 deflects it by the first angle θ a1 , so the included angle between the output first linearly polarized light 213 and the normal of the metalens 10 is θ a1 +θ a2 +θ a3 .

[0089] At the same time, for the second linearly polarized light 221 obliquely incident at an angle θ b1 with the normal, the metalens 10 does not deflect it, so the included angle between the output second linearly polarized light 221 and the normal of the metalens 10 remains θ b1 .

[0090] For the second linearly polarized light obliquely incident at an angle θ b1 +θ b2For the second linearly polarized light 222 with oblique incidence, the metalens 10 also does not deflect it, so the angle between the output second linearly polarized light 222 and the normal line of the metalens 10 remains θ. b1 +θ b2 .

[0091] For the angle with the normal line being θ b1 +θ b2 +θ b3 For the second linearly polarized light 223 with oblique incidence, the metalens 10 also does not deflect it, so the angle between the output second linearly polarized light 223 and the normal line of the metalens 10 remains θ b1 +θ b2 +θ b3 .

[0092] It should be noted that although the incident angles of the various first linearly polarized lights 21 shown in Figure 4 are different from the incident angles of the various second linearly polarized lights 22, this is only a setting made for the convenience of visually showing that the metalens 10 deflects the first linearly polarized light 21 and the second linearly polarized light 22 by different angles respectively, and does not mean that the incident angle of the first linearly polarized light 21 actually received by the metalens 10 must be different from the incident angle of the second linearly polarized light 22 actually received. As mentioned above, when the first linearly polarized light 21 and the second linearly polarized light 22 are actually combined to form the same incident light and then received by the metalens 10, the incident angle of the first linearly polarized light 21 is equal to the incident angle of the second linearly polarized light 22.

[0093] In one embodiment, for the second linearly polarized light 22 with the same incident angle, the phase difference between the second phases provided by the micro-nano structures 102 at different positions in the metalens 10 covers the interval of [0, 2π rad], so that the second angle is greater than 0 degrees.

[0094] Specifically, in this embodiment, for the second linearly polarized light 22 with the same incident angle, the phase difference between the second phases provided by the micro-nano structures 102 at different positions in the metalens 10 covers the interval of [0, 2π rad], indicating that for the second linearly polarized light 22 with the same incident angle, non-zero phase gradients required can be generated at each position in the metalens 10, and thus the metalens 10 can deflect and output the second linearly polarized light 22 at a second angle greater than 0 degrees.

[0095] In one embodiment, each of the micro-nano structures 102 in the metalens 10 is anisotropic, thereby making the micro-nano structures 102 polarization-related.

[0096] This application also provides a microscope. The microscope includes the metalens 10 provided in any one of the above embodiments.

[0097] The microscope is used to image a sample for the user to observe the morphology of the sample based on the obtained image. In this microscope, the metalens 10 is used to perform polarization splitting on the light beam from the sample, decompose the first linearly polarized light and the second linearly polarized light from the sample, and make the first linearly polarized light and the second linearly polarized light propagate in different directions. For the decomposed first linearly polarized light and second linearly polarized light, the microscope can respectively perform phase modulation and guidance on the two to cause interference between them, thereby enhancing or weakening the brightness of a specific area in the obtained image, and further enhancing the contrast of the obtained image and improving the clarity of the sample details in the image.

[0098] This application also provides an optical communication module. The optical communication module includes the metalens 10 provided in any of the above embodiments.

[0099] The optical communication module is used to detect the polarization state of the target light beam transmitted therein. In this optical communication module, the metalens 10 is used to perform polarization splitting on the target light beam, and decompose the first linearly polarized light and the second linearly polarized light that make up the target light beam.

[0100] For target light beams with different polarization states, their amplitude distributions on the first linearly polarized light and the second linearly polarized light are different. Therefore, after decomposing the first linearly polarized light and the second linearly polarized light that make up the target light beam, by detecting the amplitude distributions of the first linearly polarized light and the second linearly polarized light, the polarization state of the target light beam can be determined.

[0101] Embodiment 1

[0102] Figure 5 Shows the angles of the S light corresponding to the incident light in Embodiment 1 before and after being modulated by the metalens 10 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located. Figure 6 Shows the angles of the P light corresponding to the incident light in Embodiment 1 before and after being modulated by the metalens 10 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located. Among them, S light refers to the polarized light whose electric field vibration direction is perpendicular to the incident plane, and P light refers to the polarized light whose electric field vibration direction is parallel to the incident plane; the polarization direction of S light is orthogonal to the polarization direction of P light.

[0103] In Figure 5 and Figure 6 the bar on the right represents the light intensity; the horizontal axis represents the coordinate of the x-axis of the two-dimensional plane where the metalens 10 is located, and the origin of the horizontal axis is the position of the center of the metalens 10; the vertical axis represents the coordinate of the z-axis perpendicular to the two-dimensional plane where the metalens 10 is located; when the z-axis coordinate is negative, it means the light beam has not been modulated by the metalens 10; when the z-axis coordinate is 0, it means the light beam just shines on the metalens 10; when the z-axis coordinate is positive, it means the light beam has been modulated by the metalens 10.

[0104] In Example 1, the central wavelength of the incident light is 940 nm, and when the incident light is not modulated by the metalens 10, the angle of the incident light with respect to the x-axis is -2.5°.

