A method for reading and writing blue light information

Abstract

The blue light information reading and writing method provided by the present application uses a high power density blue light laser to excite an optical storage medium to perform two-photon information writing, and uses a low power density blue light laser to excite an optical storage medium to perform single-photon information reading, wherein the optical storage medium includes Pr 3+ The doped energy storage fluorescent material and the blue light information reading and writing method provided in this application overcome the limitation problem that many materials require high-energy photons for information writing, and avoid the complex memory structure problem caused by the traditional need for two lasers to cooperate to achieve optical information reading and writing.

Description

Technical Field

[0001] The present application relates to the technical field of optical information reading and writing, and in particular to a method for reading and writing blue light information. Background Art

[0002] At present, we have entered the era of "big data". One of the main problems faced in this era is the storage of massive amounts of information. Traditional storage technologies (such as solid-state drives, flash memory, and optical disks (two-dimensional planar storage modes limited by the optical diffraction limit) are already overwhelmed. In this era, the development of new storage technologies has become an important research direction. In recent years, optical information storage technology based on energy storage phosphors has attracted widespread attention due to its low power consumption, long life, small size, and multiple storage dimensions (large capacity). This optical storage method mainly consists of three steps: (1) using high-energy photons to excite the electrons in the ground state of the material to an ionized state, and then the electrons enter the traps of the material - information writing; (2) the electrons entering the traps are bound by the traps - information storage; (3) using low-energy photons to re-excite the electrons stored in the traps to an ionized state, and then migrate to the luminescence center to emit characteristic light signals - information reading.

[0003] For step (1), most optical storage materials (e.g., LiGa5O8:Mn 2+ 、Ca4Ti3O 10 :Pr 3+ ,Y 3+ 、Y2GeO5:Pr 3 + etc.) ultraviolet light is used as the light source for writing information, and some materials even require high-energy rays (such as NaYF4:Ln 3+ @NaYF4,Ln 3 + Indicates trivalent lanthanide ions, LiLuSiO4:Ce 3+ ,Tm 3+ etc.). Due to the high price of ultraviolet lasers and the safety issues of high-energy rays, many materials are still only in the laboratory stage and cannot be put into actual use. At present, blue lasers have been successfully commercialized and are cheap. If the energy of the light source for writing information can be reduced to the emission band of commercial blue lasers, it will facilitate the practical use of this optical storage technology. For step (3), the writing and reading of information requires two lasers of different wavelengths to cooperate with each other, which makes the structure of the optical storage device complicated and increases the cost. However, there is currently no solution that can solve the above two technical bottlenecks at the same time.

[0004] Therefore, while maintaining the original advantages of energy storage phosphor optical information storage technology, solving the problems existing in the above-mentioned optical information reading and writing process has become an urgent requirement for this optical storage technology. Summary of the Invention

[0005] In view of this, it is necessary to provide a blue light information reading and writing method that can simultaneously solve the problems of excessively high information writing photon energy and complex optical storage device structure in order to address the defects in the prior art.

[0006] To solve the above problems, this application adopts the following technical solutions:

[0007] One of the purposes of this application is to provide a method for reading and writing Blu-ray information, comprising the following steps:

[0008] Use high-power-density blue lasers to excite optical storage media for two-photon information writing;

[0009] Use low-power-density blue lasers to excite optical storage media for single-photon information reading;

[0010] Wherein, the optical storage medium includes Pr 3+ Doped energy storage fluorescent materials.

[0011] In some embodiments, in the step of exciting the optical storage medium with a high-power-density blue laser to perform two-photon information writing, the high-power-density is greater than or equal to the excitation threshold power density of up-conversion luminescence.

[0012] In some embodiments, in the step of exciting the optical storage medium with a low power density blue laser to perform single-photon information reading, the low power density is less than the excitation threshold power density of up-conversion luminescence.

[0013] In some embodiments, the high-power-density blue laser and the low-power-density blue laser are emitted by the same laser.

[0014] In some embodiments, the power density is changed by changing the laser current or voltage.

[0015] In some embodiments, the wavelength of the blue laser is 440-490 nm.

[0016] In some embodiments, the characteristic light signal of the blue laser information reading is Pr 3+ 4f 1 5d 1 →4f 2 The transition.

[0017] In some embodiments, the Pr 3+ Doped energy storage fluorescent materials have 4f 1 5d 1 of the launch.

