An optical system for holographic storage includes a reference light path, a signal light path, a servo light path and a reproduction light path. The reference light path and the signal light path contain a first Fourier lens and a second Fourier lens for transmitting reference light and signal light carrying data information, and adjusting the incident position and angle of the reference light and the signal light on a storage medium. The optical system includes a reference light objective lens for converging the reference light, a third Fourier lens for performing Fourier transformation on a signal light field, and a fourth Fourier lens for performing Fourier transformation on a reproduced signal light field to read the data information. The first Fourier lens, the second Fourier lens, the third Fourier lens, the fourth Fourier lens and the reference light objective lens is respectively a Fresnel lens or a meta lens.

An optical system for holographic storage includes a reference light path, a signal light path, a servo light path and a reproduction light path. The reference light path and the signal light path contain a first Fourier lens and a second Fourier lens for transmitting reference light and signal light carrying data information, and adjusting the incident position and angle of the reference light and the signal light on a storage medium. The optical system includes a reference light objective lens for converging the reference light, a third Fourier lens for performing Fourier transformation on a signal light field, and a fourth Fourier lens for performing Fourier transformation on a reproduced signal light field to read the data information. The first Fourier lens, the second Fourier lens, the third Fourier lens, the fourth Fourier lens and the reference light objective lens is respectively a Fresnel lens or a meta lens.

Provided is a method of manufacturing an optical disk having at least a cover layer, a first information recording surface, a first intermediate layer, a second information recording surface, a second intermediate layer, and a third information recording surface in order from a surface irradiated with a light beam on at least one side, wherein a numerical aperture of an objective lens that converges the light beam on any of the recording surface of the optical disk when information recording or information reproduction of the optical disk is performed is 0.91, standard value dk of each thickness from the surface to the first to third information recording surfaces is set on the premise of standard refractive index no, where k is 1, 2, 3, and a target value of each actual thickness from the surface to the first to third information recording surfaces is determined by a product of conversion coefficient g(n) depending on refractive index n from the first to third information recording surfaces, and standard value dk.

Provided is a method of manufacturing an optical disk having at least a cover layer, a first information recording surface, a first intermediate layer, a second information recording surface, a second intermediate layer, and a third information recording surface in order from a surface irradiated with a light beam on at least one side, wherein a numerical aperture of an objective lens that converges the light beam on any of the recording surface of the optical disk when information recording or information reproduction of the optical disk is performed is 0.91, standard value dk of each thickness from the surface to the first to third information recording surfaces is set on the premise of standard refractive index no, where k is 1, 2, 3, and a target value of each actual thickness from the surface to the first to third information recording surfaces is determined by a product of conversion coefficient g(n) depending on refractive index n from the first to third information recording surfaces, and standard value dk.

[Object] To prevent the occurrence of stuck without increasing the number of components and also to restore thread engagement of a rack with a lead screw to a normal condition. [Solution] Provided is an optical pickup including: a light source; an objective lens; an optical element; and an optical element driving device. The optical element driving device includes a lead screw having a threaded engagement portion with a thread groove formed in the threaded engagement portion, a drive unit configured to allow the lead screw to rotate, a thrust bearing configured to support an end portion of the lead screw on a side opposite to the drive unit in an axial direction of the lead screw, and a rack having a plurality of first tooth portions provided spaced apart in the axial direction to be threadably engaged with the threaded engagement portion and a second tooth portion provided closer to the thrust bearing in the axial direction than the first tooth portion to be threadably engaged with the threaded engagement portion, the first tooth portion and the second tooth portion being positioned on opposite sides across the lead screw, the rack being moved in the axial direction with a rotation of the lead screw. The lead screw includes a non-threaded engagement portion formed at the end portion of the lead screw on the thrust bearing side, the non-threaded engagement portion having no thread groove.