[0105] See Figure 5 , when the incident light is S light, after being modulated by the metalens 10 and exiting the metalens 10, its angle with respect to the x-axis is 12.5°. That is, when the incident light is S light, the metalens 10 deflects the incident light by 15°.

[0106] See Figure 6 , when the incident light is P light, after being modulated by the metalens 10 and exiting the metalens 10, its angle with respect to the x-axis remains -2.5°. That is, when the incident light is P light, the metalens 10 does not deflect the incident light.

[0107] Example 2

[0108] Figure 7 Shows the angles of the S light corresponding to the incident light in Example 2 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located before and after being modulated by the metalens 10. Figure 8 Shows the angles of the P light corresponding to the incident light in Example 2 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located before and after being modulated by the metalens 10.

[0109] In Example 2, the central wavelength of the incident light is 940 nm, and when the incident light is not modulated by the metalens 10, the angle of the incident light with respect to the x-axis is 17.5°.

[0110] See Figure 7 , when the incident light is S light, after being modulated by the metalens 10 and exiting the metalens 10, its angle with respect to the x-axis is 32.5°. That is, when the incident light is S light, the metalens 10 deflects the incident light by 15°.

[0111] See Figure 8 , when the incident light is P light, after being modulated by the metalens 10 and exiting the metalens 10, its angle with respect to the x-axis remains 17.5°. That is, when the incident light is P light, the metalens 10 does not deflect the incident light.

[0112] Example 3

[0113] Figure 9 Shows the angles of the S light corresponding to the incident light in Example 3 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located before and after being modulated by the metalens 10. Figure 10 Shows the angles of the P light corresponding to the incident light in Example 3 with respect to the x-axis of the two-dimensional plane where the metalens 10 is located before and after being modulated by the metalens 10.

[0114] In Embodiment 3, the central wavelength of the incident light is 940 nm, and when the incident light is not modulated by the metalens 10, the angle of the incident light relative to the x-axis is 7.5°.

[0115] Referring to Figure 9 , when the incident light is S light, after being modulated by the metalens 10 and exiting from the metalens 10, the angle of the incident light relative to the x-axis is 22.5°. That is, when the incident light is S light, the metalens 10 deflects the incident light by 15°.

[0116] Referring to Figure 10 , when the incident light is P light, after being modulated by the metalens 10 and exiting from the metalens 10, the angle of the incident light relative to the x-axis is still 7.5°. That is, when the incident light is P light, the metalens 10 does not deflect the incident light.

[0117] After considering the specification and practicing the disclosed utility model herein, those skilled in the art will readily conceive of other embodiments of the present application. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include well-known knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only regarded as exemplary, and the true scope and spirit of the present application are pointed out by the appended claims.

Claims

1. A metalens for polarization splitting, characterized in that: The superlens includes a substrate and a micro-nano structure disposed on the substrate; the micro-nano structure is polarization-dependent; The metalens provides a first phase distribution for the received first linearly polarized light, so as to deflect and output the first linearly polarized light at a first angle; The metalens provides a second phase distribution for the received second linearly polarized light, so as to deflect and output the second linearly polarized light at a second angle; The polarization direction of the first linear polarized light is orthogonal to the polarization direction of the second linear polarized light; and the first angle is different from the second angle.

2. The metalens according to claim 1, characterized in that For the first linear polarized light with different incident angles, the phase difference between the first phases respectively provided by the same micro-nano structure is less than a preset phase difference threshold, so that the metalens deflects the first linear polarized light with different incident angles by the first angle.

3. The metalens according to claim 1, characterized in that For the second linear polarized light with different incident angles, the phase difference between the second phases respectively provided by the same micro-nano structure is less than a preset phase difference threshold, so that the metalens deflects the second linear polarized light with different incident angles by the second angle.

4. The metalens according to claim 1, wherein: For the first linearly polarized light with the same incident angle, the phase difference between the first phases respectively provided by the micro-nano structures at different positions in the metalens covers the interval [0, 2πrad], so that the first angle is greater than 0 degree.

5. The superlens according to claim 4, characterized in that For the second linearly polarized light with the same incident angle, the phase difference between the second phases respectively provided by the micro-nano structures at different positions in the metalens is less than a preset phase difference threshold, so that the second angle is equal to 0 degree.

6. The metalens according to claim 1, characterized in that For the second linearly polarized light with the same incident angle, the phase difference between the second phases respectively provided by the micro-nano structures at different positions in the metalens covers the interval [0, 2πrad], so that the second angle is greater than 0 degree.

7. The metalens according to claim 2, 3 or 5, characterized in that: The phase difference threshold is 0.1πrad.

8. The metalens according to claim 1, characterized in that The micro-nano structure is anisotropic.

9. A microscope, characterized in that: The microscope comprises a superlens as claimed in any one of claims 1 to 8; The super lens is used to perform polarization splitting on the light beam from the sample, so that the microscope can image the sample based on the light beam obtained by polarization splitting.

10. An optical communication module, characterized in that: The optical communication module comprises a superlens as described in any one of claims 1 to 8; The superlens is used to perform polarization splitting on the target light beam transmitted in the optical communication module, so that the optical communication module detects the polarization state of the target light beam based on the light beam obtained by polarization splitting.

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