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.

A wireless device according to one aspect of the present invention includes an antenna, a focuser, and an absorber. The focuser includes a first and a second region. One of the regions transmits radio waves, and the other blocks them or changes their phase. In a plan view from the antenna, the shape of the first region is a circle and the shape of the second region is an annular ring with an inner diameter equal to the diameter of the first region. The antenna is on the center axis of the circle. A part of the absorber is present between a first plane where the antenna is present and a second plane on which the second region is present. The absorber is present at a position away from the antenna by the outer circumference of the annular ring or longer in a direction perpendicular to the axis.

A wireless device according to one aspect of the present invention includes an antenna, a focuser, and an absorber. The focuser includes a first and a second region. One of the regions transmits radio waves, and the other blocks them or changes their phase. In a plan view from the antenna, the shape of the first region is a circle and the shape of the second region is an annular ring with an inner diameter equal to the diameter of the first region. The antenna is on the center axis of the circle. A part of the absorber is present between a first plane where the antenna is present and a second plane on which the second region is present. The absorber is present at a position away from the antenna by the outer circumference of the annular ring or longer in a direction perpendicular to the axis.