Abstract: A spiral phase plate, according to one embodiment, for generating a Laguerre Gaussian beam by reflecting an incident beam emitted from a light source, may comprise: a first quadrant area in which the step height increase rate per unit angle decreases progressively in one direction from the point with the lowest step height to the point with the highest step height; and a second quadrant area in which the step height increase rate per unit angle increases progressively in the one direction.

Abstract: A storage device and a storage system including the same are provided. The storage device includes a nonvolatile memory with a valid page and a free page; a temperature sensor configured to sense a temperature of the nonvolatile memory; and a storage controller configured to implement: a patrol read module configured to read valid data stored in the valid page and identify a number of errors in the read valid data according to a set time period, and a retention module configured to, based on the temperature or the number of errors, read the valid data stored in the valid page, and write the valid data to the free page while controlling a threshold voltage distribution width corresponding to a value of the valid data written to the free page.

Abstract: A storage device and a storage system including the same are provided. The storage device includes a nonvolatile memory with a valid page and a free page; a temperature sensor configured to sense a temperature of the nonvolatile memory; and a storage controller configured to implement: a patrol read module configured to read valid data stored in the valid page and identify a number of errors in the read valid data according to a set time period, and a retention module configured to, based on the temperature or the number of errors, read the valid data stored in the valid page, and write the valid data to the free page while controlling a threshold voltage distribution width corresponding to a value of the valid data written to the free page.

Abstract: A storage device and a storage system including the same are provided. The storage device includes a nonvolatile memory with a valid page and a free page; a temperature sensor configured to sense a temperature of the nonvolatile memory; and a storage controller configured to implement: a patrol read module configured to read valid data stored in the valid page and identify a number of errors in the read valid data according to a set time period, and a retention module configured to, based on the temperature or the number of errors, read the valid data stored in the valid page, and write the valid data to the free page while controlling a threshold voltage distribution width corresponding to a value of the valid data written to the free page.