Data storage method and data storage system

Abstract

A data storage method and a data storage system. The method is used to store data in an optical storage medium, the optical storage medium comprising a glass substrate and rare earth ions doped in the glass substrate. The method comprises: generating a pulsed laser by a pulsed laser; and focusing the pulsed laser into the glass substrate, the pulsed laser being used to change the ion valence state of the irradiated rare earth ions in the glass substrate from a first ion valence state to a second ion valence state, thereby realizing data writing, wherein the optical storage medium is an optical storage medium irradiated by ultraviolet light, each rare earth ion is in the first ion valence state or the second ion valence state, the first ion valence state is used to indicate the first data, and the second ion valence state is used to indicate the second data. The method can greatly improve the signal-to-noise ratio of the optical storage medium, thereby realizing smaller-sized recording point reading and improving the data storage capacity of the optical storage medium.

Description

Technical Field

[0001] Embodiments of the present disclosure generally relate to the field of storage technology, and more particularly, to a data storage method and a data storage system for an optical storage medium. Background Art

[0002] With the continuous innovation and rapid development of technologies such as the Internet, Internet of Things, cloud computing, and artificial intelligence, human society has entered the era of big data. The data generated in today's society is growing at a very fast rate. According to the forecast of the Internet Data Center (IDC), the total amount of global data may reach 175ZB by 2025, which will bring extremely high requirements for data storage capacity.

[0003] Improving data storage capacity can be achieved by reducing the size of storage units, increasing the number of storage layers, or increasing the amount of information carried by a single storage unit (i.e., multi-dimensional storage). Optical storage technology has the advantages of high storage density, long storage life, strong stability, fast read and write speed, and low cost. Therefore, it has obvious advantages in high-density storage compared with other conventional storage technologies (such as semiconductor memory technology and magnetic storage technology).

[0004] Optical storage technology mainly includes two parts: data writing and data reading. Data writing uses laser to irradiate optical storage media. The interaction between laser and media causes the properties of the media to change and store information. Data reading uses laser to scan the media and identify changes in the properties of the storage unit. The signal-to-noise ratio is a key factor affecting data reading accuracy, and it also determines the size of the read signal, thus directly affecting the data storage capacity. Especially in high-density optical storage, when the size of the storage unit to be written has reached the diffraction limit, how to accurately read the nanometer-level signal becomes a key issue that limits the storage capacity. Therefore, the signal-to-noise ratio directly determines the accuracy of signal reading of optical storage media. Summary of the invention

[0005] The embodiments of the present disclosure provide a data storage method and a data storage system, which are intended to solve the above-mentioned problems and other potential problems existing in conventional data storage solutions for optical storage media.

[0006] According to one aspect of the present disclosure, a data storage method is provided, the method being used to store data in an optical storage medium, the optical storage medium comprising a glass substrate and rare earth ions doped in the glass substrate, the method comprising: generating a pulsed laser by a pulsed laser; and focusing the pulsed laser into the glass substrate, the pulsed laser being used to transform the ionic valence state of the irradiated rare earth ions in the glass substrate from a first ionic valence state to a second ionic valence state, thereby achieving data writing, wherein the optical storage medium is an optical storage medium irradiated by ultraviolet light, each rare earth ion is in the first ionic valence state or the second ionic valence state, the first ionic valence state is used to indicate first data, and the second ionic valence state is used to indicate second data.

[0007] According to the embodiments of the present disclosure, the background noise in the glass substrate can be reduced by using an optical storage medium irradiated with ultraviolet light. In addition, the valence state of the rare earth ions in the glass substrate can be changed by using a pulsed laser to irradiate the rare earth ions, thereby realizing data writing. In this way, compared with the traditional optical storage technology, the data storage method according to the embodiments of the present disclosure can greatly improve the signal-to-noise ratio of the optical storage medium, so that weaker fluorescent signals can be read, and smaller recording points can be read, thereby improving the accuracy of data storage and increasing the data storage capacity of the optical storage medium.

[0008] In some embodiments, the rare earth ions include europium (Eu) ions, and the first ion valence state of the europium ions is Eu. 3+ , and the second ion valence state of the europium ion is Eu 2+ .

[0009] In some embodiments, the rare earth ions include samarium (Sm) ions, and the first ion valence state of the samarium ions is Sm 3+ , and the second ion valence state of the samarium ion is Sm 2+ .

[0010] In some embodiments, the data storage method further includes: irradiating the glass substrate with ultraviolet light, wherein the proportion of rare earth ions in the first ionic valence state in the glass substrate after irradiation with the ultraviolet light is higher than the proportion of rare earth ions in the second ionic valence state.

[0011] In some embodiments, the ultraviolet light includes a single light spot, and irradiating the glass substrate with the ultraviolet light includes: scanning the glass substrate with the single light spot.

[0012] In some embodiments, the ultraviolet light includes a divergent light spot, and irradiating the glass substrate with the ultraviolet light includes: irradiating the glass substrate with the divergent light spot for a predetermined time.

[0013] In some embodiments, the wavelength of the ultraviolet light is in the range of 200 nm to 400 nm.

[0014] In some embodiments, the wavelength of the ultraviolet light is 375 nm.

