A random laser based on a porous biomaterial and a preparation method thereof

Abstract

The application discloses a random laser prepared based on a porous biological material and a preparation method thereof, and comprises the following steps: S1, cleaning a coral base material; S2, drying treatment; S3, vacuum degassing treatment; S4, preparing a dyeing solution; S5, coral block immersion dyeing; and S6, dye curing, and the random laser with the porous biological material as the base is prepared through the preparation method, and the whole process steps from cutting, cleaning, pretreatment and dyeing of the coral base material to dye curing are formed, the boundaries of each process are clear, process parameter calibration and repeated tests are facilitated, a standardization preparation scheme can be formed, the preparation technology vacancy of the natural coral base random laser is filled, and the preparation method can effectively clean the coral pores and remove the gas in the pores, the distribution density of the effective gain medium in the coral is improved, the overlapping degree of the light field and the gain substance is increased, a lower laser threshold is beneficial to be obtained, and the environment-friendly random laser with low threshold and stable performance is prepared.

Description

Technical Field

[0001] This invention relates to the field of random laser technology, and more specifically to a random laser based on porous biomaterials and its fabrication method. Background Technology

[0002] Compared to traditional lasers, random lasers do not require a resonant cavity structure. They achieve laser output solely through a pump source and a gain medium, possessing unique advantages such as low coherence, high emission energy, and narrow full width at half maximum (FWHM). They hold broad application prospects in optical sensing, precision detection, and other fields. The core criterion for judging random laser performance is the change in radiation mechanism. When the pump energy reaches a critical threshold, the device's emission changes from amplified spontaneous emission to stimulated emission. The emission spectrum rapidly narrows from a broad spectrum, the FWHM is significantly compressed, and the lasing intensity is greatly increased. Threshold performance is a key indicator for evaluating the performance of random lasers.

[0003] Currently, most random lasers are fabricated using artificially synthesized materials. While these materials can achieve basic lasing functions, they suffer from drawbacks such as poor biocompatibility and non-biodegradability, making them unsuitable for the green and low-carbon industrial development trend and limiting the widespread application of random laser technology in green scenarios such as biomedicine and marine environmental monitoring. With the rapid development of green photonics, developing biocompatible, biodegradable, and environmentally friendly natural optical materials, and fabricating low-threshold, stable, and environmentally friendly random lasers, has become a research hotspot and a key area for technological breakthroughs in this field.

[0004] Natural marine biomaterials possess inherent biodegradability and biocompatibility, making them ideal substrates for fabricating green optoelectronic devices and a key research area in current green photonics. The tropical waters of Hainan, my country, boast abundant and unique marine biological resources, among which corals possess special naturally porous microstructures and biomineralized structures, along with excellent optical transmittance. Their natural structural advantages are significant, making them well-suited for the fabrication of laser devices.

[0005] However, although natural coral materials possess natural structural and optical advantages suitable for random laser devices, the industry currently lacks mature technical means to prepare random lasers using coral, especially lacking core technologies and preparation schemes for developing low-threshold, stable, and environmentally friendly random lasers based on natural coral substrates.

[0006] Existing research has failed to fully exploit the optical structural advantages of natural corals, leaving a technological gap in "using coral substrates to prepare high-performance, green, and biodegradable random lasers." Therefore, there is an urgent need for an environmentally friendly random laser that utilizes porous corals as a substrate to create a laser with both low threshold performance and stable performance. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of the aforementioned technologies by proposing a random laser based on porous biomaterials and its fabrication method, thereby solving the problems described above.

[0008] This invention provides a method for fabricating a random laser based on porous biomaterials, comprising the following steps: S1, Coral substrate cleaning: Rinse the coral raw material and cut it into large pieces of coral. Rinse the large pieces of coral again with deionized water. Then cut the large pieces of coral into smaller pieces of coral. Clean the coral pieces with deionized water and anhydrous ethanol in turn. S2, Drying treatment: The cleaned coral pieces are dried. S3, Vacuum degassing treatment: The coral block is placed in a negative pressure environment to eliminate trace amounts of air in its internal pores; S4, Preparation of staining solution: The staining solution is prepared using PM597 powder, toluene solution and liquid crystal material.