[0018] In some embodiments, the Pr 3+ The preparation method of the doped energy storage fluorescent material is as follows:

[0019] Y2O3、Pr6O 11 After mixing and grinding Eu2O3, Al2O3 and Ga2O3, the obtained mixture is sintered at 1200℃-1500℃ in air atmosphere for 3-10 hours, and then cooled to room temperature naturally to obtain the Pr 3+ Doped energy storage fluorescent materials.

[0020] This application adopts the above technical solution, and its beneficial effects are as follows:

[0021] The blue light information reading and writing method provided by the present application uses a high power density blue light laser to excite an optical storage medium to perform two-photon information writing, and uses a low power density blue light laser to excite an optical storage medium to perform single-photon information reading, wherein the optical storage medium includes Pr 3+ The doped energy storage fluorescent material and the blue light information reading and writing method provided in this application overcome the limitation problem that many materials require high-energy photons for information writing, and avoid the complex memory structure problem caused by the traditional need for two lasers to cooperate to achieve optical information reading and writing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 The design of Example 1 of this application utilizes Pr 3+ Schematic diagram of the energy level structure doped into the matrix to achieve two-photon information writing with a high-power-density blue laser and single-photon information reading with a low-power-density blue laser;

[0024] Figure 2 The present invention is Example 1 in YAGG:Pr 3+ ,Eu 3+ Pr in optical storage media 3+ (a) Excitation spectrum and (b) emission spectrum of

[0025] Figure 3 The Pr in Example 1 of the present application at different excitation power densities 3+ (a) Upconversion emission spectrum and (b) relationship between excitation power density and upconversion luminescence intensity.

[0026] Figure 4 In Example 1 of the present application, after writing information with a 450nm blue laser, the Pr 3+ 4f 1 5d 1 →4f 2 (300nm) thermoluminescence curve measured by the transition.

[0027] Figure 5 Example 1 of the present application is 500mW / cm 2 After the blue laser writes the information, it uses 20mW / cm 2 Blue laser pulses read information. DETAILED DESCRIPTION

[0028] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0029] In the description of this application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0030] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0031] In order to make the purpose, technical solutions and advantages of this application more clear, this application is further described in detail below with reference to the accompanying drawings and embodiments.

[0032] This embodiment provides a method for reading and writing blue light information, comprising the following steps: using a high-power-density blue light laser to excite an optical storage medium to perform two-photon information writing; using a low-power-density blue light laser to excite an optical storage medium to perform single-photon information reading; wherein the optical storage medium comprises Pr 3+ Doped energy storage fluorescent materials.

[0033] In some embodiments, in the step of exciting the optical storage medium with a high-power-density blue laser to perform two-photon information writing, the high-power-density is greater than or equal to the excitation threshold power density of up-conversion luminescence.

[0034] It is understandable that when the power density of the blue laser exceeds Pr 3+ When the upconversion threshold is reached, ground-state electrons can absorb two blue light photons and be excited to a high-energy delocalized state. These electrons can be captured by traps in the material, enabling information writing. When the excitation power density is lower than the upconversion threshold, information writing cannot be performed.

[0035] In some embodiments, in the step of exciting the optical storage medium with a low power density blue laser to perform single-photon information reading, the low power density is less than the excitation threshold power density of up-conversion luminescence.

[0036] It can be understood that when electrons are already stored in the trap, the electrons can be excited out of the trap by using a blue laser with a power density lower than the upconversion threshold, and the 4f 1 5d 1 The light information is emitted, and the light information is the characteristic light signal for information reading.

[0037] It should be noted that the Pr 3+ It can simultaneously ensure that the luminescent ion has an energy level structure for up-conversion, can lose electrons, and has the characteristics of radiation transition at the high energy level. For example, Tm 3+ It has a suitable energy level structure and emission energy level, but cannot lose electrons, so it cannot be used for this information reading and writing method; Mn 2+ and Cr 3+ Even with a suitable energy level structure, electrons can be lost, but the high energy level cannot emit characteristic light signals, so it cannot be used in this information reading and writing method. In addition, after writing information with high power density, if the information is read using a power density greater than the upconversion threshold, upconversion luminescence will occur, interfering with the characteristic light signal, resulting in signal errors, which does not meet the requirements of the present invention. Therefore, the information reading and writing method of this application must be strictly in accordance with Pr 3+ The threshold of up-conversion is used to divide the power density of information writing and reading. In addition, as an optical storage material, it is necessary to ensure that the Pr 3+ After the information is written, the storage phosphor will not release electrons due to thermal ionization at room temperature (afterglow phenomenon). 3+ The phosphor does not meet the requirements of the present invention.