[0015] In some embodiments, the data storage method further includes: irradiating the glass substrate with a continuous laser; and detecting the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state in the glass substrate, thereby realizing reading of data stored in the optical storage medium.

[0016] In some embodiments, the wavelength of the continuous laser is in the range of 400 nm to 500 nm.

[0017] In some embodiments, the wavelength of the continuous laser comprises 405 nm or 488 nm.

[0018] In some embodiments, the intensity of the fluorescent light is detected using a photomultiplier tube or an avalanche photodiode.

[0019] In some embodiments, the pulsed laser is in the visible light or infrared band.

[0020] In some embodiments, the central wavelength of the pulsed laser comprises 800 nm or 1030 nm.

[0021] In some embodiments, the pulse width of the pulse laser includes femtosecond or picosecond order.

[0022] In some embodiments, the pulse width of the pulse laser is 220 fs.

[0023] In some embodiments, the repetition frequency of the pulsed laser is in the range of kHz to hundreds of MHz.

[0024] In some embodiments, the repetition frequency of the pulsed laser is 1 KHz.

[0025] In some embodiments, the energy of a single pulse of the pulsed laser is in the range of nanojoules to millijoules.

[0026] In some embodiments, the single pulse energy of the pulse laser is 0.5 μJ.

[0027] In some embodiments, the data storage method further includes: controlling the pulse laser to be focused on different positions in the glass substrate to change the ion valence states of different rare earth ions in the glass substrate.

[0028] According to another aspect of the present disclosure, a data storage system is provided, the data storage system comprising: an optical storage medium for storing data, the optical storage medium comprising a glass substrate and rare earth ions doped in the glass substrate, the optical storage medium being an optical storage medium irradiated by ultraviolet light, each rare earth ion being in a first ionic valence state or a second ionic valence state, the first ionic valence state being used to indicate first data, and the second ionic valence state being used to indicate second data; a pulsed laser configured to generate a pulsed laser; and a laser guiding unit configured to focus the pulsed laser into the glass substrate, the pulsed laser being used to transform the ionic valence state of the irradiated rare earth ions in the glass substrate from the first ionic valence state to the second ionic valence state, thereby achieving data writing.

[0029] In some embodiments, the rare earth ions include europium (Eu) ions, and the first ion valence state of the europium ions is Eu. 3+ , and the second ion valence state of the europium ion is Eu 2+ .

[0030] In some embodiments, the rare earth ions include samarium (Sm) ions, and the first ion valence state of the samarium ions is Sm 3+ , and the second ion valence state of the samarium ion is Sm 2+ .

[0031] In some embodiments, the data storage system further includes: an ultraviolet light source configured to irradiate the glass substrate with ultraviolet light, wherein the proportion of rare earth ions in the first ionic valence state in the glass substrate after irradiation with the ultraviolet light is higher than the proportion of rare earth ions in the second ionic valence state.

[0032] In some embodiments, the wavelength of the ultraviolet light is in the range of 200 nm to 400 nm.

[0033] In some embodiments, the wavelength of the ultraviolet light is 375 nm.

[0034] In some embodiments, the data storage system also includes: a continuous laser configured to irradiate the glass substrate with continuous laser; and a detector configured to detect the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state in the glass substrate, thereby enabling reading of data stored in the optical storage medium.

[0035] In some embodiments, the wavelength of the continuous laser is in the range of 400 nm to 500 nm.

[0036] In some embodiments, the wavelength of the continuous laser comprises 405 nm or 488 nm.

[0037] In some embodiments, the detector comprises a photomultiplier tube or an avalanche photodiode.

[0038] In some embodiments, the pulsed laser is in the visible light or infrared band.

[0039] In some embodiments, the central wavelength of the pulsed laser comprises 800 nm or 1030 nm.

[0040] In some embodiments, the pulse width of the pulse laser includes femtosecond or picosecond order.

[0041] In some embodiments, the pulse width of the pulse laser is 220 fs.

[0042] In some embodiments, the repetition frequency of the pulsed laser is in the range of kHz to hundreds of MHz.

[0043] In some embodiments, the energy of a single pulse of the pulsed laser is in the range of nanojoules to millijoules.

[0044] In some embodiments, the single pulse energy of the pulse laser is 0.5 μJ.

[0045] In some embodiments, the data storage system further includes: a position adjustment unit configured to control the laser guiding unit to focus the pulse laser to different positions in the glass substrate to change the ion valence states of different rare earth ions in the glass substrate.

[0046] In a third aspect, a computer storage medium is provided, such as a non-transitory computer readable storage medium, on which a computer program (or instruction) is stored, and when the computer program (or instruction) is executed on a data read / write control device, the data storage system can be controlled to execute the data storage method provided in the first aspect and any one of the embodiments of the first aspect.

[0047] In a fourth aspect, the present application provides a computer program product, which, when running on a data storage system, can control the data storage system to execute the data storage method in the first aspect and any possible embodiment thereof.

[0048] This summary is provided to introduce a selection of concepts in a simplified form, which are further described in the detailed description below. This summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The above and other objects, features and advantages of the embodiments of the present disclosure will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present disclosure are shown by way of example and not limitation.