[0009] S5, Coral block immersion and staining: Use the staining solution prepared in step S4 to immerse and stain the coral blocks. S6, Dye curing: The dyed coral blocks are placed in containers and dried to obtain random laser samples.

[0010] Preferably, in step S1, the operation of cleaning the coral blocks with deionized water and anhydrous ethanol is as follows: Operation (1): Place the coral block in a beaker and pour in deionized water to submerge the coral block. Place the entire beaker in an ultrasonic cleaner and continuously clean it with ultrasonic vibration for 5-10 minutes. Operation (2): Place the coral block after cleaning with deionized water into a new beaker, pour in anhydrous ethanol to submerge the coral block, and place the beaker in an ultrasonic cleaner for continuous ultrasonic oscillation cleaning for 5 to 10 minutes.

[0011] Preferably, in step S1, the operation of cleaning the coral blocks with deionized water and anhydrous ethanol is repeated multiple times, including operation (1) and operation (2).

[0012] Preferably, the drying process in step S2 is as follows: Place coral blocks in a petri dish and let them stand in a fume hood for 30 minutes to drain the anhydrous ethanol from the surface. Then place them in a vacuum drying oven and dry them at a constant temperature of 40~45℃ and a gauge pressure of -0.055~-0.065MPa for 2 hours.

[0013] Preferably, the coral blocks that have undergone drying treatment in step S2 are subjected to vacuum degassing in step S3 as follows: The culture dish containing the coral blocks was placed in a vacuum drying oven. The temperature was adjusted to 20-25℃ and kept at a constant temperature for 45-60 minutes under a gauge pressure of -0.08 to -0.095 MPa.

[0014] Preferably, after the vacuum degassing in step S3 is completed, the pressure inside the vacuum drying oven is controlled to slowly rise back to atmospheric pressure.

[0015] Preferably, the dyeing operation on the coral block in step S5 is as follows: Pour the staining solution obtained in step S4 into the container holding the coral blocks, and immerse the coral blocks completely. Let it stand for 2-3 hours.

[0016] Preferably, the drying process in step S6 is as follows: After the coral blocks have been dyed in step S5, remove them and place them on a petri dish to stand for 5-10 minutes. Then place them in a vacuum drying oven and dry them for 30 minutes at 35-40℃ and a gauge pressure of -0.06 to -0.07 MPa. After drying, slowly release the pressure to normal pressure and then remove the petri dish to complete the curing process after the coral blocks have been dyed.

[0017] Preferably, step S4, preparing the staining solution, is as follows: Weigh the PM597 dye powder and dissolve it in toluene solution to obtain a 10 mg / ml PM597-toluene solution; The liquid crystal material was added to the prepared PM597-toluene solution at a mass ratio of 1:10 to PM597 dye and mixed thoroughly.

[0018] Based on the same inventive concept as the above embodiments, the present invention also provides a random laser prepared by a method for preparing a random laser based on porous biomaterials.

