A random number generator based on random laser

Abstract

The application provides a random number generator based on random laser, comprising: a non-coherent random laser light source system and a data post-processing system; the non-coherent random laser light source system comprises an excitation light source, a cylindrical microlens array, a PDMS substrate and a dye solution dropped on the upper surface of the PDMS substrate, wherein the excitation light source is used for outputting pump laser, the cylindrical microlens array is used for receiving the pump laser and irradiating the PDMS substrate after processing the pump laser, and the processed pump laser takes the dye solution dropped on the surface of the PDMS substrate as a gain medium to generate random laser; the data post-processing system comprises a spectrometer, the spectrometer is used for receiving random laser, and the laser data is post-processed through fitting, high-order finite difference and selection of the lowest significant bit, so that a random number sequence is generated. The application can greatly improve the random number generation rate.

Description

Technical Field

[0001] This invention relates to the fields of information encryption, communication, cryptography, and more particularly to a random number generator based on random laser. Background Technology

[0002] Random number generators are of significant value in information encryption and communication. Based on the method of generation, random numbers are generally classified as true random or pseudo-random. Pseudo-random number generators use random numbers as seeds to generate a random number sequence through algorithms; this sequence exhibits periodicity. True random number generators, on the other hand, generate non-reproducible and non-periodic random number sequences based on random and unpredictable physical processes, offering stronger security for encrypting and transmitting confidential information.

[0003] Currently, the random number sources for true random number generators typically include thermal noise, photoelectric effect, and chaotic semiconductor lasers. Among these, random number generators based on chaotic semiconductor lasers have seen rapid development in recent years, with the fastest generation speed reaching 250 Tbit / s. However, these random number generators also suffer from high cost and cumbersome signal post-processing. Meanwhile, using low-cost random lasers can also achieve relatively high-quality and fast random number generators, but this has yet to be explored or reported. Summary of the Invention

[0004] To address the technical problems of high cost and cumbersome signal processing in existing random number generators, this invention provides a random number generator based on random lasers. This invention generates random numbers using random lasers, significantly improving the generation speed.

[0005] The technical means employed in this invention are as follows:

[0006] A random number generator based on random laser includes: an incoherent random laser source system and a data post-processing system;

[0007] The incoherent random laser source system includes an excitation source, a laser shaping mechanism, a PDMS substrate, and a dye solution dropped onto the surface of the PDMS substrate. The excitation source is used to output a pump laser, and the laser shaping mechanism is used to receive the pump laser and process it before irradiating the PDMS substrate. The processed pump laser uses the dye solution dropped onto the surface of the PDMS substrate as a gain medium to generate random laser. The laser shaping mechanism includes a cylindrical concave lens and a cylindrical microconvex lens array.

[0008] The data post-processing system includes a spectrometer, which receives random laser light and performs post-processing on the laser data by fitting, high-order finite difference, and selecting the least significant bit, thereby generating a random number sequence.

[0009] Furthermore, the upper surface of the PDMS substrate has a grooved microstructure.

[0010] Furthermore, the PDMS substrate is prepared according to the following method:

[0011] A silica gel solution and a crosslinking agent were mixed in a ratio of 10:1 and placed in a vacuum chamber for 90 minutes to remove air bubbles, thus obtaining a PDMS solution.

[0012] The PDMS solution is poured onto the inner surface of the abalone shell, filling the groove structure on the inner surface of the abalone shell.

[0013] The PDMS layer was cured at 80°C for 180 minutes and then peeled off from the inner surface of the abalone shell to form a negative template.

[0014] A 30nm thick HfO2 film was coated on the grooved surface of the negative template by atomic layer deposition to form an anti-adhesion layer, thus completing the first PDMS replication.

[0015] A second PDMS replication was performed on the negative template, and the PDMS substrate required for the experiment was successfully prepared.

[0016] Furthermore, the pump laser is processed by the laser shaping mechanism, including:

[0017] After the pump laser is laterally expanded by a cylindrical concave lens, it is irradiated onto the cylindrical microconvex lens array.