[0038] In some embodiments, the high-power-density blue laser and the low-power-density blue laser are emitted by the same laser, and the power density is changed by changing the laser current or voltage.

[0039] It can be understood that the present application uses the same blue laser (only the difference in laser power density) to read and write information, so it can overcome the structural complexity problem caused by the traditional need for two lasers to cooperate to achieve information reading and writing.

[0040] In some embodiments, the wavelength of the blue laser is 440-490 nm.

[0041] It can be understood that the design of the above information reading and writing method of this application reduces the energy of information writing photons to the emission wavelength of commercial blue light lasers, avoiding the use of expensive ultraviolet light sources and dangerous high-energy rays, which is conducive to the practical application of this type of optical storage technology.

[0042] In some embodiments, the characteristic light signal of the blue laser information reading is Pr 3+ 4f 1 5d 1 →4f 2 The transition.

[0043] In some embodiments, the Pr 3+ The preparation method of the doped energy storage fluorescent material is as follows:

[0044] Y2O3、Pr6O 11 After mixing and grinding Eu2O3, Al2O3 and Ga2O3, the obtained mixture is sintered at 1200℃-1500℃ in air atmosphere for 3-10 hours, and then cooled to room temperature naturally to obtain the Pr 3+ Doped energy storage fluorescent materials.

[0045] This application uses Pr 3+3 P 0,1,2 and 1 The I6 energy level (440-490nm) matches the emission wavelength of commercial blue lasers, and Pr 3+ With the function of losing electrons, a new information reading and writing method was designed, which uses high-power density blue laser for two-photon information writing and low-power blue laser for single-photon information reading. It overcomes the limitation that many materials require high-energy photons for information writing, and avoids the complex memory structure problem caused by the traditional need for two lasers to cooperate to realize optical information reading and writing.

[0046] The above technical solutions of the present application are described in detail below with reference to specific embodiments.

[0047] Synthetic Pr-doped3+ Optical storage media: (Y 0.999 Pr 0.0005 Eu 0.0005 )3(Al 0.4 Ga 0.6 )5O 12 (abbreviated as YAGG:Pr 3+ ,Eu 3+ ) is prepared as follows: According to the chemical composition: 2.997Y2O3-0.0005Pr6O 11 -0.0015Eu2O3-2Al2O3-3Ga2O3 stoichiometric ratio of Y2O3, Pr6O 11 , Eu2O3, Al2O3 and Ga2O3, after being fully mixed and ground, the resulting mixture was pressed into a grinding tool with a length, width and thickness of 5cm and 1mm, and then sintered at 1500℃ in air atmosphere for 3 hours. After naturally cooling to room temperature, YAGG:Pr 3+ , Eu 3+ Optical storage medium. The sintering temperature can be selected in the range of 1200℃-1500℃, and the sintering time can be selected in the range of 3-8 hours. It should be emphasized that the above materials are listed only to demonstrate the feasibility of a blue light information reading and writing method of the present invention, and do not limit the information reading and writing method of the present invention to be only applicable to YAGG:Pr 3+ , Eu 3+ In optical storage media. Under the premise of meeting the claims, many Pr 3+ The doped energy storage type phosphor can be used to read and write information using the method of the present invention.

[0048] Figure 1 It is designed to use Pr 3+ The energy level structure doped into the matrix realizes the principle diagram of using high-power blue laser to write information and low-power blue laser to read information. 3+ When the ground state electron absorbs a blue light photon, it jumps to 3 P J (J=0,1,2) and 1 I6 state, these electrons can absorb a blue light photon to enter a higher ionization state. The ionized electrons are captured by traps in the material through process ① (information writing). The electrons captured by the deep traps are bound for a long time (process ②, information storage). When a beam of low-power density blue laser is used to stimulate the electrons in the trap, these electrons can absorb a blue light photon and be re-stimulated to the ionization state (Optically-Stimulated Luminescence, OSL), and then migrate to Pr 3+ 4f 1 5d 1The state realizes transition and emits characteristic light signals (process ③, information reading).

[0049] YAGG:Pr 3+ , Eu 3+ As an information storage medium, the feasibility and innovation of the present invention are further illustrated. Figure 2 (a) Given Pr 3+ The excitation spectrum of Pr 3+ The energy level structure of the blue laser. 440-490nm is the emission band of commercial blue laser and Pr 3+ of 3 P J (J=0,1,2) and 1 The I6 energy level matches well, and any of these energy levels can be excited to up-convert luminescence. Due to the special electronic structure of rare earth elements, the wavelengths corresponding to these energy levels are different in Pr 3+ The doped optical storage medium remains substantially unchanged, therefore, the wavelength of the blue laser in the present invention is 440-490 nm. Figure 2 (b) Pr 3+ The emission spectrum shows obvious 4f 1 5d 1 It has the ability to emit characteristic light signals when information is read.

