JPWO2020263927A5 - - Google Patents

Claims (21)

An optical system for reading beams of data channels from a moving single-layer or multilayer three-dimensional optical information storage medium, comprising:
An optical system comprising at least one optical element characterized in that it limits the field of view (FOV) of said reading beam on an associated image plane to between 0.3 and 2 Airy disk diameters in a first direction. 2. The method of claim 1, wherein the at least one optical element limits the FOV of the read beam by limiting the FOV on the read photodetector to 0.3-2 Airy disk diameters in the first direction. Optical system as described. the at least one optical element limits the FOV of the read beam by limiting a data spot size focused onto the core of an optical fiber to 0.3-2 Airy disk diameters in the first direction; 3. The optical system of claim 1 or 2, wherein said optical fiber couples said read beam to an associated read photodetector. The optical system of any one of claims 1-3, wherein the at least one optical element limits the FOV of the reading beam to 0.3 to 1 Airy disk diameter in the first direction. The at least one optical element is
limiting the FOV on the read photodetector to 0.3 to 2 Airy disk diameters in the first direction;
limiting the data spot size focused at the end of the optical fiber to between 0.3 and 2 Airy disk diameters in the first direction. The optical system described in . 2. The optical system of claim 1, wherein said at least one optical element comprises an aperture in an optical path between said optical information storage medium and a reading photodetector. the at least one optical element substantially collimating the reading beam and focusing the substantially collimated reading beam into an optical fiber for coupling to an associated reading photodetector; 2. The optical system of claim 1, including a second lens. An optical system for reading beams of data channels from a moving three-dimensional optical information storage medium, comprising:
a reading photodetector;
an optical path between an objective lens and the readout photodetector;
The optical system wherein the read photodetector has an active area sized to limit a field of view (FOV) of the read beam on the active area to 0.3 to 2 Airy disk diameters in a first direction. 9. The optical system of claim 8, wherein the active area of the read photodetector is sized to limit the FOV of the read beam to 0.3 to 1 Airy disk diameter in the first direction. 10. The optical system of claim 9, wherein the FOV of the reading beam is restricted in a second direction to a different extent than the first direction. 3. The claim of claim 1, wherein: (a) the three-dimensional optical information storage medium is one of reflective and fluorescent; and (b) the reading beam is one of reflective and Stokes shift fluorescent. 11. The optical system according to any one of 8 to 10. a focus error signal (FES) subsystem having two optical fibers used for differential confocal FES detection from said optical information storage medium, for generating a focus error signal (FES) from said optical information storage medium; 12. The optical system of any one of claims 8-11, further comprising. An optical system for detecting optical signals from a moving three-dimensional optical information storage medium, comprising:
at least one lens for receiving and substantially collimating an optical signal and focusing the substantially collimated optical signal into an optical fiber having a core diameter of 1-20 micrometers;
the at least one lens and the optical fiber are configured, spaced and positioned with respect to each other and cooperate with each other to provide an A value between 0 and 10 according to the formula:

where a ₀ = pupil of said at least one lens, d = distance from said at least one lens to said optical fiber, r ₀ = fiber core radius, λ is wavelength of said optical signal, a ₀ /d is said An optical system defining the numerical aperture (NA) of at least one lens, wherein D _A in Equation 1 is the Airy disk diameter given by 1.22λd/a ₀ =1.22λ/NA. 14. The optical system of claim 13, wherein the at least one lens and the optical fiber cooperate to increase both planar and axial digital data density in the three-dimensional optical information storage medium. The at least one lens and the optical fiber cooperate to reduce the layer spacing by allowing the space between active layers to be reduced, thereby providing axial digital data in the three-dimensional optical information storage medium. 14. The optical system of claim 13 , which increases density. 16. The optical system of any one of claims 13-15 , further comprising at least one chromatic or spherochromatic aberration corrector correcting over the spectral bandwidth of the optical signal. 17. Any of claims 13-16 , wherein the at least one lens comprises first and second lenses for receiving and substantially collimating the optical signal and for focusing the substantially collimated optical signal into the optical fiber. The optical system according to item 1. the at least one lens includes first and second lenses for receiving and substantially collimating the optical signal and focusing the substantially collimated optical signal into the optical fiber;
the optical system further includes at least one of a diffraction aberration corrector, a chromatic aberration corrector, and a spherochromatic aberration corrector that correct over the spectral bandwidth of the optical signal;
18. An optical system according to any one of claims 13-17 . 19. The optical system of any one of claims 13-18 , further comprising at least one phase plate window (W) for adjusting the focus of the optical signal between the objective lens and said at least one lens. 20. The optical system of any one of claims 13-19 , further comprising at least one phase asymmetric beam splitter for asymmetrically splitting the optical signal between an objective lens and the at least one lens. 4. The optical system of claim 3, wherein the optical fiber provides coherent detection in reflectance type media.