[0050] Figure 1 An architectural diagram of an optical storage system is shown in which the data storage method according to an embodiment of the present disclosure can be applied.

[0051] Figure 2 A flow chart of a data storage method according to an embodiment of the present disclosure is shown.

[0052] Figure 3 A comparison of the floor noise measured for an unirradiated optical storage medium and the floor noise measured for an irradiated optical storage medium is shown.

[0053] Figure 4 A comparison of the background fluorescence intensity measured for a non-irradiated optical storage medium and the background fluorescence intensity measured for an irradiated optical storage medium at different excitation powers is shown.

[0054] Figure 5 A comparison of a Raman spectrum measured for a non-irradiated optical storage medium and a Raman spectrum measured for an irradiated optical storage medium is shown.

[0055] Figure 6 A comparison of the absorption spectrum measured for a non-irradiated optical storage medium and the absorption spectrum measured for an irradiated optical storage medium is shown.

[0056] Figure 7 Optical microscope images of a non-irradiated optical storage medium and an irradiated optical storage medium are shown.

[0057] Figure 8 Graphs of the fluorescence signals of a non-irradiated optical storage medium and an irradiated optical storage medium are shown.

[0058] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0060] The term "including" and its variations used in this document represent open inclusion, that is, "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one other embodiment". Terms such as "upper", "lower", "front", and "rear" indicating placement or positional relationships are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the principles of the present disclosure, and do not indicate or imply that the referred elements must have a specific orientation, be constructed or operate in a specific orientation, and therefore should not be understood as limitations on the present disclosure.

[0061] As described above, the signal-to-noise ratio is a key factor affecting data reading accuracy, and also determines the size of the read signal, thus directly affecting the data storage capacity. Especially in high-density optical storage, when the size of the storage unit to be written has reached the diffraction limit, how to accurately read the nanometer-level signal becomes a key issue limiting the storage capacity. Therefore, the signal-to-noise ratio directly determines the accuracy of the signal reading of the optical storage medium.

[0062] A conventional solution to improve the signal-to-noise ratio of data read from optical storage media is to use a phase-locked amplifier (also called a phase detector) to process the read signal. The phase-locked amplifier can separate a specific carrier frequency signal from an environment with extremely high interference (for example, the signal-to-noise ratio can be as low as -60dB or even lower), thereby obtaining signal amplitude and phase information. The phase-locked amplifier uses a heterodyne oscillation technology, which converts the measured signal into a direct current by frequency conversion. That is, by using the signal correlation principle in the phase-locked amplifier, after multiplying and integrating two periodic signals mixed with noise, the signal is detected from the noise, and the purpose of weakening the influence of noise through cross-correlation operation is achieved. The phase-locked measurement method can extract the signal within a specified frequency band centered on the reference frequency and effectively filter out all other frequency components. However, using a phase-locked amplifier to process the signal read from the optical storage medium is a passive method to improve the signal-to-noise ratio, which neither fundamentally increases the signal strength nor reduces the background noise of the optical storage medium.

[0063] The embodiments of the present disclosure provide a data storage method for an optical storage medium to reduce background noise in the optical storage medium, thereby improving the signal-to-noise ratio when reading data. Figures 1 to 8 Detailed description according to the principles of the present disclosure.

[0064] Figure 1 FIG. 2 shows an architecture diagram of an optical storage system in which the data storage method according to an embodiment of the present disclosure can be applied. Figure 1As shown, the optical storage system 100 includes an optical disc 11 for storing data, a read / write optical path module 12 for performing read / write operations on the optical disc 11, and other modules for controlling the read / write operations and performing corresponding processing.

[0065] During the data writing process, after receiving the data to be written via the interface module 19, the codec module 14 encodes the data and stores the encoded data in the cache. Subsequently, the main control module 16 sends a servo control signal to the servo control module 18, thereby servo-controlling the read-write optical path module 12 through the servo control module 18 and the servo electromechanical system 17. In addition, the main control module 16 sends an optical path control signal to the optical path control module 15, thereby controlling the optical path of the read-write optical path module 12. Finally, the read-write optical path module 12 writes the data into the optical disc 11 under the control of the servo electromechanical system 17 and the optical path control module 15, completing the data writing work.

[0066] During the data reading process, the detector in the read / write optical path module 12 collects the feedback optical signal on the optical disc 11 and detects the data signal and the servo signal respectively. The data signal is processed by the signal processing module 13 and stored in the cache. Subsequently, the codec module 14 decodes the data to complete the data reading work.

[0067] Embodiments of the present disclosure provide an optical storage medium with a high signal-to-noise ratio, which can be used as Figure 1 The embodiment of the present disclosure also provides a method for reading data from an optical storage medium, which can be Figure 1 The embodiment of the present disclosure also provides a data storage system, which includes an optical storage medium according to an embodiment of the present disclosure and a device for performing a read and write operation on the optical storage medium (eg Figure 1 The read-write optical path module 12 shown in FIG.

