A multi-dimensional encryption method based on elliptical orbital angular momentum microlaser array

Abstract

The present invention discloses a multidimensional encryption method and system based on an elliptical orbital angular momentum microlaser array. The method constructs a dielectric elliptical microring array structure in a Fabry-Perot microcavity to perform multidimensional encoding of the elliptical orbital angular momentum (OAM) mode, thereby achieving multidimensional optical encryption. The encoding dimensions include the angular order (l), radial order (p), ellipticity (∈), and major axis direction (θ) of the elliptical OAM mode. This invention significantly expands the encoding dimensions of mode-division multiplexing optical encryption and has significant potential in high-security anti-counterfeiting and information storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical encryption, and in particular relates to a multi-dimensional encryption method based on an elliptical orbital angular momentum (OAM) microlaser array. Background Art

[0002] Optical encryption technology has garnered significant attention in recent years due to its multi-dimensional encoding, high parallelism, and large-capacity information storage capabilities. The core of optical encryption lies in utilizing photons as information carriers. By constructing precision photonic devices, data can be encoded into specific optical dimensions, such as wavelength, polarization, amplitude, and spatial pattern. By increasing the optical encoding dimension, encryption complexity can be significantly increased, thereby enhancing information security.

[0003] An effective method to expand the coding dimension of optical encryption is to multiplex various spatial modes of photons, namely mode division multiplexing. Mode division multiplexing encryption uses spatial modes of different orders as encryption channels, where the mode order is usually used as the coding dimension. For example, complex optical encryption functions can be achieved by encoding the angular order of orbital angular momentum (OAM) modes. However, relying solely on the mode order as a single coding dimension still limits the complexity of mode division multiplexing, thereby limiting the improvement of encryption security.

[0004] At the same time, microcavity lasers have made significant progress in optical encryption. The lasers emitted by microcavity lasers have multidimensional optical properties, which can be encoded by regulating the optical properties of micro-nanomaterials in the cavity. Therefore, microcavity lasers show great potential in multidimensional optical encryption. More importantly, microcavities support multiple transverse mode oscillations, providing a broad coding space for mode division multiplexing optical encryption. However, due to the lack of effective methods to accurately control transverse mode oscillations, current optical encryption schemes based on microcavity lasers are still limited to lower optical dimensions (number of dimensions ≤ 2). Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a multi-dimensional encryption method based on an elliptical OAM microlaser array. The method constructs a dielectric elliptical ring array structure in a Fabry-Perot microcavity to generate an elliptical OAM mode laser array with multi-dimensional encrypted information. The physical parameters of each elliptical ring in the elliptical ring array are regulated by photolithography technology, thereby encoding the elliptical OAM mode generated at each position in the array. The encoding dimensions include the angular order (l), radial order (p), ellipticity (∈), and major axis direction (θ) of the elliptical OAM mode. During the decoding process, the encrypted information can only be restored if the elliptical OAM mode laser array is correctly parsed in these four dimensions.

[0006] The technical solutions of the present invention are as follows:

[0007] On the one hand, the present invention provides a multi-dimensional encryption method based on an elliptical orbital angular momentum microlaser array, which is characterized in that the method includes:

[0008] Step 1. Construct an elliptical OAM microcavity array; the elliptical OAM microcavity array is composed of a plurality of elliptical OAM microcavities, each elliptical OAM microcavity consisting of two parallel laser cavity mirrors, a dielectric elliptical ring array is processed on the surface of one of the cavity mirrors, and a fluorescent dye solution is encapsulated as a gain medium between the two laser cavity mirrors; wherein each elliptical ring in the dielectric elliptical ring array has specific physical parameters, including the major and minor axes and major axis direction of the inner ring and the major and minor axes and major axis direction of the outer ring;

[0009] Step 2. By exciting photons to oscillate laterally along each elliptical ring in the elliptical OAM microcavity, an elliptical OAM mode with encoded information is generated at each position in the dielectric elliptical ring array (the encoded information is controlled by the physical parameters of each elliptical ring in step 1), thereby forming an elliptical OAM mode laser array with multi-dimensional encrypted information, wherein the encoding dimensions include the angular order l, the radial order p, the ellipticity ∈ and the major axis direction θ.

[0010] Furthermore, the method further includes a decoding step 3: parsing the received elliptical OAM mode laser array in the four coding dimensions to restore the encrypted information.

