KR101211845B1 - holographic storage device using solid immersion lens, storage method and recording method using the same - Google Patents

Abstract

The present invention relates to a holographic data recording apparatus using a solid immersion lens. A holographic data recording apparatus using a solid immersion lens according to an embodiment of the present invention includes optical means including a light source means for irradiating a beam, an objective lens system for focusing the beam on a recording layer of a disc, a light source means and an optical means. A holographic recording apparatus having optical path forming means for forming an optical path therebetween, comprising: an optical path forming means, for separating an optical means and one beam incident on the disk side into a signal beam and a reference beam on the same optical path Spatial Light Modulator (SLM); And a solid immersion lens provided in the optical means, which reduces the size (d = λ / NA) of the beam spot focused on the recording layer of the disc by increasing the numerical aperture (NA = nsinθ) of the objective lens system. (SIL, Solid Immersion Lens);

Description

Holographic storage device using solid immersion lens, storage method and recording method using the same}

The present invention relates to a holographic data recording apparatus, a recording method and a reproduction method using the same.

As an optical information processing device that processes optical information, compact discs (CDs), digital versatile discs (DVDs), HD-DVDs, and Blu-ray Discs (BDs) are used. As the demand for a system increases, optical information processing apparatuses using near field recording (NFR) and holography have attracted attention.

Optical information processing apparatus using holography is a page-oriented memory in principle of recording and reproducing image information. This can speed up the data rate.

An optical information processing apparatus using holography superimposes an information beam and a reference beam including image information of original data onto an optical information recording medium and irradiates an interference pattern resulting from the interference pattern. Is recorded on the optical information recording medium.

In order to reproduce the recorded optical information, when the reference light is irradiated onto the optical information recording medium, the reference light is diffracted by the interference pattern to generate regenerated light. If the recording reference light and the reproduction reference light are the same, reproduction light containing the same optical information as the optical information included in the signal light during recording is generated.

On the other hand, the image of the data page reproduced by the reproduction light is detected by a light receiving element such as a complementary metal-oxide semiconductor (CMOS) or a charge coupled device (CCD), the detected data page is subjected to a series of signal processing and decoding process The original data is restored.

The optical information processing apparatus using holography can dramatically improve the storage density through a multiplexing technique in which image information is superimposed on the same place of a recording medium, but an optical system having a numerical aperture of 1 or less of a lens used for recording and reproduction can be used. By use, the size of the recorded spot was recorded in micro units.

In the optical information processing apparatus using holography, superposition recording is applied in the case of collinear holography, but the area density is low due to the low numerical aperture of the objective lens for recording, and in the case of micro holography Although recording in multiple layers (75 layers) is difficult, complicated servo technology is required to precisely move the pointing position.

The present invention devised to solve the problems described above, by reducing the size of the recorded spot by nano units to overlap recording, further improves the storage density of the recording medium, the storage of more than normal holography even by single layer recording An object of the present invention is to provide a holographic data recording apparatus capable of realizing a capacity, a recording method and a reproducing method using the same.

The present invention for achieving the object as described above, the optical means 30 is provided with a light source means 10 for irradiating a beam, an objective lens system for focusing the beam on the recording layer of the disk 90, and the light source means 10. A holographic recording apparatus comprising an optical path forming means 20 for forming an optical path between an optical path 30 and an optical means 30, the optical path forming means 20 being provided in the optical path forming means 20, A spatial light modulator (SLM) 22 for separating one beam incident on the disk 90 side into a signal beam and a reference beam on the same optical path; And a size (d = λ) of the beam spot provided in the optical means 30 and focused on the recording layer of the disc 90 by increasing the numerical aperture (NA = nsinθ) of the objective lens system. A holographic data recording apparatus using a solid immersion lens configured to include a solid immersion lens (SIL) 32 for reducing the size of NA / NA).

The light source means 10 may include a green light irradiator 11 for irradiating a green laser having a wavelength λ = 532 nm when data is recorded.

