Polychromatic and polarized multilevel optical data storage
Optical multiplexing is of great importance in information processing, and offers the opportunity to dramatically increase the capacity of information systems. For example, multiplexing among different physical dimensions of light is regarded as an efficient means to substantially increase the capacity of optical data storage (ODS). Alternatively, the capacity can also be increased by multilevel coding. In this paper, we report on the combination of multiplexing among multiple physical dimensions and multilevel coding simultaneously to dramatically boost the capacity of ODS. The physical mechanism relies on the excitation power dependent thermal reshaping of the ODS medium mediated by wavelength and polarization sensitive random hot spots in a volume of coupled disordered gold nanorods (GNRs). The resulting electric field intensity varies drastically inside the focus spot of a laser beam when different combinations of polarization and wavelength are used. Therefore, different hot spots can be selectively activated and encoded by controlling the power of the recording beam, facilitating the realization of the polychromatic and polarized multiplexing of multilevel coding in the disordered plasmonic structure. Our results might find applications in high capacity optical data storage, watermarking, etc.