Realizing high density optical data storage by using orbital angular momentum of light beam

The orbital angular momentum (OAM) states can be used to construct a high-dimensional Hilbert space, which implies higher data density when applied in data storage. This work proposes a method to realize high density optical data storage by using OAM of light beam, with the encoded area illuminated by a light beam with certain OAM resulting in distribution of power in the OAM states (the spiral spectrum or OAM spectrum), and detection of the power distribution conducing to its decoding. A quadrant staircase structure (QSS) used as an encoded element can realize 57 different states, and it is expected to enhance the data density 6 times as high as the conventional method.