In addition, the spatial light modulator 22 may display a closed-loop light canceling unit 22a that divides and divides the cross section of the beam into a central part and a circumferential part on a path through which the beam passes.

In addition, the spatial light modulator 22 may be switched to a plurality of modes for selectively generating or extinguishing a region inside the light canceling unit 22a having a closed ring shape or extinguishing the light canceling unit 22a itself. have.

In addition, a central portion of the beam positioned inside the photo-mute part 22a may be a signal beam, and a circumferential portion of the beam positioned outside the photo-mute part 22a may be a reference beam.

In addition, the optical path forming means 20 gives a phase difference of about 1/4 wavelength to a signal beam and a reference beam in a linear polarization state separated by the spatial light modulator 22, thereby providing circular polarization. It can be configured to include; (QWP, guarter wave plate, quarter wave length plate (24)) to be converted to the incident to the optical means 30 side.

In addition, after focusing on the disk 90, the S polarized light is separated from the beam reflected and returned in parallel with the path of incidence, thereby receiving light such as a complementary metal-oxide semiconductor (CMOS) and a charge coupled device (CCD). And a first beam splitter (BS) 23 reflecting to the device side.

The solid immersion lens 32 may be provided between the objective lens 31 of the objective lens system and the disk 90 at intervals of 0 nm or more and 20 nm or less with the recording layer of the disc 90.

The solid immersion lens 32 may have a refractive index such that the numerical aperture of the optical system including the objective lens system is greater than one.

In addition, the light source means 10 may include a red light irradiator 12 for irradiating a beam with a red laser having a wavelength λ = 633 nm.

The optical path forming unit 20 reflects the second laser beam splitter 21 to reflect the red laser emitted from the red light irradiator 12 to the same optical path as the optical path for data recording. It can be configured to include.

In addition, the present invention, by using the spatial light modulator (SLM, Spatial Light Modulator) (22), by separating the one beam irradiated from the light source means 10 into a signal beam and a reference beam on the same optical path, A beam separation step of advancing toward the light source means 10 and the disk 90; By using the solid immersion lens (SIL) 32, the numerical aperture (NA) of the objective lens system (NA = nsinθ) is increased to 1 or more, so that the recording layer of the disk 90 is increased. A beam reduction step of reducing the size (d = λ / NA) of the focused beam spot; And an overlapping recording step of recording data while focusing the signal beam and the reference beam whose size is reduced in the beam reduction step at the same point on the recording layer of the disc 90, and overlapping and recording a part of the spots. The recording method using a holographic data recording apparatus using a solid immersion lens is another technical point.

Here, the red light irradiation step of irradiating the red laser to the light path side for data recording by using the red light irradiator 12; By using the second beam splitter (BS) installed on the optical path for data recording, the light source means 10 and the disk 90 side on the same optical path as the optical path for data recording. A red light adjusting step of switching a traveling direction of the red laser; And a focus position confirming step of focusing the red laser incident to the light source means 10 and the disk 90 through the red light adjusting step to the recording position on the disk 90 and confirming and adjusting the recording position. It can be configured.

In addition, the present invention is a planar shape in which the shape of the light canceling portion 22a provided by the spatial light modulator (SLM) 22 is eliminated from the closed annular linear region to the closed annular inner region. A signal beam canceling step of converting the signal beam to cancel the signal beam; By using the solid immersion lens (SIL) according to claim 1, the reference beam remaining through the mode switching step is subjected to at least one numerical aperture (NA) (NA = nsinθ). A reference beam focusing step of focusing on the recording layer of the disc 90; Using the first beam splitter (BS) 23, the S-polarized light is separated from the reference beam focused on the recording position of the disk 90 and then returned in parallel to the same path as the incident path. Recording data extraction step; And a data reproducing step of inputting the S-polarized light extracted in the recording data extraction step into a light receiving element and outputting a reproducing signal from the reference beam reflected by the disc 90. The reproduction method using the data recording apparatus is another technical point.