[0068] In an embodiment according to the present disclosure, an optical storage medium includes a glass substrate and rare earth ions doped in the glass substrate, such as europium (Eu) ions, samarium (Sm) ions or other rare earth ions. Each rare earth ion can be in a first ionic valence state or a second ionic valence state, for indicating different data respectively. For example, the first ionic valence state can be used to indicate first data, and the second ionic valence state can be used to indicate second data. Through the excitation of a pulsed laser, the rare earth ions in the first ionic valence state in the glass substrate can be converted into the second ionic valence state, while the rare earth ions in the second ionic valence state will remain unchanged. Therefore, through the excitation of a pulsed laser, data can be written into the optical storage medium to achieve single pulse writing. When a continuous laser is used to irradiate the glass substrate, the rare earth ions in the first ionic valence state and the rare earth ions in the second ionic valence state will present different fluorescence states. For example, the rare earth ions in the first ionic valence state can basically not emit fluorescence or only emit a darker fluorescence, while the rare earth ions in the second ionic valence state will emit a stronger fluorescence. Therefore, by detecting the intensity of the fluorescence emitted by the rare earth ions in the second ion valence state, the data in the optical storage medium can be read.

[0069] In some embodiments, the first data is binary data 0, and the second data is binary data 1. In other embodiments, the first data is binary data 1, and the second data is binary data 0. In other embodiments, the first data and the second data may also be other types of data, and the scope of the present disclosure is not limited in this respect.

[0070] The principle of the present disclosure will be described below using europium ions as an example. It should be understood that the principles and operations described for europium ions are also applicable to other rare earth ions, and will not be described in detail herein for other rare earth ions.

[0071] The first ion valence state of europium ion is Eu 3+ , used to indicate the first data, and the second ion valence state of the europium ion is Eu 2+ , used to indicate the second data. When writing data to the optical storage medium, Eu 3+ Ions can be transformed into Eu 2+ When reading data from an optical storage medium, a continuous laser is used to irradiate the glass substrate. 3+ Ions and Eu 2+ The ions will exhibit different fluorescent states. Specifically, Eu 3+ ions will emit a fainter fluorescence, while Eu 2+ ions will emit strong fluorescence. 2+ The intensity of the fluorescence emitted by the ions can be used to read the data in the optical storage medium.

[0072] For Eu 3+ Ion-doped glass can be prepared by conventional high-temperature melting methods. The raw materials of the glass may include Eu 2 O 3 、Na 2 O、Al 2 O 3 and B 2 O 3 , the ratio can be 0.1Eu in molar ratio 2 O 3 -10Na 2 O-5Al 2 O 3 -85B 2 O 3 After the prepared glass is cut and optically polished, a glass sample with a desired thickness (e.g., 2 mm or other thickness) is made and used as an optical storage medium. It should be understood that in other embodiments, the method, other raw materials, or other raw material ratios may be used to prepare glass, and the scope of the present disclosure is not limited in this respect.

[0073] During the glass firing process, due to the high temperature field, some Eu 3+ The ions are reduced to Eu 2+ ions, so that the glass substrate contains Eu 2+ When a continuous laser is used to irradiate a glass substrate for data reading, Eu ions are generated during the glass firing process. 2+ The ions also emit fluorescence, which affects the detector's ability to detect Eu2O3, which is stored in the optical storage medium. 2+ The accuracy of identifying the fluorescence emitted by ions. In other words, the Eu generated during the glass firing process 2+ Ions bring noise, which makes the signal-to-noise ratio of the optical storage medium lower when reading data, thereby affecting the accuracy of data reading. The embodiments of the present disclosure provide a method for eliminating or at least partially alleviating such noise. 3+ After the ion-doped glass is fired, the glass can be pre-treated, that is, the glass substrate is irradiated with high-power density ultraviolet light. The proportion of rare earth ions in the first ionic valence state in the glass substrate irradiated with ultraviolet light is higher than the proportion of rare earth ions in the second ionic valence state. The inventors found that after the glass substrate is irradiated with ultraviolet light, the signal-to-noise ratio of the optical storage medium is significantly improved. This is because the Eu generated during the glass firing process can be irradiated with ultraviolet light. 2+ The ion is reoxidized to Eu 3+ ions, thereby reducing the Eu in the glass substrate 2+The content of ions.

[0074] In some embodiments, a single light spot can be emitted by an ultraviolet light source, and the light spot can be used to scan the glass substrate, thereby irradiating the entire glass substrate. For example, an ultraviolet light source can be used to emit ultraviolet light of a predetermined wavelength at a predetermined power density. For example, the power density of the ultraviolet light source can be 0.5-1.5 KW / cm 2 , such as 1KW / cm 2 . The wavelength of the ultraviolet light can be in the range of 200nm to 400nm, for example, 375nm. It should be understood that the power density of the ultraviolet light source and the wavelength of the ultraviolet light can be selected according to the design requirements of the optical storage medium, and the scope of the present disclosure is not limited in this respect. In other embodiments, an ultraviolet light source can be used to emit a divergent light spot, and the divergent light spot can be used to irradiate the glass substrate for a predetermined time, thereby achieving irradiation of the entire glass substrate. It should be understood that in the embodiments according to the present disclosure, the glass substrate can also be irradiated with ultraviolet light in other ways, which can also eliminate or at least partially eliminate the Eu generated during the glass firing process. 2+ The ion is reoxidized to Eu 3+ ion.

