Laser arrangement and method for data storage, and data storage device

Abstract

The present invention relates to a laser arrangement (10) for data storage in a medium (12) that is transparent to the human eye, having the features of claim 1, a method for data storage in a medium (12) that is transparent to the human eye, having the features of the first additional independent claim, and a data storage device (24) for storing data, having the features of the second additional independent claim.

Description

[0001] Laser arrangement and method for data storage as well as a data storage device

[0002]

[0001] The present invention relates to a laser arrangement for data storage in a medium transparent to the human eye with features of claim 1, a method for data storage in a medium transparent to the human eye with features of the first dependent claim and a data storage device for storing data with features of the second dependent claim.

[0003]

[0002] The permanent storage of digital data has been researched for many decades using a number of physical principles and has been technically implemented on a large scale using a variety of different methods and media.

[0004]

[0003] Large amounts of data can be stored as magnetic states, for example, on a hard disk drive or a magnetic tape. It is also conceivable to store data in the form of load states, for example, on an SSD (solid-state drive) or FLASH drive. The encoding of data using optical reflectivities or phases, as on a CD (compact disk), DVD (digital versatile disc), or Blu-ray disc, is also known from the prior art.

[0005]

[0004] A disadvantage of all these implementations is that they require complex and expensive designs and are limited in durability because, for example, magnetic fields change over time or materials are subject to a chemical aging process. For example, HDDs are usually replaced after 5 to 10 years to reduce the risk of data loss. In addition, the write speed is relatively low.

[0006]

[0005] The present invention is based on the objective of providing a laser arrangement and a method for data storage as well as a data storage device, wherein data can be written or stored quickly, securely and durably with a cost-effective design.

[0007]

[0006] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0008]

[0007] According to the invention, a laser arrangement for data storage in a medium transparent to the human eye is proposed. This medium can be transparent to electromagnetic radiation in the wavelength range of 200 nm to 1100 nm, particularly in the range of 300 nm to 760 nm, and / or even beyond. The laser arrangement comprises a laser source. The laser source is configured to generate a pulsed laser beam. The laser arrangement comprises the medium transparent to the human eye. The laser source comprises a focusing device. The focusing device is configured to focus the laser beam onto and / or into the medium. The laser source is configured to generate the pulsed laser beam with a repetition rate of at least 50 MHz (megahertz), particularly in the range of 100 MHz to 100 GHz (gigahertz).The focusing device has a numerical aperture of at least 0.4, in particular at least 0.6.

[0009]

[0008] This allows data storage rates on the medium to be achieved using simple means, enabling write times acceptable for data storage applications. Data in this sense are volumetric modifications in the medium that arise from the interaction between the focused laser beam and the medium (so-called "voids"). These can be digital data represented by individual bits ("zero" / "one"). A void can, for example, represent a bit. A volumetric modification can, in particular, be a change in the refractive index of the medium. It is conceivable that a bit or a volumetric modification (a void) is generated by means of a single laser pulse or by means of several laser pulses of the pulsed laser beam.

[0010]

[0009] The medium can be in the form of a (circular) disk with a thickness ranging from 0.5 mm (millimeters) to 15 mm. The disk can comprise or be formed from quartz, soda-lime glass, heavy flint glass, borosilicate glass, plastic and / or polymer. The medium can be a data storage device described in detail below.

[0011]

[0010] It is conceivable that each individual laser pulse of the pulsed laser beam can be individually triggered. The laser source can include a nonlinear optical unit for frequency conversion. Conversions in the green (500 nm - 550 nm (nanometers)) or (deep) ultraviolet (200 nm - 365 nm) spectral range are particularly advantageous. The laser source can include a Mamyshev regenerator to, for example, further shorten laser pulses that are smaller than 100 ps.

[0012]

[0011] The laser source and / or the (focused) laser beam can be designed to be movable, in particular transversely to an axis of rotation of the medium. The laser system can include a scanner for moving the laser beam.

[0012] The focusing device can include at least one optical element. The optical element can be configured to control and / or adjust the polarization of the laser beam. The optical element can be configured to generate and / or control (detect) a linear, circular, and / or elliptical polarization of the laser beam.

[0013]

[0013] The focusing device can be configured such that the focus position of the focusing device can be adjusted at different depths in the medium. In other words, the depth or location of the focused laser beam in the medium can be set or varied as desired. The focusing device can be configured to actively compensate for (e.g., spherical) aberrations of the laser arrangement.

[0014]

[0014] In an advantageous embodiment of the solution according to the invention, the laser source can comprise a gain-switched semiconductor laser. The laser source can comprise a DFB laser (distributed feedback laser). The laser source can comprise a surface emitter or a VCSEL (vertical cavity surface emitting laser).