According to the present invention having the above-described configuration, while reducing the size of the recording spot by using a solid immersion lens (SIL), a single laser beam is signaled by a spatial light modulator (SLM). And recording beams are superimposed and separated by a reference beam.

By increasing the numerical aperture to 1 or more using a solid immersion lens, the size of the recording spot can be reduced to nano size for superimposed recording, and the storage density of the recording medium can be applied by applying a multiplexing technique for superimposing recording spots. Can be further improved to record more information in a single recording layer.

In addition, by implementing recording, reproducing and disc position control on a single optical path, it is possible to build a compact optical system by simplifying an existing complex optical system, and to improve the storage capacity of a single recording layer. By minimizing the mechanical driving required for fine movement, it is possible to solve the difficulty of servo control that has been followed to precisely move the pointing position.

In addition, it is possible to realize better recording density than the conventional holography recording device and near field recording device (NFR), and it is compatible with the existing holography recording device and near field recording device to store next-generation optical information. As a device, it can be widely applied to high resolution movies and data backup fields.

1-a conceptual diagram showing a holographic data recording apparatus using a solid immersion lens according to an embodiment of the present invention
2 is a conceptual diagram illustrating an example of a process of recording and focusing on a disk by dividing and reducing a green laser into a signal beam and a reference beam using a spatial light modulator and a solid immersion lens;
3 is a conceptual diagram illustrating an example of a process of focusing using a red laser;
4-Photograph showing the state in which the signal beam and the reference beam are focused on the disc, and the luminance according to the size of the signal beam and the reference beam and the traveling state of the beam.
5 is a graph showing the position selectivity of the optical information reproduction light incident on the light receiving element by the holographic data recording apparatus according to the embodiment of the present invention;
FIG. 6 is a conceptual diagram illustrating an example of a process of erasing a signal beam, focusing only a reference beam on a disk, and playing the same using a spatial light modulator and a solid immersion lens; FIG.
7 to 4 are graphs showing a reproduction signal of the focused beam spot of FIG.

1 is a conceptual diagram illustrating a holographic data recording apparatus using a solid immersion lens according to an embodiment of the present invention.

According to the present invention, there is provided a light source means (10) for irradiating a beam, an optical means (30) provided with an objective lens system for focusing the beam on the recording layer of the disk (90), and the light source means (10) and the optical means (30). A holographic storage device having optical path forming means 20 for forming an optical path therebetween is known in the art.

According to the present invention, a spatial light modulator (SLM) 22 is provided in the optical path forming means 20, and a solid immersion lens (SIL) 32 is provided in the optical means 30. It has a configuration provided.

The spatial light modulator 22 separates one beam incident on the optical means 30 and the disk 90 into a signal beam and a reference beam on the same optical path, and the solid immersion lens 32. Increases the numerical aperture (NA = nsinθ) of the objective lens system, thereby reducing the size of the beam spot focused on the recording layer of the disc 90 (d = λ / NA).

In one embodiment of the present invention shown in Figure 1, the light source means 10 is provided with a green light irradiator 11, a red light irradiator 13, the optical path forming means 20 is the light source means 10 side The second light splitter 21, the spatial light modulator 22, the first light splitter 23, and the quarter-wave plate 24 are sequentially provided, and the optical means 30 comprises an objective lens. 31), the solid immersion lens 32 has a structure provided.

When recording data, the green light irradiator 11 irradiates a green laser having a wavelength λ = 532 nm, and the green laser passes through the spatial light modulator 22 and the solid immersion lens 32 and proceeds toward the disk 90. do.

In the optical information processing apparatus using holography, a signal beam and a reference beam including image information of original data are overlapped and irradiated with an optical information recording medium, and an interference pattern ( interference pattern) is recorded on the optical information recording medium.

2A and 2B, a green laser is separated into a signal beam and a reference beam using the spatial light modulator 22, and the solid immersion lens 32 is used. This is a conceptual diagram illustrating an example of a process of reducing the beam size to focus and record on the disc 90.