[0019] Compared with the prior art, the present invention has at least the following beneficial effects: Random lasers based on coral, a porous biomaterial, are prepared using a process involving cleaning, drying, vacuum degassing, dyeing solution preparation, coral block immersion dyeing, and dye curing. This process forms a complete workflow from coral substrate cutting, cleaning, pretreatment, dyeing to dye curing, with clear boundaries between each step, facilitating process parameter calibration and repeated testing. This results in a standardized and feasible preparation scheme, enabling the preparation of stable random lasers using coral and filling the gap in complete preparation technology for natural coral-based random lasers. Furthermore, this preparation method is optimized for the porous structure of coral, effectively cleaning coral pores and removing gas from within them, increasing the distribution density of the effective gain medium inside the coral, and increasing the overlap between the light field and the gain material. This is beneficial for obtaining a lower laser threshold, resulting in an environmentally friendly random laser that combines low threshold performance with stable performance. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The emission spectra of the Comparative Example 2 sample (PM597 / capillary) at different pump energies are shown. Figure 2 The graph shows the emission intensity and FWHM of the sample in Comparative Example 2 (PM597 / capillary) as a function of pump energy. Figure 3 The emission spectra of Comparative Example 1 sample (PM597 / coral) at different pump energies are shown. Figure 4 The emission spectra of Comparative Example 3 sample (PM597+LC / capillary) at different pump energies are shown. Figure 5 The graph shows the emission intensity and FWHM of the comparative sample (PM597+LC / capillary) as a function of pump energy. Figure 6 The emission spectra of the sample (PM597+LC / coral) in Example 1 at different pump energies are shown below. Figure 7 The graph shows the change in emission intensity of the sample in Comparative Example 1 and the sample in Example 1 as the pump energy increases. Figure 8 A schematic diagram illustrating the experimental principle for each sample; Figure 9(a) is a schematic diagram of the structure of the undyed coral block in the beaker; Figure 9(b) is a schematic diagram of the sample (PM597 / coral) in Comparative Example 1; Figure 10(a) is a schematic diagram of the comparative example 3 sample (PM597+LC / capillary); Figure 10(b) is a schematic diagram of the sample (PM597+LC / coral) in Example 1; Figure 11 This is a flowchart of a method for preparing a random laser based on porous biomaterials in one embodiment of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. In the following description, the expression "some embodiments" describes a subset of all possible embodiments; however, it should be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0023] It should also be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "inner," "outer," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0024] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0025] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0026] Example 1 (using coral substrate, PM597 + toluene as dye; i.e., PM597 + LC / coral): This invention provides a method for fabricating a random laser based on porous biomaterials, comprising: S1, Coral substrate cleaning: Rinse the coral raw material and cut it into large pieces of coral with a diameter of 9~11cm. Rinse the large pieces of coral again with deionized water. Then cut the large pieces of coral into coral blocks with a diameter of 2cm. Clean the coral blocks with deionized water and anhydrous ethanol in turn. S2, Drying treatment: The cleaned coral pieces are dried. S3, Vacuum degassing treatment: The coral block is placed in a negative pressure environment to eliminate trace amounts of air in its internal pores; S4, Preparation of dyeing solution: Weigh PM597 dye powder and dissolve it in toluene solution to obtain a 10 mg / ml PM597-toluene solution; S5, Coral block immersion and staining: Use the staining solution prepared in step S4 to immerse and stain the coral blocks. S6, Dye curing: The dyed coral blocks are placed in containers and dried to obtain random laser samples.

[0027] Random lasers based on coral, a porous biomaterial, are prepared using a process involving cleaning, drying, vacuum degassing, dyeing solution preparation, coral block immersion dyeing, and dye curing. This process forms a complete workflow from coral substrate cutting, cleaning, pretreatment, dyeing to dye curing, with clear boundaries between each step, facilitating process parameter calibration and repeated testing. This results in a standardized and feasible preparation scheme, enabling the preparation of stable random lasers using coral and filling the gap in complete preparation technology for natural coral-based random lasers. Furthermore, this preparation method is optimized for the porous structure of coral, effectively cleaning coral pores and removing gas from within them, increasing the distribution density of the effective gain medium inside the coral, and increasing the overlap between the light field and the gain material. This is beneficial for obtaining a lower laser threshold, resulting in an environmentally friendly random laser that combines low threshold performance with stable performance.

[0028] Specifically, in step S1, the procedure of cleaning the coral blocks with deionized water and anhydrous ethanol is as follows: Operation (1): Place the coral block in a beaker and pour in deionized water to submerge the coral block. Place the entire beaker in an ultrasonic cleaner and continuously clean it with ultrasonic vibration for 5-10 minutes. Operation (2): Place the coral block after cleaning with deionized water into a new beaker, pour in anhydrous ethanol to submerge the coral block, and place the beaker in an ultrasonic cleaner for continuous ultrasonic oscillation cleaning for 5 to 10 minutes.

[0029] Furthermore, in step S1, the operation of cleaning the coral blocks with deionized water and anhydrous ethanol is repeated multiple times, including operation (1) and operation (2).