[0015]

[0015] This allows the laser source to be implemented using simple means.

[0016]

[0016] In an advantageous embodiment of the solution according to the invention, the laser source can comprise a laser amplifier or a laser amplifier chain. The laser amplifier or laser amplifier chain can comprise a fiber, rod, slab and / or disk amplifier.

[0017]

[0017] This allows a desired intensity of the laser beam, or one required for data storage, to be achieved using simple means.

[0018]

[0018] In an advantageous embodiment of the solution according to the invention, the laser source can be configured to generate the pulsed laser beam with a pulse energy in the range of 10 pJ (picojoules) to 1 pJ (microjoules). The laser source can be configured to generate the pulsed laser beam with a variable pulse energy.

[0019]

[0019] This allows the desired energy input of the laser beam, or the energy required for data storage, to be implemented using simple means. In particular, the variable pulse energies allow for the creation of volumetric modifications (voids) of different sizes. This makes it possible to encode more than a single information bit.

[0020] In an advantageous further development of the solution according to the invention, the laser source can be configured to generate the pulsed laser beam with a pulse duration of at most 100 ns (nanoseconds), in particular at most 100 ps (picoseconds), preferably at most 1 ps.

[0020]

[0021] This allows for the most optimal possible energy input of the laser beam into the medium.

[0021]

[0022] In an advantageous embodiment of the solution according to the invention, the laser arrangement can include a rotary device. The rotary device can be configured to rotate the medium. The rotary device can be configured to rotate the medium at a rotational frequency of at least 10 Hz, at least 100 Hz, or at least 400 Hz. Correspondingly, the medium can be configured to withstand this (high) rotational frequency. In other words, the medium can be configured for rotational frequencies of at least 10 Hz, at least 100 Hz, or at least 400 Hz. The rotary device and / or the medium can be designed to be movable, particularly transversely to the axis of rotation of the medium.

[0022]

[0023] This allows for a high data write rate to be achieved with simple means. Furthermore, cooling of the medium by the surrounding gaseous (or liquid) atmosphere flowing along it (due to the rotation and thus movement of the medium) can be implemented.

[0023]

[0024] The atmosphere surrounding the medium can be air or another gaseous medium (e.g., helium). This can serve both to improve cooling of the medium and to increase the speed of sound in the surrounding atmosphere to avoid supersonic effects. The surrounding atmosphere can be directed onto the medium. The laser setup can include the necessary components for this, such as at least one nozzle.

[0024]

[0025] In an advantageous embodiment of the solution according to the invention, the laser source can be configured to generate a temporal and / or spectral background. The background can be generated by means of continuous wave (CW) radiation and / or by means of (longer) laser pulses. The laser pulses can, for example, be positioned before and / or after the source.

[0025]

[0026] Particularly advantageous are lower harmonics of the center-of-mass wavelength, i.e. in the case of e.g. 343 nm (3rd harmonic), 515 nm (2nd harmonic) and / or 1030 nm (1st harmonic), which typically arise in the course of a non-linear optical arrangement.

[0026]

[0027] This allows for the most optimal energy input of the laser beam into the medium. In particular, the threshold energy can be reduced.

[0027]

[0028] The laser source may include an arrangement to compensate for changes in the inversion of the laser amplifier / laser amplifier chain, e.g., an adjustable cw background or variable pulses of the same or a different wavelength than the central wavelength of the laser source.

[0028]

[0029] The laser assembly may include a control unit. The control unit may be configured to control the laser source, the focusing device, and / or the rotation device.

[0029]

[0030] The control device can be configured to drive the laser source such that the pulsed laser beam is generated with a repetition rate of at least 50 MHz, particularly in the range of 100 MHz to 100 GHz. The control device can be configured to drive the laser source such that the pulsed laser beam is generated with a pulse energy, particularly variable, in the range of 10 pJ to 1 pJ. The control device can be configured to drive the laser source such that the pulsed laser beam is generated with a pulse duration, particularly variable, of a maximum of 100 ns, particularly a maximum of 100 ps, ​​preferably a maximum of 1 ps. The control device can be configured to drive the laser source such that a temporal and / or spectral background is generated, particularly by means of CW radiation and / or laser pulses.The control device can be configured to move the laser source and / or the (focused) laser beam, in particular transversely to the axis of rotation of the medium.

[0030]

[0031] The control unit can be configured to control the focusing device in such a way that the focusing depth in the medium can be set or varied.