A spatial light modulator (SLM) is a device that spatially controls the amplitude, phase, polarization state, direction of travel, etc. of an optical wave by an input signal such as a battery or light, and the like (a) and (b) of FIG. 2. In the embodiment of the present invention shown in FIG. 2, the spatial light modulator 22 separates a plurality of beams on the same optical path by displaying the light canceller 22a on a single optical path through which one green laser passes. Form.

As shown in (a) of FIG. 2, the light canceling unit 22a is formed in a closed ring shape and divides a cross section of the beam into a central part and a circumferential part. The beam is located inside the light removing part 22a. The signal beam and the reference beam are advanced along the same optical path by using the central portion of the signal beam as the signal beam and the circumference of the beam located outside the light erasing portion 22a as the reference beam.

The spatial light modulator 22 is switched to a plurality of modes for selectively generating or extinguishing a region inside the optical canceller 22a having a closed ring shape, or extinguishing the optical canceller 22a itself.

At the time of data recording, as shown in FIG. 2 (b), the light canceling unit 22A is displayed in a closed loop shape so that one beam is separated into an inner signal beam and an outer reference beam to travel in the same optical path. Let's do it.

In the focusing process for data recording (described below), as shown in FIG. 3, the light canceling section 22a itself is extinguished so that the beam can proceed as it is, and during data reproduction (described below), FIG. As shown in the drawing, the light canceling unit 22a may be extended to the inside of the closed ring shape to remove the signal beam to advance only the reference beam.

The 1/4 of the signal beam and the reference beam in a linear polarization state (generally laser is linearly polarized) separated by the spatial light modulator 22 form a phase difference of 1/4 wavelength. Passing through a wave plate (QWP, guarter wave plate, quarter wave length plate) 24 is converted into circular polarization and then incident to the optical means 30 side.

When the trajectory of a wave oscillates linearly, it is called linear polarization. For some reason, two components of a wave have different phases but two components of the same size If the phase difference is 90 °, the peak of the wave turns clockwise or counterclockwise, which is called circular polarization.

As such, a medium for converting linearly polarized light into circularly polarized light and a device having a phase difference of about 1/4 wavelength is called a quarter wave plate (QWP). Since the magnitudes of the two axial components are different and the phase difference is arbitrary, the trajectory of the peak of the wave viewed from the opposite side of the traveling direction is an ellipse having an arbitrary shape, which is called elliptical polarization. do.

The solid immersion lens 32 is provided between the objective lens 31 and the disk 90 of the objective lens system with a recording layer of the disk 90 at an interval of 0 nm or more and 20 nm or less, and according to the present invention. In the example, the solid immersion lens 32 is provided at intervals of 20 nm.

The disk to be recorded by the existing micro-holographic recording apparatus has a structure in which a cover having a thickness of about 600 µm is formed outside the recording layer having a thickness of 300 to 400 µm, but the disk to which the embodiment of the present invention is applied is conventional. A cover having a thickness of 30 nm or less is formed so that the distance between the recording layer and the solid immersion lens 32 is not more than 30 nm, or the recording layer is exposed without the cover. It has a structure.

In general, the objective lens 31 of the objective lens system constituting the objective lens system has a numerical aperture of 0.66, the solid immersion lens 32 has a high refractive index of 2.266 and the optical system has a numerical aperture of 1.50. The area of the signal beam has a numerical aperture of 0.0 <NA <0.95, and the area of the auxiliary beam has a numerical aperture of 1.0 <NA <1.5.

The resolution can be expressed by the minimum distance d of two identifiable points. If the wavelength of the illumination light is λ and the numerical aperture of the objective lens is a, then d = λ / a. Since the minimum distance d of the two identifiable points is proportional to the size of the beam spot focused on the recording layer of the disc 90, the size of the beam spot focused on the recording layer of the disc 90 is equal to λ / NA. Proportional.

That is, when the numerical aperture NA exceeds 1 in a state where the numerical aperture NA is less than 1, the size of the beam spot is drastically reduced, so that the numerical aperture is increased to 1 or more using the solid immersion lens 32. It is possible to reduce the size of the recording spot, which had it, to nano size.