[0018] The expanded laser beam is longitudinally focused to form a linear spot by a cylindrical micro-convex lens array, which is a square array composed of 16*16 cylindrical micro-convex lenses.

[0019] Furthermore, the dye solution is a 1mM Rhodamine 640 dye solution, and the solvent is ethanol.

[0020] Furthermore, the fitting process for the random laser includes:

[0021] The incoherent random laser spectrum collected by the spectrometer is fitted to obtain the theoretical incoherent random laser spectrum. Then, the theoretical incoherent random laser spectrum is subtracted from the incoherent random laser spectrum to obtain the hidden coherent random laser spectrum signal.

[0022] Furthermore, higher-order finite difference finite differences are performed on the hidden coherent random laser spectral signal, including:

[0023] A third-order difference calculation is performed on the sampling points with equal wavelength intervals in the hidden coherent random laser spectrum.

[0024]

[0025] Where m equals 3, n represents the interval between adjacent data points, and I represents the spectral intensity of the data points, thus obtaining the light intensity sequence after eliminating statistical bias.

[0026] Furthermore, the light intensity sequence after eliminating statistical bias is converted to binary, and then 4 least significant bits are selected to generate a random number sequence.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. This invention designs an optical random number generator based on hidden modes in random laser spectra. The random laser is generated using a dye as the gain medium. Commonly observed incoherent random laser spectra in experiments typically contain a certain amount of coherent random laser components, manifested as numerous small spikes at the spectral peaks. By subtracting the fitted incoherent random laser spectrum (a smooth single-peak curve), a series of spikes can be obtained, i.e., the coherent random laser signal. Due to the randomness of multiple scattering, the spectral signal obtained from each pulse is non-reproducible. Defining this spectral signal yields a sequence of random numbers.

[0029] 2. The ratio of coherent to incoherent random laser light can be adjusted by changing conditions such as scattering intensity and gain. Furthermore, by changing conditions such as pump intensity, pump fringe length, number of pump fringe, dye concentration, repetition rate, and digital generation algorithm used in this invention, the resulting random number sequence can be optimized to meet corresponding testing requirements. For example, the ratio of coherent random laser light increases with increasing pump intensity, pump fringe length, and dye concentration.

[0030] 3. This invention can significantly improve the random number generation rate, theoretically reaching 810 Tbit / s, which is faster than all currently known post-processing-based optical random number generators. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the random number generator structure based on random laser of the present invention.

[0033] Figure 2 shows the front and top views of the ten parallel linear pump beams formed after the laser light passes through the cylindrical microlens array of the present invention. Figure 2a Main view, Figure 2bThis is a top view.

[0034] Figure 3 This is a schematic diagram of the post-processing of experimental data in this invention. The left image is post-processed to obtain the right image.

[0035] Figure 4 This is the highest sampling rate of this invention. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1 As shown, the present invention discloses a random number generator based on random laser, which mainly includes: an incoherent random laser source system and a data post-processing system.

[0039] An incoherent random laser source system includes an excitation source, a laser shaping mechanism, a PDMS substrate, and a dye solution dropped onto the surface of the PDMS substrate. The excitation source is used to output a pump laser, and the laser shaping mechanism is used to receive the pump laser and process it before irradiating the PDMS substrate. The processed pump laser uses the dye solution dropped onto the surface of the PDMS substrate as a gain medium to generate random laser. The laser shaping mechanism includes a cylindrical concave lens and a cylindrical microconvex lens array.