[0050] 450nm blue laser was used as the excitation light to measure Pr 3+ Up-conversion luminescence, such as Figure 3 (a) shows the relationship between the upconversion luminescence intensity and the excitation power density. Figure 3 (b). When the excitation power density is lower than 40mW / cm 2 When there is no up-conversion luminescence; greater than or equal to 40mW / cm 2 When the excitation power density and luminous intensity show a nearly quadratic functional relationship I∝P 1.76 , indicating the occurrence of the two-photon upconversion process, and also proving that the upconversion threshold in this material is 40mW / cm 2 The power density is 500mW / cm 2 After exciting the storage medium with a 450nm blue laser (writing information), the emission at 300nm (4f 1 5d 1 →4f 2 ), the measured thermoluminescence curve is as follows Figure 4 This result shows that using a blue laser with a power greater than the upconversion threshold can store electrons in a trap through a two-photon upconversion process, thus achieving information writing.

[0051] Figure 5 It is 500mW / cm2 After writing information with a 450nm blue laser (greater than the upconversion threshold), the 2 The 450nm blue laser (less than the up-conversion threshold) is used for pulsed information reading (light-stimulated luminescence). The above-mentioned blue lasers with different power densities are the same laser, and the power density is changed by adjusting the current or voltage. 3+ 4f 1 5d 1 To 4f 2 Characteristic light signal of transition (300nm). "1" means turning on 20mW / cm 2 The 450nm blue laser is used, and "0" means off. When not reading, no characteristic light signal appears, indicating that the information is stably stored and there is no signal loss; when reading, an obvious characteristic light signal is displayed, and it can be read repeatedly. Obviously, the present invention realizes the use of a high-power density blue laser for two-photon information writing and the use of the same laser with low power density for information reading. The information reading and writing method of the present invention overcomes the limitation problem that many materials require high-energy photons for information writing; at the same time, it overcomes the problem of complex memory structure caused by the need for two lasers to cooperate in order to realize information reading and writing in traditional information reading and writing schemes.

[0052] It can be understood that the various technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above are merely preferred embodiments of the present application and only specifically describe the technical principles of the present application. These descriptions are intended only to explain the principles of the present application and should not be construed in any way as limiting the scope of protection of the present application. Based on the explanations herein, any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application, as well as other specific implementations of the present application that can be conceived by those skilled in the art without inventive effort, shall be included within the scope of protection of the present application.

Claims

1. A method for reading and writing blue light information, characterized in that: The steps include: Using a high-power-density blue laser to excite an optical storage medium for two-photon information writing, wherein the high-power-density is greater than or equal to the excitation threshold power density of up-conversion luminescence; Using a low-power-density blue laser to excite the optical storage medium for single-photon information reading, wherein the low-power-density is less than the excitation threshold power density of up-conversion luminescence; Wherein, the optical storage medium includes Pr 3+ Doped energy storage fluorescent materials.

2. The method for reading and writing Blu-ray information according to claim 1, wherein: The high-power-density blue laser and the low-power-density blue laser are emitted by the same laser.

3. The method for reading and writing Blu-ray information according to claim 2, wherein: The power density is varied by changing the laser current or voltage.

4. The method for reading and writing Blu-ray information according to claim 1, wherein: The wavelength of the blue laser is 440-490 nm.

5. The method for reading and writing Blu-ray information according to claim 1, wherein: The characteristic light signal of the information reading of the blue laser is Pr 3+ 4f 1 5d 1 →4f 2 The transition.

6. The method for reading and writing Blu-ray information according to claim 5, wherein: The Pr 3+ Doped energy storage fluorescent materials have 4f 1 5d 1 of the launch.

7. The method for reading and writing Blu-ray information according to claim 6, wherein: The Pr 3+ The preparation method of the doped energy storage fluorescent material is as follows: Y2O3、Pr6O 11 After mixing and grinding Eu2O3, Al2O3 and Ga2O3, the obtained mixture is sintered at 1200℃-1500℃ in air atmosphere for 3-10 hours, and then cooled to room temperature naturally to obtain the Pr 3+ Doped energy storage fluorescent materials.

Images