[0075] The following will be combined Figure 2 The data storage method for the optical storage medium according to the embodiment of the present disclosure is described. The optical storage medium used here is an optical storage medium that has been subjected to ultraviolet light irradiation as described above. Figure 2 As shown, in step S210, a pulse laser is generated by a pulse laser; and in step S220, the pulse laser is focused into the glass substrate to irradiate the rare earth ions in the glass substrate. In this way, the ion valence state of the irradiated rare earth ions in the glass substrate can be changed from a first ion valence state to a second ion valence state. For example, in the case where the rare earth ions are europium ions, the irradiation of the pulse laser can make Eu 3+ Ions can be transformed into Eu 2+ When the rare earth ion is samarium ion, the irradiation of pulsed laser can make Sm 3+ ions can be transformed into Sm 2+ Ions. When the rare earth ions are other ions, similar ion valence changes can also be achieved. As described above, different ion valences of rare earth ions are used to indicate different data, so data writing to optical storage media can be achieved by changing the ion valence of rare earth ions. The ion valence of different rare earth ions in the glass substrate can be changed by controlling the pulse laser to be focused to different positions in the glass substrate, thereby achieving the writing of various data.

[0076] According to the embodiments of the present disclosure, the background noise in the glass substrate can be reduced by irradiating the optical storage medium with ultraviolet light, and the valence state of the rare earth ions in the glass substrate can be changed by irradiating the rare earth ions with pulsed laser, thereby realizing data writing. In this way, compared with the traditional optical storage technology, the data storage method according to the embodiments of the present disclosure can greatly improve the signal-to-noise ratio of the optical storage medium, so that weaker fluorescent signals can be read, and smaller recording points can be read, thereby improving the data storage capacity of the optical storage medium.

[0077] In some embodiments, the pulsed laser is in the visible light band, and the central wavelength of the pulsed laser may be in the range of 400nm to 700nm. In other embodiments, the pulsed laser is in the infrared band, and the central wavelength of the pulsed laser may be in the range of 800nm ​​to 1500nm, for example, 800nm ​​or 1030nm. In other embodiments, the pulsed laser may also be in other bands, and the scope of the present disclosure is not limited in this respect.

[0078] In some embodiments, the pulse width of the pulse laser is in the order of femtoseconds or picoseconds, for example, 220 fs. A pulse laser in the order of femtoseconds can irradiate rare earth ions in a glass substrate at high power, thereby achieving accurate writing of data. A pulse laser in the order of picoseconds can also irradiate rare earth ions in a glass substrate at a relatively high power, thereby achieving writing of data. In other embodiments, the pulse width of the pulse laser can also be other orders of magnitude, and the scope of the present disclosure is not limited in this respect.

[0079] In some embodiments, the repetition frequency of the pulsed laser is in the range of kHz to hundreds of MHz, for example, 1 kHz. In other embodiments, the repetition frequency of the pulsed laser can also be in other ranges, and the scope of the present disclosure is not limited in this respect.

[0080] In some embodiments, the energy of a single pulse of the pulsed laser is in the range of nanojoule to millijoule, for example, 0.5 μJ. In other embodiments, the energy of a single pulse of the pulsed laser can also be in other ranges, and the scope of the present disclosure is not limited in this respect.

[0081] Figure 3 A comparison of the base noise measured for an unirradiated optical storage medium and the base noise measured for an irradiated optical storage medium is shown, which is obtained by irradiating a glass substrate with a continuous laser and detecting the generated fluorescence. Figure 3As shown in FIG. 3 , region 301 indicates the base noise measured for the irradiated optical storage medium, and region 302 indicates the base noise measured for the unirradiated optical storage medium. It can be seen that when the continuous laser is used to irradiate the glass substrate, there is a strong background fluorescence in region 302, which indicates that there is a large amount of Eu in the unirradiated optical storage medium. 2+ ions, these Eu 2+ The ions are noise ions generated during the glass firing process. In contrast, the background fluorescence in region 302 becomes dark, which indicates that after the optical storage medium is irradiated with ultraviolet light, the Eu generated during the glass firing process 2+ The ions have been reoxidized to Eu by UV irradiation. 3+ When a continuous laser is used to irradiate a glass substrate for data reading, the Eu ions present in the unirradiated optical storage medium 2+ The background fluorescence emitted by the ions will affect the data reading accuracy, and the irradiated optical storage medium will 2+ The ion content is greatly reduced without affecting the data reading accuracy.

[0082] Figure 4 A comparison diagram of the background fluorescence intensity measured for an unirradiated optical storage medium and the background fluorescence intensity measured for an irradiated optical storage medium at different excitation powers is shown. Figure 4 As shown, curve 601 indicates the background fluorescence intensity measured for the unirradiated optical storage medium, and curve 602 indicates the background fluorescence intensity measured for the irradiated optical storage medium. It can be seen that under different excitation powers (i.e., under the irradiation of reading light of different intensities), the background fluorescence intensity of the optical storage medium irradiated with ultraviolet light (curve 602) is about 10 times lower than the background fluorescence intensity of the optical storage medium not irradiated with ultraviolet light (curve 601). Therefore, the embodiments of the present disclosure can improve the fluorescence signal-to-noise ratio by more than 10 times compared with the traditional optical storage technology by combining the ultraviolet light pretreatment process with the pulsed laser writing process, so that weaker fluorescence signals can be read, and smaller recording point reading can be achieved, thereby improving the data storage capacity of the optical storage medium.