[0040] First, a PDMS substrate needs to be prepared. A silica gel solution and a crosslinking agent are mixed at a 10:1 ratio and placed in a vacuum chamber for 90 minutes to remove air bubbles, resulting in a PDMS solution. Then, a PDMS substrate with a grooved microstructure is fabricated using soft photolithography. Specifically, the silica gel solution and crosslinking agent are mixed at a 10:1 ratio and placed in a vacuum chamber for 90 minutes to remove air bubbles, resulting in a PDMS solution. Approximately 20 mL of the solution is then poured onto the inner surface of an abalone shell, filling the grooved structure. After curing at 80°C for 180 minutes, the PDMS layer is peeled off from the inner surface of the abalone shell to form a negative template. Then, a 30 nm thick HfO2 film is coated onto the grooved surface of the negative template using atomic layer deposition (ALD) to form an anti-adhesion layer, completing the first PDMS replication. Finally, approximately 20 mL of the PDMS solution is poured onto the negative template with the film coating, filling the grooved structure on its surface. After curing at 80℃ for 180 minutes, the PDMS layer was peeled off from the negative template, completing the second PDMS replication of the negative template, and finally successfully preparing the PDMS substrate required for the experiment. 0.012g of Rhodamine 640 dye was dissolved in 20mL of ethanol to prepare a 1mM Rhodamine 640 ethanol solution. Approximately 2mL of the dye solution was dropped onto the surface of the PDMS substrate as a gain medium, and then a PDMS transparent cover sheet of approximately 3mm thickness was attached to create a random laser.

[0041] When the random laser operates, the second harmonic of a 1064nm Nd:YAG solid-state laser with a repetition rate of 10Hz, at 532nm, is used as the pump light. First, a cylindrical concave lens with a focal length of 50mm and dimensions (length*width*height) of 20*20*3mm is used to laterally expand the circular pump laser beam. Then, it is longitudinally focused by a cylindrical micro-convex lens array into 10 parallel linear spots, each 20mm long and 1mm wide. The overall dimensions (length*width*height) of the cylindrical concave lens array are 8*8*2mm, and the focal length is 30.63mm. Each cylindrical micro-convex lens in the array has dimensions (length*width) of 400*400μm, and they are arranged in a 16*16 array. Figures 2a-2b The diagram shows ten parallel linear pump beams formed after the laser passes through a cylindrical microlens array. Each linear spot represents a randomly generated spatial channel, and each spatial channel contains two channels: forward and backward. The energy density is greater than 0.5 mJ / cm². 2 The pump light irradiates the surface of the PDMS substrate onto which the dye solution is dropped, generating stimulated emission. This stimulated emission light is continuously scattered and amplified along the direction of the linear pump light, generating incoherent random laser light, which is emitted along the direction of the linear pump light. The incoherent random laser signals emitted from each channel are collected into a spectrometer using optical fibers.

[0042] The data post-processing system includes a spectrometer used to receive random laser data. The laser data is post-processed using fitting, high-order finite difference (HFD), and least significant bit (LSB) selection to generate a random number sequence. Specifically:

[0043] First, a fitting process is performed. Data points are selected from the incoherent random laser spectra collected by the spectrometer and fitted to obtain the theoretical incoherent random laser spectrum. After subtracting the smoothed incoherent random laser signal, a "hidden" coherent random laser spectral signal with noise-like characteristics is obtained. For example... Figure 3 The diagram shows a post-processing illustration of experimental data from this invention. The left image shows a typical incoherent random laser spectrum and the fitted incoherent random laser spectral lines. Subtracting the fitted smooth curve from the experimentally obtained spectrum yields the "hidden" coherent random laser spectrum shown in the right image. The points in the image represent data sampling points during post-processing.

[0044] Secondly, a sampling point is taken every four data points, resulting in 155 sampling points for each spectrum. Third-order difference calculations are then performed on these sampling points.

[0045]

[0046] Where m equals 3, n represents the interval between adjacent data points, and I represents the spectral intensity of the data point. Third-order difference calculation can effectively eliminate statistical bias in the sampling data.

[0047] Then, the values ​​of the sampled points are converted into binary. For each group of binary digits, four least significant bits are selected. Arranging this series of binary digits in sequence yields a random number sequence. The theoretical maximum sampling rate of this random number generator is 65.4 GHz. Therefore, the random number generation rate of this invention is 155 × 4 × 20 × 65.4 × 10⁹ = 810 Tbit / s, which is faster than all currently reported random number generators based on post-processing methods. Figure 4 The figure shows the highest sampling rate of this invention. Dynamic changes in random laser spectra within 100 picoseconds were acquired using a picosecond streak camera. The results show that there is no significant correlation between the "hidden" coherent random laser spectra generated every 15.29 ps, indicating that the highest sampling rate of this invention can reach 65.4 GHz.