[0011] Furthermore, the encoding rule of the elliptical OAM mode is:

[0012] The angular order l is controlled by the inner circumference of the ellipse. When the angular order l≤l0, it is encoded as "0"; when l>l0, it is encoded as "1";

[0013] The radial order p is controlled by the difference between the major axes of the inner and outer rings of the elliptical ring. When the radial order p≤p0, it is encoded as "0"; when p>p0, it is encoded as "1";

[0014] The ellipticity ε is controlled by the ratio of the major and minor axes of the inner ring of the elliptical ring. When the ellipticity ε≤ε0, it is encoded as "0"; when ε>ε0, it is encoded as "1";

[0015] The major axis direction θ is controlled by the major axis directions of the inner and outer rings of the ellipse. When the major axis direction θ≤θ0, it is encoded as "0"; when θ>θ0, it is encoded as "1";

[0016] Among them, l0, p0, ε0, θ0 are the physical parameter thresholds of each elliptical OAM mode set as the key threshold.

[0017] Furthermore, the step 3 specifically includes:

[0018] Step 3.1: Use pump light to excite each elliptical ring in the elliptical ring array, and use a CCD to record the elliptical OAM mode laser image output at each elliptical ring position;

[0019] Step 3.2: stitching the elliptical OAM mode laser images outputted from each elliptical ring position to obtain an elliptical OAM mode laser array image;

[0020] Step 3.3 characterizes each elliptical OAM mode of the elliptical OAM mode laser array image, including the angular order l, radial mode order p, ellipticity ∈, and major axis direction θ, so as to decode the encrypted information.

[0021] Furthermore, the characterization method of the elliptical OAM mode in step 3.3 is as follows:

[0022] The angular order l of the elliptical OAM mode is determined by the number of nodal lines along the angular direction in the laser pattern, i.e. l ​​= number of nodal lines / 2;

[0023] --The radial order p of the elliptical OAM mode is determined by the number of rings in the laser pattern, that is, p = number of rings - 1.

[0024] --The ellipticity ∈ and major axis direction θ of the elliptic OAM mode are determined by fitting the laser intensity distribution using an elliptic function. The ellipticity ∈ and major axis direction θ of the fitted elliptic function are the ellipticity ∈ and major axis direction θ of the elliptic OAM mode.

[0025] On the other hand, the present invention also provides a multi-dimensional encryption system based on an elliptical orbital angular momentum micro-laser array, which is characterized in that the system includes:

[0026] Fabry-Perot microcavity, in which a dielectric elliptical microring array structure is constructed;

[0027] a processing device for controlling the physical parameters of each ellipse in the dielectric elliptical microring array using photolithography technology;

[0028] The encoding module adjusts the physical parameters of the ellipse according to the required encoding information and encodes the ellipse OAM mode;

[0029] A pump source, used to excite the Fabry-Perot microcavity to generate an elliptical OAM mode laser array containing multi-dimensional encrypted information;

[0030] The decryption module is used to measure and analyze the image of the elliptical OAM mode laser array and restore the encrypted information.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] Unlike traditional optical encryption methods, which rely on limited encoding dimensions such as amplitude, phase, or polarization state, this invention achieves multidimensional encoding of elliptical OAM modes by constructing a dielectric elliptical microring array structure within a Fabry-Perot microcavity. This not only encompasses the angular and radial orders of the elliptical OAM mode, but also introduces ellipticity and major axis orientation as new encoding parameters, significantly enriching the "cryptographic library" of information encryption and achieving a qualitative leap in the complexity and security of the encryption system. Furthermore, the random major axis orientation and processing errors of the elliptical rings enhance anti-counterfeiting properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a structural diagram of a micro-laser array used for multi-dimensional optical encryption according to an embodiment of the present invention.

[0034] Figure 2 Schematic diagram of an embodiment of the present invention characterizing an elliptical OAM mode

[0035] Figure 3 The present invention is a microscope system for measuring laser images.

[0036] Figure 4 The embodiment of the present invention uses an elliptical OAM microlaser array to achieve four-dimensional encrypted optical images.

[0037] In the picture:

[0038] 1. First laser cavity mirror; 2. Dielectric elliptical ring; 3. Second laser cavity mirror; 4. Gain medium; 5. Pump light; 6. Microcavity; 7. Elliptical OAM mode laser; 8. Elliptical OAM microcavity array; 9. Elliptical OAM mode laser array; 10. Laser image after decoding the elliptical OAM mode laser array; 11. Image of an OAM mode laser in the laser array; 12. Pump source; 13. Spectrometer; 14. Objective lens; 15. Reflector; 16. Convex lens; 17. CCD camera. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below with reference to the accompanying drawings. In order to generate an elliptical OAM mode laser array with multi-dimensional encrypted information, a Fabry-Perot microcavity structure integrated with a dielectric elliptical ring array is designed and constructed. Figure 1 As shown, the microcavity 6 is composed of two parallel laser cavity mirrors 1 and 3, and the dielectric elliptical ring 2 is processed on the surface of the first laser cavity mirror 1. In addition, a fluorescent dye solution is encapsulated in the microcavity as a gain medium 4.