[0031]

[0032] The control device can be configured to actuate the rotary device such that the rotary device rotates the medium at a rotational frequency of at least 10 Hz, at least 100 Hz, or at least 400 Hz. The control device can also be configured to move the rotary device and / or the medium, in particular transversely to the axis of rotation of the medium.

[0033] According to the invention, a method for storing data in a medium transparent to the human eye is proposed. The method comprises the following steps:

[0032] Generating a pulsed laser beam with a repetition rate of at least 50 MHz. The repetition rate of the generated laser beam can be in a range of 100 MHz to 100 GHz.

[0033] Providing the medium.

[0034] Focusing the laser beam into and / or onto the medium using a focusing device with a numerical aperture of at least 0.4. The numerical aperture of the focusing device can be at least 0.6.

[0035]

[0034] This allows data storage rates to be achieved on the medium that enable acceptable write times for data storage applications.

[0036]

[0035] In an advantageous further development of the solution according to the invention, the method can comprise the step:

[0037] Rotation of the medium. The rotation can be carried out at a rotational frequency of at least 10 Hz, 100 Hz, or at least 400 Hz.

[0038]

[0036] This allows the data to be written to the medium in the most optimal way possible and with simple means.

[0039]

[0037] In an advantageous further development of the solution according to the invention, the method can comprise the step:

[0040] Adjusting and / or varying the focusing depth of the laser beam in and / or on the medium. This can be achieved using a focusing device.

[0041]

[0038] This allows data to be written or stored within the medium at different depths using simple means.

[0042]

[0039] In an advantageous embodiment of the solution according to the invention, a laser arrangement as described above can be used to carry out the method.

[0040] Regarding the advantages achievable with the method, reference is made to the relevant descriptions of the laser arrangement. The measures described in connection with the laser arrangement and / or those explained below can be used to further develop the method.

[0043]

[0041] According to the invention, a data storage device for storing data is proposed. The data storage device comprises a rotationally symmetric disk. The disk is designed such that data in the form of volumetric modifications can be written onto and / or into the disk. The disk is made of a medium that is transparent to the human eye. The data storage device can be a data carrier.

[0044]

[0042] This allows data to be written quickly and permanently to and / or into the disk using simple means.

[0045]

[0043] The disc can have a circular, rectangular or square shape.

[0046]

[0044] In an advantageous further development of the solution according to the invention, the disc can have a thickness in a range of 0.5 mm to 15 mm.

[0047]

[0045] This allows several layers of volumetric modifications to be produced in the disk in the most optimal way possible.

[0048]

[0046] In an advantageous embodiment of the solution according to the invention, the disc can comprise or be formed from quartz, soda-lime glass, heavy flint glass, borosilicate glass, plastic and / or polymer. The disc can be produced using a float glass process.

[0049]

[0047] This makes it possible to implement a long-lasting, in particular chemically inert, data storage device using simple means.

[0050]

[0048] The disk can have a (low) threshold energy density for conversion or melting (volumetric modification) of a maximum of 3000 J / cm². 3 (Joules per cubic centimeter), in particular a maximum of 2000 J / cm³ 3 exhibit.

[0051]

[0049] In an advantageous embodiment of the solution according to the invention, the data storage device can be configured to be written with data by means of a laser arrangement according to the above descriptions and / or by means of a method according to the above descriptions.

[0050] With regard to the advantages achievable with the data storage device, reference is made to the relevant descriptions of the laser arrangement or the method. The measures described in connection with the laser arrangement or the method and / or those explained below can be used to further develop the data storage device.

[0052]

[0051] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the accompanying description of the figures with reference to the drawings.

[0053]

[0052] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0054]

[0053] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0055]

[0054] It shows,

[0056] Fig. 1 shows a schematic representation of a laser arrangement for data storage.

[0057]

[0055] The laser arrangement is designated as reference numeral 10 in Fig. 1. The laser arrangement 10 is configured for data storage in a medium 12 that is transparent to the human eye. The laser arrangement 10 comprises a laser source 14, the medium 12, and a focusing device 18. The laser source 14 is configured to generate a pulsed laser beam 16. The focusing device 18 is configured to focus the laser beam 16 onto and / or into the medium 12. The laser source 14 is configured to generate the pulsed laser beam 16 with a repetition rate of at least 50 MHz, particularly in a range of 100 MHz to 100 GHz. The focusing device 18 has a numerical aperture of at least 0.4.

[0058]

[0056] The laser source 14 can comprise a gain-switched semiconductor laser, in particular a DFB laser or a VCSEL.

[0057] The laser source 14 can comprise a laser amplifier 20 or a laser amplifier chain. The laser amplifier 20 or the laser amplifier chain can comprise a fiber, rod, slab and / or disk amplifier.