[0083] Figure 5 1 shows a comparison of the Raman spectrum measured for an unirradiated optical storage medium and the Raman spectrum measured for an irradiated optical storage medium. Figure 5 As shown, curve 401 indicates the Raman spectrum measured for the unirradiated optical storage medium, and curve 402 indicates the Raman spectrum measured for the irradiated optical storage medium. It can be seen that, with the change of Raman shift, the Raman spectrum measured for the irradiated optical storage medium and the Raman spectrum measured for the unirradiated optical storage medium have basically the same curve shape, and the only difference is that the intensity of the Raman spectrum is different.

[0084] Figure 6 FIG. 4 shows a comparison of the absorption spectrum measured for an unirradiated optical storage medium and the absorption spectrum measured for an irradiated optical storage medium. Figure 6 As shown, curve 501 indicates the absorption spectrum measured for the unirradiated optical storage medium, and curve 502 indicates the absorption spectrum measured for the irradiated optical storage medium. It can be seen that, as the wavelength changes, the absorption spectrum measured for the irradiated optical storage medium and the absorption spectrum measured for the unirradiated optical storage medium have substantially the same curve shape, and the only difference is that the intensity of the absorption spectrum is different.

[0085] Combination Figure 5 and Figure 6 It can be seen that, through the performance structure test of the optical storage medium before and after irradiation, it was found that the pre-treatment process using ultraviolet light has no effect on the structure of the optical storage medium, and thus will not affect the writing and reading of data.

[0086] Figure 7 Optical microscope images of an unirradiated optical storage medium and an irradiated optical storage medium are shown, and the optical microscope images can reflect the change in the refractive index of the material. Figure 7 The left side of the figure shows an unirradiated optical storage medium, and the right side of the figure shows an irradiated optical storage medium. Part I and Part II respectively contain a plurality of points irradiated with pulsed laser and having data written thereon, such as the points that have been converted into Eu by the irradiation of the pulsed laser. 2+ The point where the europium ion is located in the valence state. Figure 7 It can be seen that there is no obvious difference in the optical microscope images of the unirradiated optical storage medium and the irradiated optical storage medium, which shows that the pretreatment process using ultraviolet light has no effect on the structure of the optical storage medium.

[0087] Figure 8 The fluorescence signal diagram of the unirradiated optical storage medium and the irradiated optical storage medium is shown. Figure 8 The left side of the figure shows an unirradiated optical storage medium, and the right side of the figure shows an irradiated optical storage medium. Part I and Part II respectively contain a plurality of points irradiated with pulsed laser and having data written thereon, such as the points that have been converted into Eu by the irradiation of the pulsed laser. 2+The point where the europium ion in the valence state is located. As shown in Part I, the background fluorescence of the unirradiated optical storage medium is brighter, and the intensity of the background fluorescence is somewhat close to the fluorescence intensity of the point where data has been written, and the background fluorescence may mask the fluorescence of the point where data has been written. As shown in Part II, the background fluorescence of the irradiated optical storage medium is darker, and the contrast between the intensity of the background fluorescence and the fluorescence intensity of the point where data has been written is very obvious. Therefore, when continuous laser irradiation is used for data reading, the irradiated optical storage medium can provide a significantly improved signal-to-noise ratio. Compared with traditional optical storage technology, the fluorescence signal-to-noise ratio can be increased by more than 10 times, so that weaker fluorescence signals can be read, and smaller recording points can be read, thereby increasing the data storage capacity of the optical storage medium.

[0088] In some embodiments, the data storage method further includes: irradiating a glass substrate with a continuous laser; and detecting the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state in the glass substrate, thereby realizing the reading of data stored in the optical storage medium. When the glass substrate is irradiated with a continuous laser, the rare earth ions in the first ionic valence state and the rare earth ions in the second ionic valence state in the glass substrate will present different fluorescence states. For example, the rare earth ions in the first ionic valence state will basically not emit fluorescence or emit a dimmer fluorescence, while the rare earth ions in the second ionic valence state will emit a stronger fluorescence. Therefore, by detecting the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state, the data stored in the rare earth ions can be read.

[0089] In some embodiments, the wavelength of the continuous laser is in the range of 400nm to 500nm, such as 405 or 488nm. In other embodiments, the wavelength of the continuous laser can be higher or lower, and the scope of the present disclosure is not limited in this respect.

[0090] In some embodiments, a photomultiplier tube or an avalanche photodiode may be used to detect the intensity of the fluorescence emitted by the rare earth ions in the second ion valence state in the glass substrate. In other embodiments, other types of detectors may be used to detect the intensity of the fluorescence emitted by the rare earth ions in the second ion valence state in the glass substrate, and the scope of the present disclosure is not limited in this respect.