[0040] Since the refractive index of the elliptical ring is higher than that of the surrounding environment, the excited photons can oscillate transversely along the elliptical orbit, thus forming an elliptical OAM mode. This elliptical OAM mode can be characterized by four independent parameters: angular order (l), radial order (p), ellipticity (∈), and major axis direction (θ). Figure 2 As shown, the angular order l of the elliptical OAM mode is determined by the number of nodal lines along the angular direction in the laser pattern. The number of nodal lines is 2l, and dividing it by 2 is the angular order of the elliptical OAM laser mode. The radial order p of the elliptical OAM mode is determined by the number of rings in the laser pattern. The number of rings in the laser pattern is p+1, and subtracting it by 1 is the radial order of the elliptical OAM laser mode. The ellipticity ∈ and the major axis direction θ of the elliptical OAM mode are determined by fitting the laser intensity distribution using an elliptical function. The ellipticity ∈ and the major axis direction θ of the fitted elliptical function are the ellipticity ∈ and the major axis direction θ of the elliptical OAM mode. ∈=a / b, where a and b represent the major and minor semi-axis of the fitted elliptical function, respectively. These four parameters l, p, ∈, and θ constitute the four independent optical dimensions of the elliptical OAM mode. By controlling the physical properties of the elliptical rings in the cavity, these four parameters of the elliptical OAM mode can be manipulated to achieve four-dimensional encoding. Encoding rules:

[0041] Coding Dimension "0” "1” Angular order <![CDATA[l≤l0]]> <![CDATA[l>l0]]> Radial order <![CDATA[p≤p0]]> <![CDATA[p>p0]]> Ellipsometric <![CDATA[ε≤ε0]]> <![CDATA[ε>e0]]> Long axis direction <![CDATA[θ≤θ0]]> <![CDATA[θ>θ0]]>

[0042] The control and encoding methods for the elliptical OAM mode are as follows: (1) The angular order l of the elliptical OAM mode is controlled by the circumference of the inner ring, and the laser mode with l≤l0 is encoded as "0", and the laser mode with l>l0 is encoded as "1". (2) The radial order p of the elliptical OAM mode is controlled by the difference between the major axes of the inner and outer rings, and the laser mode with p≤p0 is encoded as "0", and the laser mode with p>p0 is encoded as "1". (3) The ellipticity ∈ of the elliptical OAM mode is controlled by the ratio of the major and minor axes of the inner ring, and the laser mode with ε≤ε0 is encoded as "0", and the laser mode with ε>ε0 is encoded as "1". (4) The major axis direction θ of the elliptical OAM mode is controlled by the major axis direction of the inner and outer rings, and the laser mode with θ≤θ0 is encoded as "0", and the laser mode with θ>θ0 is encoded as "1".

[0043] By constructing an elliptical OAM microcavity array 8, four specially designed patterns (such as "U", "S", "S", and "T") can be simultaneously encoded into the elliptical OAM mode laser array 9. The correct key (l0 = 11, p0 = 0, ε0 = 1.6, θ0 = 45°) is required to decode the elliptical OAM mode laser array 9 in order to restore the encrypted information 10, such as Figure 4As shown. In the elliptical OAM laser array 9, "1" represents a larger parameter (i.e., l>l0, p>p0, ε>ε0, or θ>θ0). The decoded information 10 displays four letter patterns, namely "U," "S," "S," and "T." These encrypted patterns can only be obtained by analyzing the elliptical OAM mode laser array image with the correct decoding key (l0, p0, ε0, θ0).