In the embodiment shown in Fig. 2, an area with a numerical aperture of 1 or less is used as a signal beam, and an area with at least 1 is used as a reference beam, 20 nm apart from the recording layer of the disc 90, and the numerical aperture of the objective lens is 0.66. In this case, by applying the solid immersion lens 32 having a refractive index N 2.266, an effective NA of 1.50 may be realized in the reference beam region having a large incident angle, as shown in FIG. 2.

4 is a photograph showing a state in which a signal beam and a reference beam are focused on the disk 90 through the solid immersion lens 32, and relative luminance according to the size of the signal beam and the reference beam and the traveling state of the beam. .

The left region corresponds to the solid immersion lens 32 and the right region corresponds to the disk 90 on the basis of a 20 nm air-gap (shown in the form of a dotted white line) continuously formed in the center in the longitudinal direction.

The signal beam and the reference beams on the outside (upper and lower side in FIG. 4) are incident to the solid immersion lens 32 on the left side and separated while being separated from each other, and are reduced while proceeding to the right side. It can be seen that the signal beam and the reference beam overlap and are focused on the left end of the disk 90 to form a hologram.

FIG. 3 is a process of focusing using a red laser and confirming and adjusting a recording position corresponding to a focusing position of a signal beam and a reference beam before recording data on the disc 90 by the above process. It is a conceptual diagram shown to illustrate an example.

The red light irradiator 12 irradiates a red laser having a wavelength lambda = 633 nm toward the light path side of the green laser for data recording, and the red laser irradiated by the red light irradiator 12 is provided on the optical path of the green laser. The second beam splitter 21 reflects and travels in the same optical path as the optical path for data recording.

Beam splitter (BS) is an optical device used to divide incident light bundles into two or more by using intensity or spectral lines. Half-mirror division for intensity and color-selective mirror division for spectral division are common. Is being used.

The red laser, which enters the same optical path as the optical path for data recording, passes through the spatial light modulator 22 without being deformed and the solid state immersion lens 32 as it is. ) And proceeds to the disk 90 side.

After focusing on the disk 90, the red laser, which is reflected and proceeds back in parallel in the same path as the incident path, has the S-polarized light separated by the first beam splitter (BS) 23 and is recorded. The signal is reflected to a side of an electro-optical detector such as a complementary metal-oxide semiconductor and a charge coupled device (CCD).

When focusing for data recording, a red laser having a wavelength different from that of a green laser used for data recording is used to prevent damage to the disk 90 and to detect a reflected signal according to a position. The area of the total numerical aperture is defined as the incidence surface of the solid immersion lens 32 without being influenced by the light canceling section 22a.

According to the holographic recording apparatus, a multiplexed superposition recording method of partially overlapping and recording a recording spot corresponding to one beam focusing point area may be applied. FIG. 5 is a holographic data recording apparatus according to an embodiment of the present invention. Is a graph showing the shifting selectivity of the optical information reproduction light incident on the light receiving element.

Shifting selectivity represents the intensity of light incident on the light receiving element, and the horizontal axis of the graph represents distance (ratio of wavelength lambda) and the vertical axis represents relative magnitude of position selectivity.

Based on the point where the intensity of light for one recording spot is strongest (1 on the vertical axis), the distance to the first null (e.g., 0.2 or less on the vertical axis) of light detection is disabled at 0.32λ. Since it is the corresponding point and green laser wavelength (lambda) = 532 nm, according to this invention, it can be confirmed that superimposition recording is possible at a narrow interval of 170 nm.

When the reference beam is irradiated with the optical information recording medium, the reference beam is diffracted by the interference pattern generated on the recording medium by the signal beam and the reference beam during recording, and thus the reproduction light is generated. When the reference beams are the same, reproduction light including the same optical information as the optical information included in the signal beam is generated during recording.