[0030] The coral blocks are ultrasonically cleaned sequentially with deionized water and anhydrous ethanol, which can effectively remove surface oil, dust and residual impurities in the pores. After cleaning, they are dried at low temperature to ensure that the coral channels are completely clean and unobstructed.

[0031] Specifically, the drying process in step S2 is as follows: Place coral blocks in a petri dish and let them stand in a fume hood for 20 minutes to drain the anhydrous ethanol from the surface. Then place them in a vacuum drying oven and dry them at a constant temperature of 40~45℃ and a gauge pressure of -0.055~-0.065MPa for 2 hours.

[0032] After cleaning the coral blocks, if they are placed directly into a drying chamber, the large amount of liquid ethanol on the surface will evaporate rapidly under negative pressure, forming a high concentration of ethanol vapor in the chamber within a short time. This easily reaches the saturation pressure, inhibiting the diffusion of ethanol from the pores and leading to a phenomenon of dry exterior and wet interior. However, placing the coral blocks in a fume hood can effectively remove wastewater ethanol and deionized water from the surface, avoiding this phenomenon. In addition, a vacuum environment can remove anhydrous ethanol from the pores at a lower temperature. Without continuous circulating airflow washing over the loose coral matrix, it avoids the wear and breakage of the porous structure of the coral surface caused by high-speed airflow impact. It also prevents the rapid evaporation of surface solvent from causing pore drying and sealing, and the retention of internal solvent, resulting in a dry exterior and wet interior. This reduces the capillary stress induced by the violent evaporation of solvent, which can lead to micropore collapse and blockage of connecting channels, thus minimizing the preservation of the coral's original three-dimensional interconnected porous scattering framework. This ensures uniform wetting of the PM597 dye and is beneficial for obtaining stable random laser samples.

[0033] Furthermore, the coral blocks that have undergone drying treatment in step S2 are subjected to vacuum degassing in step S3 as follows: The culture dish containing the coral blocks was placed in a vacuum drying oven. The temperature was adjusted to 20-25℃ and kept at a constant temperature for 45-60 minutes under a gauge pressure of -0.08 to -0.095 MPa.

[0034] Vacuum degassing can effectively remove trace amounts of air trapped inside the pores of coral blocks, preventing air bubbles in the micropores from hindering the penetration of the staining solution into the deeper layers of the skeleton during atmospheric pressure immersion, thus preventing only surface staining. At the same time, it reduces optical scattering loss caused by the gas-liquid interface in the pores, which is conducive to promoting full staining of the coral block pores, effectively improving the spatial overlap between the gain medium and the random light field, helping to reduce the random laser threshold and improve the stability of the sample's luminescence performance.

[0035] Furthermore, after the vacuum degassing in step S3 is completed, the pressure inside the vacuum drying oven is controlled to slowly rise back to atmospheric pressure.

[0036] After the vacuum degassing process is completed, the pressure inside the control chamber is slowly restored to atmospheric pressure. This allows the pressure difference between the inside and outside of the coral pores to gradually reach equilibrium, preventing the airflow impact and instantaneous pressure difference caused by rapid depressurization from damaging the loose porous skeleton, preventing micropore collapse and surface structure damage, and preserving the coral's interconnected scattering channels intact. At the same time, it avoids the trapping of air bubbles in the pores due to sudden pressure changes, reduces dyeing voids and ensures uniform loading of gain dyes, which is beneficial for the preparation of stable coral-based random laser devices.

[0037] The back pressure parameter is controlled by the control panel on the vacuum drying oven, and the working status of each valve is also controlled. For example, during the back pressure process of gauge pressure -0.08~-0.095MPa, the valve opening is controlled according to the input back pressure duration to adjust the air intake. The overall back pressure duration is required to be greater than 2 minutes.

[0038] Specifically, the dyeing process for the coral blocks in step S5 is as follows: Pour the staining solution obtained in step S4 into the container holding the coral blocks, and immerse the coral blocks completely. Let it stand for 2-3 hours.

[0039] During the dyeing stage, the dyeing solution is completely immersed in the coral block and kept immersed for 2-3 hours to ensure that the gain dye is in full contact with the porous skeleton of the coral block.