[0059]

[0058] The laser source 14 can be configured to generate the pulsed laser beam 16 with a pulse energy, in particular variable, in a range from 10 pJ to 1 pJ.

[0060]

[0059] The laser source 14 can be configured to generate the pulsed laser beam 16 with a pulse duration of at most 100 ns, in particular at most 100 ps, ​​preferably at most 1 ps.

[0061]

[0060] The laser arrangement 10 can include a rotary device 22. The rotary device 22 can be configured to rotate the medium 12. The rotary device 22 can be configured to rotate the medium 12 at a rotational frequency of at least 10 Hz. Correspondingly, the medium 12 can be configured to withstand this (high) rotational frequency. In other words, the medium 12 can be configured for a rotational frequency of at least 10 Hz. The rotary device 22 can be configured to hold the medium 12. The rotary device 22 can be configured to rotate the medium 12 about a rotational axis 30. This is indicated in Fig. 1 by an arrow bent about the rotational axis 30. The focused laser beam 16 and / or the medium 12 can be configured to be movable relative to each other. For this purpose, the laser source 14, the laser beam 16 and / or the rotary device 22 can be designed to be movable, in particular transverse to the axis of rotation 30.Thus, volumetric modifications can be generated within the entire diameter of the medium 12.

[0062]

[0061] The medium 12 can be rotated about the axis of rotation 30 by means of the rotary device 22. The laser beam 16, focused onto and / or into the medium 12 by means of the focusing device 18, can generate volumetric modifications in the medium 12 that represent the data to be stored in the form of bits. By adjusting the focus depth using the focusing device 18, different positions in the medium 12 can be described. In this way, a three-dimensional data density can be implemented in the medium 12. The entire volume (not just the surface) of the medium 12 can thus be used for data storage. Furthermore, the volumetric modifications, or the data, within the medium 12 are protected, in particular, from external influences.

[0063]

[0062] The medium 12 can be configured as a disk 26 of a data storage device 24, which will be described in detail below.

[0063] The laser source 14 can be configured to generate a temporal and / or spectral background, in particular by means of CW radiation and / or laser pulses.

[0064]

[0064] The laser arrangement 10 can include a control device 28. The control device 28 can be configured to control the laser source 14, the focusing device 18 and / or the rotary device 22.

[0065]

[0065] The control device 28 can be configured to control the laser source 14 such that the pulsed laser beam 16 is generated with a repetition rate of at least 50 MHz, particularly in a range of 100 MHz to 100 GHz. The control device 28 can be configured to control the laser source 14 such that the pulsed laser beam 16 is generated with a pulse energy (particularly variable) in a range of 10 pJ to 1 pJ. The control device 28 can be configured to control the laser source 14 such that the pulsed laser beam 16 is generated with a pulse duration of at most 100 ns, particularly at most 100 ps, ​​preferably at most 1 ps. The control device 28 can be configured to control the laser source 14 in such a way that a temporal and / or spectral background is generated, in particular by means of cw radiation and / or laser pulses.

[0066]

[0066] The control device 28 can be configured to control the focusing device 18 in such a way that the focusing depth in the medium 12 can be set or varied.

[0067]

[0067] The control device 28 can be configured to control the rotary device 22 such that the rotary device 22 rotates the medium 12 at a rotational frequency of at least 10 Hz. The control device 28 can be configured to move the laser source 14, the laser beam 16 and / or the rotary device 22, in particular transversely to the axis of rotation 30.

[0068]

[0068] The following describes a method for storing data in a medium 12 that is transparent to the human eye, with reference to Fig. 1. The method comprises the following steps:

[0069] Generating a pulsed laser beam 16 with a repetition rate of at least 50 MHz, particularly in a range of 100 MHz to 100 GHz.

[0070] Providing the medium 12. Focusing the laser beam 16 into and / or onto the medium 12 by means of a focusing device 18 with a numerical aperture of at least 0.4.

[0071]

[0069] The method may include at least one or more of the following steps:

[0072] Rotation of the medium 12, in particular with a rotation frequency of at least 10 Hz.

[0073] Adjusting and / or varying the focusing depth of the laser beam 16 in and / or on the medium 12.

[0074]

[0070] To carry out the method, a laser arrangement 10 according to the above descriptions can be used. The laser arrangement 10 can be the laser arrangement 10 shown in Fig. 1.

[0075]

[0071] A data storage device 24 for storing data is described below with reference to Fig. 1. The data storage device 24 comprises a rotationally symmetric disk 26. The disk 26 is configured such that data in the form of volumetric modifications can be written into and / or onto the disk 26. The disk 26 is made of a medium 12 that is transparent to the human eye.