In the reproduction using the embodiment of the present invention, a green laser is used but a region having a numerical aperture of 1 or more, that is, a reference beam is used. FIG. 6 focuses only the reference beam on the disc 90, and reproduces recorded data. It is a conceptual diagram shown to illustrate an example.

While passing through the spatial light modulator 22 in a state where the light canceling portion 22a is extended to a closed annular inner side, only the outer reference beam is the solid immersion lens 32 while the inner signal beam is removed. ) And proceeds to the disk 90 side.

After focusing on the disc 90, the reference beam, which includes the image information of the data page and is reflected and proceeds back in parallel with the path of incidence, is the first beam splitter (BS). 23) separates the S-polarized light in which an electric field is formed perpendicular to the direction of light travel, and is directed to a light receiving element such as a complementary metal-oxide semiconductor (CCD) and a charge coupled device (CCD) for detecting signals and information relating to the recording position. Reflected.

An image of a data page is detected through a reference beam incident on the light receiving element, and the detected data page is restored to original data through a series of signal processing and decoding processes.

FIG. 7 is a graph illustrating a state in which the reproduced image signal of the recorded hologram of FIG. 4 is implemented through the light receiving element, and outputs an image of the signal beam incident on the light receiving element using the reflective reproducing method ( Middle circular part) is shown.

Hereinafter, a recording method and a reproducing method using a holographic data recording apparatus using a solid immersion lens according to the present invention having the above configuration will be described, and a holographic data recording apparatus using the solid immersion lens will be described. For the content overlapping with the description will be omitted.

One embodiment of the recording method using the holographic data recording apparatus using a solid immersion lens according to the present invention, after focusing the recording position through the red light irradiation step, red light adjustment step, focus positioning step, beam separation step, beam The data is overwritten on the fraudulent disc 90 by a reduction step and a superimposed recording step.

In the red light irradiation step, the red laser is irradiated to the light path side for data recording by using the red light irradiator 12.

In the red light adjusting step, by using the second beam splitter 21 provided on the optical path for data recording, the light source means 10 and the disk 90 side on the same optical path as the optical path for data recording. Reverse the direction of travel of the red laser.

In the focus position confirming step, the red laser incident to the light source means 10 and the disk 90 through the red light adjusting step is focused on the recording position on the disk 90, and the recording position is confirmed and adjusted.

In the beam separation step, the green laser is irradiated using the green light irradiator 11, and one green laser is separated into a signal beam and a reference beam on the same optical path by using the spatial light modulator 22. It proceeds to the light source means 10 and the disk 90 side.

In the beam reduction step, by using the solid immersion lens 32, the numerical aperture (NA = nsinθ) of the objective lens system is increased to 1 or more, so that the size of the beam spot focused on the recording layer of the disc 90 ( d = λ / NA).

In the superimposition recording step, the signal beam and the reference beam whose size is reduced in the beam reduction step are recorded at the same point on the recording layer of the disk 90, and data is recorded, but a portion of the spot is overlapped and recorded.

An embodiment of a reproduction method using a holographic data recording apparatus using a solid immersion lens according to the present invention is performed through a signal beam erasing step, a reference beam focusing step, a recording data extraction step, and a data reproducing step.

In the signal beam erasing step, the shape of the light canceling section 22a provided by the spatial light modulator 22 is changed from a closed loop linear to a surface where the closed annular inner region disappears. Erase.

In the reference beam focusing step, by using the solid immersion lens 32, the reference beam remaining through the mode switching step is focused on the recording layer of the disc 90 with one or more numerical apertures (NA = nsinθ). do.

In the recording data extraction step, the S-polarized light is focused on the reference beam which is focused on the recording position of the disk 90 by using the first beam splitter 23 and then returns in parallel with the same path as the incident path. Separate.

In the data reproducing step, the S-polarized light extracted in the recording data extraction step is incident on the light receiving element, and a reproduction signal is output from the reference beam reflected by the disc 90.