[0040] Furthermore, the drying process in step S6 is as follows: After the coral blocks have been dyed in step S5, remove them and place them on a petri dish to stand for 5-10 minutes. Then place them in a vacuum drying oven and dry them for 30 minutes at 35-40℃ and a gauge pressure of -0.06 to -0.07 MPa. After drying, slowly release the pressure to normal pressure and then remove the petri dish to complete the curing process after the coral blocks have been dyed.

[0041] After staining, place the coral blocks in a petri dish and let them stand for 5–10 minutes. This allows the free staining solution to drip naturally from the sample surface, preventing large amounts of liquid toluene from directly entering the vacuum drying oven and avoiding rapid evaporation of the surface solvent that could cause excessive dye precipitation and accumulation at the well openings. Subsequently, the sample is dried at 35–40 °C under gauge pressure. 0.06~ Vacuum drying and curing at 0.07 MPa reduces the thermal degradation of PM597 dye under low-temperature negative pressure, while simultaneously removing toluene solvent from the pores smoothly, avoiding pore sealing and microporous structure damage caused by normal-pressure hot air drying. After drying, slow gradient depressurization gradually balances the pressure inside and outside the coral pores, preventing instantaneous pressure shocks from damaging the loose porous substrate. The entire curing process ensures stable adsorption and fixation of PM597 dye inside the coral channels, reducing dye surface aggregation and concentration quenching, and ensuring uniform spatial distribution of the gain medium. This is beneficial for preparing coral-based random lasers with low threshold and stable output performance.

[0042] Specifically, step S4, preparing the staining solution, is as follows: Weigh the PM597 dye powder and dissolve it in toluene solution to obtain a 10 mg / ml PM597-toluene solution; The liquid crystal material was added to the prepared PM597-toluene solution at a mass ratio of 1:10 to PM597 dye and mixed thoroughly.

[0043] Comparative Example 1 (coral substrate, PM597 + toluene as dye; i.e., PM597 / coral): Prepare a 10 mg / ml PM597-toluene solution as the staining solution. Then, immerse the coral block in the staining solution, ensuring that the solution completely wets the coral block. After staining, the sample preparation is complete.

[0044] Comparative Example 2 (capillary, PM597 + toluene; i.e., PM597 / capillary): Prepare a 10 mg / ml PM597-toluene solution as the staining solution. Then, utilize capillary action to draw the staining solution into the capillary tube.

[0045] Comparative Example 3 (capillary, PM597 + toluene + liquid crystal; i.e., PM597 + LC / capillary): Prepare a 10 mg / ml PM597-toluene solution and add liquid crystal material at a mass ratio of 1:10 for PM597 dye to liquid crystal material. Mix the liquid crystal material with the above PM597-toluene solution to prepare a dyeing solution. Then, use the capillary action of a capillary tube to draw the dyeing solution into the capillary tube.

[0046] It should be noted that the liquid crystal material used in the above embodiments and comparative examples is BHR40300 nematic liquid crystal (Cp=81.30℃) produced by Beijing Bayi Space-Time Liquid Crystal Technology Co., Ltd. (n=0.250).

[0047] In addition, the experimental instruments used in this application are listed in the table below:

[0048] The experimental principles for each sample are as follows: Figure 8 As shown, it should be noted that the use of a laser to emit laser light onto the sample and the acquisition of the corresponding pump energy and spectral information such as emission profile, peak wavelength, full width at half maximum (FWHM), and laser spike by an energy meter and a spectrometer are technical contents known to those skilled in the art and will not be described in detail in this application.

[0049] Performance Analysis: like Figure 1The emission spectra of the sample in Comparative Example 2 (PM597 / capillary) at different pump energies are shown in the figure. It can be clearly observed that with increasing pump energy, many peaks appear, ranging from 570 nm to 600 nm. The number of peaks within this range also continuously increases, indicating a process from spontaneous fluorescence emission to random lasing. In the figure, when the pump energy is 36.6 μJ, the emission intensity of the emission spectrum is very low, showing only a broad fluorescence spectrum. As the pump energy increases, when it exceeds 45.6 μJ, the emission energy of the emission spectrum suddenly increases, with multiple obvious peaks appearing around 580 nm. Further increasing the pump energy results in an increasing number of peaks and a greater emission intensity. This is related to the multiple scattering of light in the undispersed dye molecules. In a certain multiple scattering path, when the gain exceeds the loss, random lasing is triggered.