[0091] The embodiment of the present disclosure also provides a data storage system, in which the data reading method described above can be executed. The data storage system includes an optical storage medium for storing data as described above. The optical storage medium can be used as Figure 1The optical disk 11 shown in the figure. The optical storage medium includes a glass substrate and rare earth ions doped in the glass substrate. The optical storage medium is an optical storage medium irradiated by ultraviolet light. Each rare earth ion is in a first ionic valence state or a second ionic valence state, the first ionic valence state is used to indicate the first data, and the second ionic valence state is used to indicate the second data. The data storage system also includes a pulse laser and a laser guide unit. The pulse laser is configured to generate a pulse laser. The pulse laser can be in the visible light or infrared band. The central wavelength of the pulse laser can include 800nm ​​or 1030nm. The pulse width of the pulse laser can include femtosecond or picosecond levels, for example, 220fs. The repetition frequency of the pulse laser can be in the range of kHz to hundreds of MHz. The single pulse energy of the pulse laser can be in the range of nanojoules to millijoules, for example, 0.5μJ. The laser guide unit is configured to focus the pulse laser into the glass substrate. The pulse laser is used to transform the ionic valence state of the irradiated rare earth ions in the glass substrate from the first ionic valence state to the second ionic valence state, thereby realizing the writing of data. The pulsed laser and the laser guide unit may be included in the Figure 1 In the read-write optical path module 12 shown in .

[0092] In some embodiments, the rare earth ions include europium (Eu) ions, and the first ion valence state of the europium ions is Eu. 3+ , and the second ion valence state of the europium ion is Eu 2+ In some other embodiments, the rare earth ions include samarium (Sm) ions, and the first ion valence state of the samarium ions is Sm 3+ , and the second ion valence state of the samarium ion is Sm 2+ When the rare earth ions are other ions, similar ion valence changes can also be achieved. Different ion valences of rare earth ions are used to indicate different data, so data writing to optical storage media can be achieved by changing the ion valence of rare earth ions.

[0093] In some embodiments, the data storage system further comprises an ultraviolet light source. The ultraviolet light source is configured to irradiate a glass substrate with ultraviolet light. The proportion of rare earth ions in the first ionic valence state in the glass substrate irradiated with ultraviolet light is higher than the proportion of rare earth ions in the second ionic valence state. The wavelength of the ultraviolet light can be in the range of 200nm to 400nm, for example, 375nm. After the glass substrate is irradiated with ultraviolet light, the signal-to-noise ratio of the optical storage medium is significantly improved. This is because the Eu generated during the glass firing process can be removed by irradiating the glass substrate with ultraviolet light. 2+ The ion is reoxidized to Eu 3+ ions, thereby reducing the Eu in the glass substrate 2+ ion content. The UV light source may be included in Figure 1 In the read-write optical path module 12 shown in .

[0094] In some embodiments, the data storage system further includes a continuous laser and a detector. The continuous laser is configured to irradiate the glass substrate with a continuous laser. The wavelength of the continuous laser may be in the range of 400nm to 500nm, for example including 405nm or 488nm. The detector is configured to detect the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state in the glass substrate, thereby enabling reading of data stored in the optical storage medium. The detector may include a photomultiplier tube or an avalanche photodiode or other types. When the glass substrate is irradiated with a continuous laser, the rare earth ions in the first ionic valence state and the rare earth ions in the second ionic valence state will exhibit different fluorescence states. For example, the rare earth ions in the first ionic valence state may basically not emit fluorescence or only emit a dimmer fluorescence, while the rare earth ions in the second ionic valence state will emit a stronger fluorescence. Therefore, by detecting the intensity of fluorescence emitted by the rare earth ions in the second ionic valence state, reading of data in the optical storage medium can be achieved. The continuous laser and the detector may be included in a device such as Figure 1 In the read-write optical path module 12 shown in .

[0095] In some embodiments, the data storage system further includes a position adjustment unit. The position adjustment unit is configured to control the laser guiding unit to focus the pulsed laser to different positions in the glass substrate to change the ion valence state of different rare earth ions in the glass substrate. By using the position adjustment unit to adjust the focus position of the pulsed laser, the writing of various data can be achieved. The position adjustment unit can be included in the embodiment of the present invention. Figure 1 In the read-write optical path module 12 shown in .

[0096] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A data storage method, It is characterized in that The method is used to store data in an optical storage medium, wherein the optical storage medium comprises a glass substrate doped with rare earth ions, and the method comprises: generating pulsed laser light by a pulsed laser; and Focusing the pulsed laser into the glass substrate, the pulsed laser is used to change the ion valence state of the irradiated rare earth ions in the glass substrate from a first ion valence state to a second ion valence state, thereby realizing data writing, wherein the optical storage medium is an optical storage medium irradiated by ultraviolet light, each rare earth ion is in the first ion valence state or the second ion valence state, the first ion valence state is used to indicate first data, and the second ion valence state is used to indicate second data; The optical storage medium irradiated by ultraviolet light is realized by irradiating the glass substrate with ultraviolet light, wherein the proportion of rare earth ions in the first ionic valence state in the glass substrate after irradiation by the ultraviolet light is higher than the proportion of rare earth ions in the second ionic valence state.

2. The data storage method according to claim 1, wherein the rare earth ions include europium (Eu) ions, and the first ion valence state of the europium ions is Eu. 3+ , and the second ion valence state of the europium ion is Eu 2+ .