[0048] The random number sequences generated by this invention were tested using the most authoritative and widely recognized NIST SP800-22 random number test standard. The results show that the random number sequences generated by this invention pass all tests and have practical application value. As shown in Table 1, the random number sequences generated by this random number generator were tested using the authoritative NIST SP800-22 random number standard, and the results show that the generated random number sequences pass all tests.

[0049] Table 1. Test results of 100 1Mbit data samples from NIST SP800-22

[0050]

[0051]

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A random laser based random number generator, characterized in that, include: Incoherent random laser source system and data post-processing system; The incoherent random laser source system includes an excitation source, a laser shaping mechanism, a PDMS substrate, and a dye solution dropped onto the surface of the PDMS substrate. The excitation source is used to output a pump laser, and the laser shaping mechanism is used to receive the pump laser and process it before irradiating the PDMS substrate. The processed pump laser uses the dye solution dropped onto the surface of the PDMS substrate as a gain medium to generate random laser. The laser shaping mechanism includes a cylindrical concave lens and a cylindrical microconvex lens array. The data post-processing system includes a spectrometer, which receives random laser light and performs post-processing on the laser data by fitting, high-order finite difference, and selecting the least significant bit, thereby generating a random number sequence. Fitting random laser light includes: The incoherent random laser spectrum collected by the spectrometer is fitted to obtain the theoretical incoherent random laser spectrum. Then, the theoretical incoherent random laser spectrum is subtracted from the incoherent random laser spectrum to obtain the hidden coherent random laser spectrum signal.

2. The random number generator based on random laser according to claim 1, characterized in that, The upper surface of the PDMS substrate has a grooved microstructure.

3. A random laser based random number generator according to claim 2, characterized in that, The PDMS substrate was prepared by the following method: A silica gel solution and a crosslinking agent were mixed in a ratio of 10:1 and placed in a vacuum chamber for 90 minutes to remove air bubbles, thus obtaining a PDMS solution. The PDMS solution is poured onto the inner surface of the abalone shell, filling the groove structure on the inner surface of the abalone shell. The PDMS layer was cured at 80°C for 180 minutes and then peeled off from the inner surface of the abalone shell to form a negative template. A 30 nm thick HfO2 film was coated on the grooved surface of the negative template by atomic layer deposition to form an anti-adhesion layer, thus completing the first PDMS replication. A second PDMS replication was performed on the negative template, and the PDMS substrate required for the experiment was successfully prepared.

4. The random laser based random number generator of claim 1, wherein, The pump laser is processed by the laser shaping mechanism, including: After the pump laser is laterally expanded by a cylindrical concave lens, it is irradiated onto the cylindrical microconvex lens array. A linear spot is formed by longitudinally focusing the expanded laser beam using a cylindrical micro-convex lens array, wherein the cylindrical micro-convex lens array consists of 16 lenses. A square array consisting of 16 cylindrical micro-convex lenses.

5. A random number generator based on random laser according to claim 1, characterized in that, The dye solution is a 1 mM Rhodamine 640 dye solution, and the solvent is ethanol.

6. The random laser based random number generator of claim 1, wherein, High-order finite difference finite difference analysis is performed on the hidden coherent random laser spectral signal, including: A third-order difference calculation is performed on the sampling points with equal wavelength intervals in the hidden coherent random laser spectrum, i.e. Where m equals 3, n represents the interval between adjacent data points, and I represents the spectral intensity of the data points, thus obtaining the light intensity sequence after eliminating statistical bias.

7. A random laser based random number generator according to claim 6, characterized in that, The light intensity sequence after statistical bias elimination is converted to binary, and then 4 least significant bits are selected to generate a random number sequence.

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