According to the holographic data recording apparatus using the solid immersion lens according to the present invention as described above, the recording method and the reproduction method using the same, while reducing the size of the recording spot by using the solid immersion lens 32, The spatial light modulator 22 separates one laser beam into a signal beam and a reference beam so that the recording spots are overlapped and recordable.

By increasing the numerical aperture to 1 or more by using the solid immersion lens 32, the size of the recording spot can be reduced to nano size for superimposed recording, and by applying a multiplexing technique for superimposing recording spots, By further improving the storage density of the recording medium, more information can be recorded in a single recording layer.

In addition, by implementing recording, reproducing and disc position control on a single optical path, it is possible to build a compact optical system by simplifying an existing complex optical system, and to improve the storage capacity of a single recording layer. By minimizing the mechanical driving required for fine movement, it is possible to solve the difficulty of servo control that has been followed to precisely move the pointing position.

On the other hand, spherical aberration is also called columnar aberration, and when the light rays exiting at one point are reflected at the spherical mirror or pass through the spherical lens, the shadow is blurred. This is a visible phenomenon, where light rays from one point on an axis do not converge at a point and the position of the intersection varies depending on the angle of inclination with respect to the axis.

As the thickness of the recording layer of the disk increases, that is, the point away from one surface of the recording layer adjacent to the solid immersion lens 32, the spherical aberration increases, thereby reducing optical performance. By this, excellent optical performance can be reliably implemented.

In addition, it is possible to realize better recording density than the conventional holography recording device and near field recording device (NFR), and it is compatible with the existing holography recording device and near field recording device to store next-generation optical information. As a device, it can be widely applied to high resolution movies and data backup fields.

The present invention has been described with reference to preferred embodiments of the present invention, but the present invention is not limited to these embodiments, and the claims and detailed description of the present invention together with the embodiments in which the above embodiments are simply combined with existing known technologies. In the present invention, it can be seen that the technology that can be modified and used by those skilled in the art are naturally included in the technical scope of the present invention.

10: light source means 11: green light irradiator
12: red light irradiator 20: optical path forming means
21 second beam splitter 22 spatial light modulator
22a: light rejection 23: first beam splitter
24: 1/4 wavelength plate 30: optical means
31: objective lens 32: solid immersion lens
90: disk

Claims (14)