[0076]

[0072] The disk 26 can have a thickness in the range of 0.5 mm to 15 mm. The disk 26 can have a circular shape.

[0077]

[0073] The disc 26 can comprise or be formed from quartz, soda-lime glass, heavy flint glass, borosilicate glass, plastic and / or polymer. The disc 26 can be manufactured using the float glass process.

[0078]

[0074] The data storage device 24 can be configured to be written with data (in the form of volumetric modifications) by means of a laser arrangement 10 according to the above descriptions and / or by means of a method according to the above descriptions. The laser arrangement 10 can be the laser arrangement 10 shown in Fig. 1. The method can be the method shown in Fig. 1. List of reference numerals

[0079] 10 Laser arrangement

[0080] 12 Medium transparent to the human eye 14 Laser source

[0081] 16 Laser beam

[0082] 18 Focusing device

[0083] 20 laser amplifiers

[0084] 22 Rotary device

[0085] 24 data storage devices

[0086] 26 discs

[0087] 28 Control unit

[0088] 30 Rotary axis

Claims

Patent claims 1. Laser arrangement (10) for data storage in a medium (12) transparent to the human eye, comprising a laser source (14) for generating a pulsed laser beam (16), the medium (12), a focusing device (18) for focusing the laser beam (16) onto and / or into the medium (12), characterized by that the laser source (14) is configured to generate the pulsed laser beam (16) with a repetition rate of at least 50 MHz, in particular in a range of 100 MHz to 100 GHz, wherein the focusing device (18) has a numerical aperture of at least 0.

4.

2. Laser arrangement (10) according to claim 1, characterized in that the laser source (14) comprises a gain-switched semiconductor laser, in particular a DFB laser or a VCSEL.

3. Laser arrangement (10) according to claim 1 or 2, characterized in that the laser source (14) comprises a laser amplifier (20) or a laser amplifier chain, in particular a fiber, rod, slab and / or disk amplifier.

4. Laser arrangement (10) according to one of the preceding claims, characterized in that the laser source (14) is configured to generate the pulsed laser beam (16) with a pulse energy, in particular variable, in a range from 10 pJ to 1 pJ.

5. Laser arrangement (10) according to one of the preceding claims, characterized in that the laser source (14) is configured to generate the pulsed laser beam (16) with a pulse duration of at most 100 ns, in particular at most 100 ps, ​​preferably at most 1 ps.

6. Laser arrangement (10) according to one of the preceding claims, characterized in that the laser arrangement (10) comprises a rotary device (22) for rotating the medium (12), wherein the rotary device (22) is configured to rotate the medium (12) at a rotational frequency of at least 10 Hz or at least 100 Hz or at least 400 Hz.

7. Laser arrangement (10) according to one of the preceding claims, characterized in that the laser source (14) is configured to generate a temporal and / or spectral background, in particular by means of cw radiation and / or laser pulses.

8. Method for storing data in a medium transparent to the human eye (12) comprising the steps: Generating a pulsed laser beam (16) with a repetition rate of at least 50 MHz, particularly in a range of 100 MHz to 100 GHz; Providing the medium (12); Focusing the laser beam (16) into and / or onto the medium (12) by means of a focusing device (18) with a numerical aperture of at least 0.

4.

9. The method according to claim 8, characterized by the step: Rotation of the medium (12), in particular with a rotation frequency of at least 10 Hz.

10. Method according to claim 8 or 9, characterized by the step: Adjusting and / or varying the focusing depth of the laser beam (16) in and / or on the medium (12).

11. Method according to one of claims 8 to 10, characterized in that a laser arrangement (10) according to one of claims 1 to 7 is used to carry out the method.

12. Data storage device (24) for storing data comprising a rotationally symmetric disk (26) characterized by that the disk (26) is arranged such that data in the form of volumetric modifications can be written into and / or onto the disk (26), wherein the disk (26) is formed from a medium (12) that is transparent to the human eye.

13. Data storage device (24) according to claim 12, characterized in that the disk (26) has a thickness in a range of 0.5 mm to 15 mm.

14. Data storage device (24) according to claim 12 or 13, characterized in that the disk (26) comprises or is formed from quartz, soda-lime glass, heavy flint glass, borosilicate glass, plastic and / or polymer.

15. Data storage device (24) according to one of claims 12 to 14, characterized in that the data storage device (24) is configured to be written with data by means of a laser arrangement (10) according to one of claims 1 to 7 and / or a method according to one of claims 8 to 11.

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