[0050] like Figure 2 The emission intensity and FWHM of the sample (PM597 / capillary) as a function of pump energy are shown in the figure. A clear threshold behavior is observed. As shown, when the pump energy is 25 μJ, the full width at half maximum (FWHM) of the sample emission spectrum is approximately 20 nm; when the pump energy is 36.6 μJ, the FWHM is approximately 17 nm, which is clearly a fluorescence spectrum of dye emission. When the pump energy is 41.8 μJ, the FWHM is approximately 6 nm, which is obviously related to the spontaneous emission amplification of dye molecules under high pump energy excitation. However, as the pump energy continues to increase, at 45.6 μJ, the FWHM of the sample emission spectrum suddenly decreases to less than 1 nm (approximately 0.5 nm). With increasing pump energy, the intensity of the sample emission spectrum also gradually increases. When the pump energy is 45.6 μJ, a sudden change in emission energy occurs (generating random laser oscillations, satisfying the characteristics of random laser oscillation), and its threshold is at 45.6 μJ.

[0051] like Figure 3 The emission spectra of Comparative Example 1 sample (PM597 / coral) at different pump energies are shown in the figure. It can be seen from the figure that when the pump energy is 27.2 μJ, the emission intensity is very low, and only fluorescence can be observed. As the pump energy increases, the intensity of the emission spectrum gradually increases. When it reaches 43.0 μJ, the emission intensity of the sample increases sharply. Further increasing the pump energy results in a significant narrowing of the full width at half maximum (FWHM) of the sample's emission spectrum, which is due to the spontaneous emission amplification phenomenon of the dye molecules within the sample.

[0052] contrast Figure 1 and Figure 3It can be seen that when the same dye dispersion is immersed in a capillary glass tube and a coral structure respectively, the random laser light appearing in the capillary glass tube is transformed into spontaneous emission amplification in the coral structure. This phenomenon indicates that the coral structure has a large number of pores, resulting in stronger localization of light and greater light loss. This acts as a mode selection mechanism, transforming the multi-layered random laser light into a single-layered spontaneous emission amplification.

[0053] like Figure 4 The emission spectra of the comparative example 3 sample (PM597+LC / capillary) at different pump energies are shown. When the pump energy is 16.7 μJ, the emission intensity of the emission spectrum is very low, and the sample can only emit fluorescence. As the pump energy increases, the full width at half maximum (FWHM) of the emission spectrum gradually decreases. When the pump energy increases to 25.9 μJ, multiple sharp peaks with a FWHM of less than 1 nm appear on the emission spectrum, indicating that there is obvious random laser generation (photons undergo multiple random scattering in the gain medium inside the capillary, and disordered scattering constructs an optical resonance path. When the optical gain in the scattering path exceeds the total loss of the system, random laser oscillation output is generated), and its threshold is 25.9 μJ.

[0054] like Figure 5 The emission intensity and FWHM of Comparative Example 3 (PM597+LC / capillary) as a function of pump energy are shown in the figure. When the pump energy is 16.7 μJ, its FWHM is about 17 nm. However, as the pump energy increases, the emission intensity of the sample suddenly increases at 25.9 μJ, while the FWHM narrows to 0.4 nm. This threshold (25.9 μJ) behavior once again verifies that the random lasing is induced by multiple scattering inside Comparative Example 3 (PM597+LC / capillary).

[0055] like Figure 6 The emission spectra of sample 1 (PM597+LC / coral) at different pump energies are shown in the figure. As the pump energy gradually increases, the emission spectrum of the sample undergoes a process from fluorescence to spontaneous emission. When the pump energy is greater than 24.0 μJ, the full width at half maximum (FWHM) of the emission spectrum suddenly narrows. Until the pump energy increases to 34.2 μJ, a single very sharp peak appears on the sample emission spectrum, located at approximately 590 nm. Figure 6 This can be viewed as a process from fluorescence to amplified spontaneous emission to the appearance of random single-film lasers.