Optical means 30 having a light source means 10 for irradiating a beam, an objective lens system for focusing the beam on the recording layer of the disc 90, and a sight between the light source means 10 and the optical means 30; In the holographic recording apparatus provided with the optical path forming means 20 for forming a furnace,
Spatial light modulator (SLM) is provided in the optical path forming means 20 and separates one beam incident to the optical means 30 and the disk 90 into a signal beam and a reference beam on the same optical path. (22); And
The size of the beam spot provided in the optical means 30 and focused on the recording layer of the disc 90 by increasing the numerical aperture (NA = nsinθ) of the objective lens system (d = λ / A solid immersion lens (SIL) 32 for reducing NA);
Including but not limited to:
The spatial light modulator 22,
A holographic data recording apparatus using a solid immersion lens, characterized in that for displaying a closed annular light canceling portion (22a) for separating and partitioning the cross section of the beam into a central portion and a circumferential portion on a path through which the beam passes.
The method of claim 1, wherein the light source means 10,
A green light irradiator 11 for irradiating a green laser having a wavelength λ = 532 nm when recording data;
Holographic data recording apparatus using a solid immersion lens, characterized in that comprising a.
delete The method of claim 1, wherein the spatial light modulator 22,
Holographic using a solid immersion lens, characterized in that it is switched to a plurality of modes to selectively generate or disappear the area inside the light cancellation section 22a having a closed ring shape, or to extinguish the light cancellation section 22a itself. Data logger.
The method according to claim 1 or 4,
Holographic data recording using a solid immersion lens, characterized in that the central portion of the beam located inside the photo-clearing section 22a becomes a signal beam, and the periphery of the beam located outside the photo-clearing section 22a becomes a reference beam. Device.
The method of claim 1, wherein the optical path forming means 20,
A phase difference of 1/4 wavelength is applied to the signal beam in the linear polarization state separated by the spatial light modulator 22 and the reference beam is converted into circular polarization to the optical means 30. A quarter wave plate (QWP, quarter wave length plate) 24 which is incident;
Holographic data recording device using a solid immersion lens, characterized in that comprising a.
The method of claim 1,
After focusing on the disk 90, the S-polarized light is separated from the beam reflected and returned in parallel with the path of incidence to the light receiving element such as a complementary metal-oxide semiconductor (CMOS) and a charge coupled device (CCD). A first beam splitter (BS) 23 for reflecting;
Holographic data recording apparatus using a solid immersion lens, characterized in that comprising a.
The method of claim 1, wherein the solid immersion lens 32,
A holographic data recording apparatus using a solid immersion lens, characterized in that provided between the objective lens 31 and the disk (90) of the objective lens system at intervals of more than 0nm and 20nm or less with the recording layer of the disk (90).
The method of claim 1 or 8, wherein the solid immersion lens 32,
And a refractive index such that the numerical aperture of the optical system including the objective lens system exceeds one.
The method of claim 1 or 2, wherein the light source means 10,
A red light irradiator 12 for irradiating a beam with a red laser having a wavelength λ = 633 nm;
Holographic data recording apparatus using a solid immersion lens, characterized in that comprising a.
The method of claim 10, wherein the optical path forming means 20,
A second beam splitter (BS) for reflecting the red laser irradiated from the red light irradiator 12 so as to travel in the same optical path as the optical path for data recording;
Holographic data recording apparatus using a solid immersion lens, characterized in that comprising a.
Using a spatial light modulator (SLM) 22, a beam irradiated from the light source means 10 is separated into a signal beam and a reference beam on the same optical path, and the light source means 10 and the disk Beam separation step to proceed to the (90) side;
Using a solid immersion lens (SIL) 32, the numerical aperture (NA) of the objective lens system (NA = nsinθ) is increased to 1 or more to focus on the recording layer of the disc 90. A beam reduction step of reducing the size (d = λ / NA) of the beam spot to be used; And
An overlapping recording step of recording data by focusing the signal beam and the reference beam whose size is reduced in the beam reduction step at the same point on the recording layer of the disc (90);
Including but not limited to:
The spatial light modulator,
On the path through which the beam passes, a recording method using a holographic data recording apparatus using a solid immersion lens, characterized in that for displaying a closed annular light canceling portion (22a) for separating and partitioning the cross section of the beam into a central portion and a circumferential portion. .
The method of claim 12,
A red light irradiation step of irradiating the red laser to the light path side for data recording by using the red light irradiator 12;
Using a second beam splitter (BS) 21 mounted on the optical path for data recording, red on the light source means 10 and the disk 90 side on the same optical path as the optical path for data recording. A red light adjusting step of switching a traveling direction of the laser; And
A focus position checking step of focusing a red laser incident on the light source means 10 and the disk 90 through the red light adjusting step to a recording position on the disk 90, and confirming and adjusting the recording position;
Recording method using a holographic data recording device using a solid immersion lens, characterized in that it further comprises.
The shape of the light canceling section 22a provided by the spatial light modulator (SLM) 22 is changed from a closed loop linear to a plane in which the inner region of the closed loop disappears to cancel the signal beam. Signal beam cancellation step;
Using the solid immersion lens (SIL) 32, the reference beam remaining through the signal beam erasing step is used, and the disk 90 with one or more numerical apertures (NA = nsinθ). A reference beam focusing step of focusing on the recording layer of the camera;
A beam splitter (BS) 23 is used to separate the S-polarized light from the reference beam focused on the recording position of the disk 90 and then returned in parallel with the same path as the incident path. Recording data extraction step; And
A data reproducing step of inputting the S polarized light extracted in the recording data extraction step into a light receiving element and outputting a reproduction signal from the reference beam reflected by the disc (90);
Playback method using a holographic data recording device using a solid immersion lens comprising a.

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