A two-photon single-laser optical data storage system in a multilayer structure

In this work, a two-photon recording system in a 50-layer structure is designed with each recording layer containing 4.7 GB of data, similar to the capacity of a singlelayer digital versatile disc, with the total capacity becoming 235 GB/disc. By the use of a single-laser system to realize recording and reading, a multilayer disc structure is applied in which the groove structure is set on the substrate for servo control; the laser is separated by a polarized beam splitter (PBS) into two parts, one for recording and the other for servo control in the optical system. The simulation results show the feasibility of high-density optical data storage using a single laser in a multilayer structure. The experimental platform is set up in which the focus error signal is verified.