2. Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, Guangdong 510632, China;
3. Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou, Guangdong 510631, China
Overview: The digital data created by human being grows exponentially in time. Conventional magnetic storage technologies are difficult to meet this challenge. It means that new storage technologies with higher capacity, higher security and longer storage time should be developed to meet such challenge in information era. With the invention of lasers and the rapid development of nanotechnology, optical data storage technology based on light-matter interaction was shown to be a potential solution to this end. However, commercial optical data storage technologies are currently difficult to meet the increasing requirement for big data storage. Researchers are going to explore new means to further increase storage capacity to meet the growing requirements for massive data storage. For example, the capacities of multi-dimensional optical data storage, super-resolution optical data storage and multi-level optical data storage technologies were demonstrated to be much larger than traditional optical storage technologies. Herein, we review the recent progresses of multi-dimensional optical data storage, super-resolution optical data storage and multi-level optical data storage technology, with the focus on multi-dimensional optical storage technology. The gold nanorod (GNR) shows unique properties of a longitudinal surface plasmon resonance. By using the wavelength and polarization dependent responses of GNRs, five-dimensional (the wavelength and polarization of light and the three spatial dimensions) optical data storage has been demonstrated with TB scale storage capacity for the same volume of a DVD disc. In order to increase the number of information channels in the focused spot volume for this kind of optical storage technology, the intuitive approach is to increase the number of GNRs per unit volume, which inevitably increase the coupling strength among GNRs. Therefore, hot spots will be formed in the small gaps among GNRs. As a result, rather than using the response of a single GNR, the polarization and wavelength sensitivity of random hot spots in a volume GNR assembly can be used to encoded information and realize multi-dimensional data storage. At the same time, the plasmonic coupling among GNRs can also significantly enhance linear absorption and two-photon induced luminescence of the GNRs. As a result, five-dimensional optical data storage by encoding random hot spots of a volume GNR can be realized by using an ultralow energy. This technology improves significantly both the quality and capacity of optical data storage. We also provide outlooks for how to further increase the capacity of the five dimensional optical data storage and our future prospective of this technology.