[0044] Laser image measurement system Figure 3 As shown, it includes a pump source 12, a spectroscope 13, an objective lens 14, a reflector 15, a convex lens 16, and a CCD camera 17. The laser emitted by the pump source 12 has a repetition frequency of 50 Hz, a pulse duration of 9 ns, and a wavelength of 532 nm. The pump laser beam is reflected by the spectroscope 13 to the objective lens 14 and focuses the laser on the elliptical ring in the microcavity 6. As shown in Figure 2, the inner ring semi-major axis is 18.1 microns, the inner ring semi-minor axis is 9.7 microns, the outer ring semi-major axis is 36.7 microns, and the outer ring semi-minor axis is 27.9 microns. The generated elliptical OAM mode passes through the objective lens 14 and the spectroscope 13, is reflected by the reflector 15, and is focused by the convex lens 16 and incident on the CCD camera 17, thereby recording the laser image 7.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-dimensional encryption method based on an elliptical orbital angular momentum micro-laser array, characterized in that: The method includes: Step 1. Construct an elliptical OAM microcavity array; the elliptical OAM microcavity array is composed of a plurality of elliptical OAM microcavities, each elliptical OAM microcavity consisting of two parallel laser cavity mirrors, a dielectric elliptical ring array is processed on the surface of one of the cavity mirrors, and a fluorescent dye solution is encapsulated as a gain medium between the two laser cavity mirrors; wherein each elliptical ring in the dielectric elliptical ring array has specific physical parameters, including the major and minor axes and major axis direction of the inner ring and the major and minor axes and major axis direction of the outer ring; Step 2. By exciting photons to oscillate transversely along each elliptical ring in the elliptical OAM microcavity, an elliptical OAM mode with encoded information is generated at each position in the dielectric elliptical ring array, thereby forming an elliptical OAM mode laser array with multi-dimensional encrypted information, wherein the encoding dimensions include the angular order l, the radial order p, the ellipticity ∈, and the major axis direction θ; Step 3: parsing the received elliptical OAM mode laser array in the four coding dimensions to restore the encrypted information, specifically comprising: Step 3.1: Use pump light to excite each elliptical ring in the elliptical ring array, and use a CCD to record the elliptical OAM mode laser image output at each elliptical ring position; Step 3.2: stitching the elliptical OAM mode laser images outputted from each elliptical ring position to obtain an elliptical OAM mode laser array image; Step 3.3 characterizes each elliptical OAM mode of the elliptical OAM mode laser array image, including the angular order l, radial mode order p, ellipticity ∈, and major axis direction θ, so as to decode the encrypted information. The characterization method of the elliptical OAM mode is as follows: The angular order l of the elliptical OAM mode is determined by the number of nodal lines along the angular direction in the laser pattern, i.e. l ​​= number of nodal lines / 2; --The radial order p of the elliptical OAM mode is determined by the number of rings in the laser pattern, i.e., p = number of rings - 1; --The ellipticity ∈ and major axis direction θ of the elliptic OAM mode are determined by fitting the laser intensity distribution using an elliptic function. The ellipticity ∈ and major axis direction θ of the fitted elliptic function are the ellipticity ∈ and major axis direction θ of the elliptic OAM mode.

2. The multi-dimensional encryption method based on elliptical orbital angular momentum micro-laser array according to claim 1, characterized in that: The encoding rules of the elliptical OAM mode are: The angular order l is controlled by the inner circumference of the ellipse. When the angular order l≤l0, it is encoded as "0"; when l>l0, it is encoded as "1"; The radial order p is controlled by the difference between the major axes of the inner and outer rings of the elliptical ring. When the radial order p≤p0, it is encoded as "0"; when p>p0, it is encoded as "1"; Ellipsometric degree ∈ is controlled by the ratio of the major and minor axes of the inner ring of the elliptical ring. When the ellipsometric degree ∈≤∈0, it is coded as "0"; when ∈>∈0, it is coded as "1"; The major axis direction θ is controlled by the major axis directions of the inner and outer rings of the elliptical ring. When the major axis direction θ≤θ0, it is encoded as "0"; when θ>θ0, it is encoded as "1"; Among them, l0, p0,∈0, θ0 is the physical parameter threshold of each elliptical OAM mode set as the key threshold.

3. A multi-dimensional encryption system based on an elliptical orbital angular momentum microlaser array, using the multi-dimensional encryption method according to claim 1 or 2, characterized in that: The system includes: Fabry-Perot microcavity, in which a dielectric elliptical microring array structure is constructed; a processing device for controlling the physical parameters of each ellipse in the dielectric elliptical microring array using photolithography technology; The encoding module adjusts the physical parameters of the ellipse according to the required encoding information and encodes the ellipse OAM mode; A pump source, used to excite the Fabry-Perot microcavity to generate an elliptical OAM mode laser array containing multi-dimensional encrypted information; The decryption module is used to measure and analyze the image of the elliptical OAM mode laser array and restore the encrypted information.

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