3. The data storage method according to claim 1, wherein the rare earth ions include samarium (Sm) ions, and the first ion valence state of the samarium ions is Sm 3+ , and the second ion valence state of the samarium ion is Sm 2+ . 4 . The data storage method according to claim 1 , wherein the wavelength of the ultraviolet light is in the range of 200 nm to 400 nm. The data storage method according to claim 4 , wherein the wavelength of the ultraviolet light is 375 nm.

6. The data storage method according to claim 1, further comprising: include: irradiating the glass substrate with a continuous laser; as well as The light intensity of the fluorescence emitted by the rare earth ions in the second ion valence state in the glass substrate is detected, thereby realizing the reading of the data stored in the optical storage medium. 7 . The data storage method according to claim 6 , wherein the wavelength of the continuous laser light is in the range of 400 nm to 500 nm.

8. The data storage method according to claim 7, wherein the wavelength of the continuous laser light comprises 405 nm or 488 nm.

9. The data storage method according to claim 6, wherein the light intensity of the fluorescence is detected by using a photomultiplier tube or an avalanche photodiode.

10. The data storage method according to claim 1, wherein the pulse laser is in the visible light or infrared band. 11 . The data storage method according to claim 10 , wherein the central wavelength of the pulse laser comprises 800 nm or 1030 nm. 12 . The data storage method according to claim 1 , wherein the pulse width of the pulse laser comprises femtosecond or picosecond order.

13. The data storage method according to claim 12, wherein the pulse width of the pulse laser is 220 fs.

14. The data storage method according to claim 1, wherein a repetition frequency of the pulsed laser is in the range of kHz to hundreds of MHz.

15. The data storage method according to claim 1, wherein the single pulse energy of the pulse laser is in the range of nanojoule to millijoule. 16 . The data storage method according to claim 15 , wherein the single pulse energy of the pulse laser is 0.5 μJ.

17. The data storage method according to claim 1, further comprising: include: The pulse laser is controlled to be focused on different positions in the glass substrate to change the ion valence states of different rare earth ions in the glass substrate.

18. A data storage system, It is characterized in that The data storage system comprises: An optical storage medium for storing data, the optical storage medium comprising a glass substrate doped with rare earth ions, the optical storage medium being an optical storage medium irradiated by ultraviolet light, each rare earth ion being in a first ionic valence state or a second ionic valence state, the first ionic valence state being used to indicate first data, and the second ionic valence state being used to indicate second data; an ultraviolet light source, used to generate ultraviolet light and irradiate the glass substrate with the ultraviolet light, wherein the proportion of the rare earth ions in the first ionic valence state in the glass substrate after being irradiated by the ultraviolet light is higher than the proportion of the rare earth ions in the second ionic valence state; A pulse laser for generating pulsed laser light; and The laser guiding unit is used to focus the pulse laser into the glass substrate, and the pulse laser is used to change the ion valence state of the irradiated rare earth ions in the glass substrate from the first ion valence state to the second ion valence state, thereby realizing data writing.

19. The data storage system according to claim 18, wherein the rare earth ions include europium (Eu) ions, and the first ion valence state of the europium ions is Eu. 3+ , and the second ion valence state of the europium ion is Eu 2+ .

20. The data storage system of claim 18, wherein the rare earth ions include samarium (Sm) ions, the first ion valence state of the samarium ions being Sm 3+ , and the second ion valence state of the samarium ion is Sm 2+ .

21. The data storage system of claim 18, wherein the wavelength of the ultraviolet light is in the range of 200 nm to 400 nm.

22. The data storage system of claim 21, wherein the wavelength of the ultraviolet light is 375 nm.

23. The data storage system according to claim 18, further comprising: include: A continuous laser, used for irradiating the glass substrate with continuous laser light; as well as The detector is used to detect the intensity of the fluorescence emitted by the rare earth ions in the second ion valence state in the glass substrate, so as to read the data stored in the optical storage medium.

24. The data storage system of claim 23, wherein the wavelength of the continuous laser light is in the range of 400 nm to 500 nm.

25. The data storage system according to claim 24, wherein the wavelength of the continuous laser light comprises 405 nm or 488 nm.

26. The data storage system of claim 23, wherein the detector comprises a photomultiplier tube or an avalanche photodiode.

27. The data storage system of claim 18, wherein the pulsed laser is in the visible light or infrared band.

28. The data storage system according to claim 27, wherein a central wavelength of the pulse laser comprises 800 nm or 1030 nm.

29. The data storage system according to claim 18, wherein a pulse width of the pulse laser comprises a femtosecond or picosecond order.

30. The data storage system according to claim 29, wherein the pulse width of the pulse laser is 220 fs.

31. The data storage system of claim 18, wherein a repetition frequency of the pulsed laser is in the range of kHz to hundreds of MHz.

32. The data storage system of claim 18, wherein a single pulse energy of the pulse laser is in the range of nanojoules to millijoules.

33. The data storage system according to claim 32, wherein the single pulse energy of the pulse laser is 0.5 μJ.

34. The data storage system according to claim 18, further comprising: include: The position adjustment unit is used to control the laser guiding unit to focus the pulse laser to different positions in the glass substrate to change the ion valence states of different rare earth ions in the glass substrate.

Images