[0056] Figure 6 and Figure 4 The comparison shows that after immersing the PM597+LC mixture in capillary glass tubes and coral structures respectively, the emission spectra changed from multimode random lasers to single-mode random lasers, further verifying the modulating effect of coral structures on random laser modes. Through observation... Figure 6It can be seen that as the pump energy increases, the peak position of the emission spectrum remains relatively stable, all around 590 nm, indicating the stability of coral in modulating random laser modes.

[0057] like Figure 7 The graph shows the intensity changes of emission from Comparative Example 1 and Example 1 samples as pump energy increases. The green curve corresponding to Comparative Example 1 is a relatively flat, approximately linearly increasing straight line. In this case, the coral skeleton, acting as a scattering center, can provide some scattering feedback, but it may not be sufficient to form a large number of effective random laser closed loops. Therefore, as the pump energy increases, the main emission mechanism is amplified spontaneous emission (ASE) or strong fluorescence. The intensity of spontaneous emission is quasi-linearly related to the pump energy, without a very steep inflection point.

[0058] The sample in Example 1 corresponds to the red curve. This curve shows a slow increase in emission intensity at low pump energies, with a distinct inflection point at approximately 20-30 μJ, after which the emission intensity exhibits a very steep linear increase. The red threshold inflection point is the hallmark of random lasing. Below the threshold, the system is dominated by fluorescence and spontaneous emission. Once the pump energy exceeds the threshold, the scattering feedback intensity is sufficient to overcome the losses, and random lasing begins, leading to a sharp increase in emission intensity. When liquid crystal is combined with the coral framework, it can greatly enhance the disorder and scattering ability of the system, significantly increasing the probability of forming a photonic localized closed loop, thereby reducing the energy required to generate lasing (i.e., lowering the threshold).

[0059] Performance comparison results: 1. Based on the performance analysis, the sample of Comparative Example 1 (PM597 / capillary) was compared with the sample of Example 1 (PM597+LC / coral), and the sample of Comparative Example 2 (PM597 / capillary) was compared with the sample of Comparative Example 3 (PM597+LC / capillary). It can be seen that the liquid crystal composite system effectively reduces the random laser oscillation threshold.

[0060] By introducing liquid crystal materials, the scattering and coupling characteristics of the system were optimized, successfully achieving random laser oscillation. The liquid crystal component improved the dispersion of the gain medium and enhanced disordered photon scattering, improved the localization effect of the optical field, and reduced the pump energy required for random laser oscillation.

[0061] 2. Based on the performance analysis, compared with the Comparative Example 3 sample (PM597+LC / capillary), the Example 1 sample (PM597+LC / coral) can achieve single-mode random laser output and has mode control capability.

[0062] Compared to the multimode random laser of the Comparative Example 3 sample (PM597+LC / capillary), the optical loss caused by the porous interface after the gain medium system was filled into the three-dimensional porous framework of the coral exerted a mode-selection effect, modulating the multimode random laser into a single-mode random laser output. This is beneficial for obtaining a spectrally pure emission signal without intense mode competition. Furthermore, under different pump energy excitations, the emission peak remained stably maintained around 590 nm, confirming that the coral framework can stably constrain the gain and liquid crystal composition, achieving stable random laser output wavelength and suppressing mode jumps.

[0063] 3. Based on the performance analysis, comparing Example 1 with Comparative Example 3, and comparing Comparative Example 1 with Comparative Example 2, it can be seen that the three-dimensional porous substrate of natural coral can play a mode screening role, which can modulate multimode random laser into single-mode random laser, and obtain a more stable emission signal. At the same time, PM597 and liquid crystal composite gain medium are immobilized in solid porous framework, which effectively overcomes the defect of poor stability of capillary liquid phase system. Furthermore, natural coral relies on its own original pores to provide a disordered scattering network, eliminating the need for microfabrication to prepare cavities. The process route is green and environmentally friendly, and is suitable for the preparation of stable solid-state narrowband environmentally friendly random lasers.

[0064] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of the present invention without departing from the scope of the present invention are within the protection scope of the present invention.

