A radial servo control device for a super-resolution optical disc includes an excitation light source, a servo light source, an integrated optical path, focusing units, a servo light detecting unit and a drive control unit; the drive control unit presets N detection error reference values with respect to each guide layer trench irradiated by servo light, and controls corresponding positions of the focusing units in N data tracks below each guide layer trench according to a comparison result between a detection result of servo reflected light and the detection error reference values. The device is applicable to a variety of super-resolution optical discs on the basis of stimulated radiation loss microscopy technology, a two-photon absorption technology, and the like, and achieves accurate radial servo control of super-resolution data tracks (<100 nm) without reducing the wavelength of servo light and the width of guide layer trenches.

One example provides a system for reading birefringent data. The system comprises one or more light sources, a first polarization state generator positioned to generate first polarized light from light of a first wavelength band output by the one or more light sources, a second polarization state generator positioned to generate second polarized light from light of a second wavelength band output by the one or light sources, an image sensor configured to acquire an image of the sample region via the first polarized light and the second polarized light, a polarization state analyzer disposed between the sample region and the image sensor, a first bandpass filter configured to pass light of the first wavelength band onto the image sensor, and a second bandpass filter configured to pass light of the second wavelength band onto the image sensor.

One example provides a computer-implemented method for reading data stored as birefringence values in a storage medium. The method comprises acquiring an image of a voxel of the storage medium, applying a first low-pass filter with a first cutoff frequency to the image of the voxel to obtain a first background image, applying a second low-pass filter with a second cutoff frequency to the image of the voxel to obtain a second background image, the second cutoff frequency being different than the first cutoff frequency, determining an enhanced background image from the first background image and the second background image, determining birefringence values for the enhanced background image, determining birefringence values for the image of the voxel, and correcting the birefringence values for the image of the voxel based upon the birefringence values for the enhanced background image.

One example provides a system for reading birefringent data. The system comprises one or more light sources, a first polarization state generator positioned to generate first polarized light from light of a first wavelength band output by the one or more light sources, a second polarization state generator positioned to generate second polarized light from light of a second wavelength band output by the one or light sources, an image sensor configured to acquire an image of the sample region via the first polarized light and the second polarized light, a polarization state analyzer disposed between the sample region and the image sensor, a first bandpass filter configured to pass light of the first wavelength band onto the image sensor, and a second bandpass filter configured to pass light of the second wavelength band onto the image sensor.

A detection apparatus determines whether a recording layer of an optical disc is at a focal point of an objective lens. The detection apparatus includes an objective lens, a beam splitter, a reflector, a detector, and a servo controller. The reflector and the detector are disposed opposite to each other on two sides of an optical axis of the objective lens, and a normal line of the reflector is perpendicular to the optical axis. The beam splitter is disposed between the reflector and the detector and is located on the optical axis. The servo controller is connected to the detector.

One example provides a system for reading birefringent data. The system comprises one or more light sources, a first polarization state generator positioned to generate first polarized light from light of a first wavelength band output by the one or more light sources, a second polarization state generator positioned to generate second polarized light from light of a second wavelength band output by the one or light sources, an image sensor configured to acquire an image of the sample region via the first polarized light and the second polarized light, a polarization state analyzer disposed between the sample region and the image sensor, a first bandpass filter configured to pass light of the first wavelength band onto the image sensor, and a second bandpass filter configured to pass light of the second wavelength band onto the image sensor.

The present invention relates to a holographic data storage device with a single-arm structure, and belongs to the technical field of optical holographic storage. According to the device disclosed in the present invention, a part of a reference arm and a part of a signal arm are integrated together to form a single-arm structure, which can not only reduce the number of optical and mechanical elements, but also reduce the system volume and cost without degrading performance. In addition, a signal beam and a reference beam share the same relay lens, so that the impact of environmental interference on the two beams is equal, and the stability of the entire system is improved.

The present invention relates to a holographic data storage device with a single-arm structure, and belongs to the technical field of optical holographic storage. According to the device disclosed in the present invention, a part of a reference arm and a part of a signal arm are integrated together to form a single-arm structure, which can not only reduce the number of optical and mechanical elements, but also reduce the system volume and cost without degrading performance. In addition, a signal beam and a reference beam share the same relay lens, so that the impact of environmental interference on the two beams is equal, and the stability of the entire system is improved.

The present invention relates to a holographic storage device and method for simultaneously recording and reading on two sides, and pertains to the technical field of optical holographic storage. The device and method disclosed in the present invention use a characteristic that orthogonal light would not interfere with each other and a Bragg selectivity characteristic for holographic storage, and use two optical heads to constitute two interference fields orthogonal in polarization directions on two sides of a same position of a holographic storage medium, so as to perform two-path simultaneous recording and reading on a hologram. The device and method provided in the present invention implement two-path parallel recording and reading of holographic storage, and combine shift multiplexing and circumferential rotation multiplexing, thereby improving the speed of an information data recording and reading process while increasing a capacity of the holographic storage.

The present patent relates to a parallel reproducing holographic disk reading method and device, and belongs to the technical field of optical holographic storage. According to an angle-shift multiplexing method included in the present patent, multiplex recording is performed by simultaneously changing an incident angle of a reference light and moving a medium with a fixed angle change amount and a fixed shift amount. In this method, the reference light can be split for incidence, and then holograms in different units can be simultaneously reproduced. According to the method disclosed by the patent, a recorded hologram can be read and written in real time, and a recorded signal can be checked under a condition of satisfying a response time required by the medium.