Claims

1. A method for fabricating a random laser based on porous biomaterials, characterized in that, Includes the following steps: S1, Coral substrate cleaning: Rinse the coral raw material and cut it into large pieces of coral. Rinse the large pieces of coral again with deionized water. Then cut the large pieces of coral into smaller pieces of coral. Clean the coral pieces with deionized water and anhydrous ethanol in turn. S2, Drying treatment: The cleaned coral pieces are dried. S3, Vacuum degassing treatment: The coral block is placed in a negative pressure environment to eliminate trace amounts of air in its internal pores; S4, Preparation of staining solution: The staining solution is prepared using PM597 powder, toluene solution and liquid crystal material. S5, Coral block immersion and staining: Use the staining solution prepared in step S4 to immerse and stain the coral blocks. S6, Dye curing: The dyed coral blocks are placed in containers and dried to obtain random laser samples.

2. The method for fabricating a random laser based on porous biomaterials according to claim 1, characterized in that, In step S1, the procedure for cleaning the coral blocks with deionized water and anhydrous ethanol is as follows: Operation (1): Place the coral block in a beaker and pour in deionized water to submerge the coral block. Place the entire beaker in an ultrasonic cleaner and continuously clean it with ultrasonic vibration for 5-10 minutes. Operation (2): Place the coral block after cleaning with deionized water into a new beaker, pour in anhydrous ethanol to submerge the coral block, and place the beaker in an ultrasonic cleaner for continuous ultrasonic oscillation cleaning for 5 to 10 minutes.

3. The method for fabricating a random laser based on porous biomaterials according to claim 2, characterized in that, In step S1, the operation of cleaning the coral blocks with deionized water and anhydrous ethanol is repeated multiple times, including operation (1) and operation (2).

4. The method for fabricating a random laser based on porous biomaterials according to claim 1, characterized in that, The drying process in step S2 is as follows: Place coral blocks in a petri dish and let them stand in a fume hood for 30 minutes to drain the anhydrous ethanol from the surface. Then place them in a vacuum drying oven and dry them at a constant temperature of 40~45℃ and a gauge pressure of -0.055~-0.065MPa for 2 hours.

5. The method for fabricating a random laser based on porous biomaterials according to claim 4, characterized in that, The coral blocks that have undergone drying in step S2 will be subjected to vacuum degassing in step S3 as follows: The culture dish containing the coral blocks was placed in a vacuum drying oven. The temperature was adjusted to 20-25℃ and kept at a constant temperature for 45-60 minutes under a gauge pressure of -0.08 to -0.095 MPa.

6. The method for fabricating a random laser based on porous biomaterials according to claim 5, characterized in that, After the vacuum degassing in step S3 is completed, the pressure inside the vacuum drying oven is controlled to slowly rise back to atmospheric pressure.

7. The method for fabricating a random laser based on porous biomaterials according to claim 1, characterized in that, The dyeing process for the coral blocks in step S5 is as follows: Pour the staining solution obtained in step S4 into the container holding the coral blocks, and immerse the coral blocks completely. Let it stand for 2-3 hours.

8. The method for fabricating a random laser based on porous biomaterials according to claim 1, characterized in that, The drying process in step S6 is as follows: After the coral blocks have been dyed in step S5, remove them and place them on a petri dish to stand for 5-10 minutes. Then place them in a vacuum drying oven and dry them for 30 minutes at 35-40℃ and a gauge pressure of -0.06 to -0.07 MPa. After drying, slowly release the pressure to normal pressure and then remove the petri dish to complete the curing process after the coral blocks have been dyed.

9. The method for fabricating a random laser based on porous biomaterials according to claim 1, characterized in that, Step S4 involves preparing the staining solution as follows: Weigh the PM597 dye powder and dissolve it in toluene solution to obtain a 10 mg / ml PM597-toluene solution; The liquid crystal material was added to the prepared PM597-toluene solution at a mass ratio of 1:10 to PM597 dye and mixed thoroughly.

10. A random laser prepared according to any one of claims 1 to 9 using a method for preparing a random laser based on porous biomaterials.

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