High-density Optical Information Storage Technology Based On Cylindrical Vector Beam

With the development of the Internet and other fields,human society has entered the era of big data together with the dramatical growth of massive data.The information storage field has met development opportunities and severe challenges under such a circumstance.Traditional storage methods are difficult to meet the needs of massive information storage in the era of big data.Therefore,it is urgent to develop a new generation of information storage technology.The development of the optical information storage technology makes it one of the effective solutions.Since light has many physical dimensions,such as amplitude,phase,angular momentum,polarization,etc.,these physical dimensions can be utilized for information multiplexing storage to greatly increase the number of multiplexing channels and thus boost storage capacity,which has broad application prospects in meeting the needs of massive information storage.Conventional optical information storage technologies are mostly based on the interaction between Gaussian beam and gold nanorods,using the wavelength and polarization dimensions of Gaussian beam combined with three-dimensional space to realize multi-dimensional optical storage.Compared with Gaussian beam,cylindrical vector beam has more abundant polarization characteristics.This study intends to use these characteristics to realize high-density optical information storage based on the interaction of cylindrical vector beam and gold nanorods.The main contents of this paper are as follows:(1).By using the Jones matrix calculation method,the mathematical expression of segmented cylindrical vector beams is obtained by combining the Jones matrix of cylindrical vector beam and the polarizer together with the existing tight focusing theoretical research of vector beam,the tight focusing process of segmented cylindrical vector beams is derived and the corresponding tight focus result are obtained.We draw the electric field and vector field distribution of segmented cylindrical vector beam in the focal plane,analyzes its feasibility and advantages in the field of optical storage.We then draw a cross-sectional view along the propagation direction to analyze its propagation characteristics.(2).A simplified coupled disordered gold nanorod model is proposed,which is convenient for simulating the complex characteristics of the coupled disordered gold nanorod system by adjusting the parameters of the model.The finite-difference time-domain method was used to calculate the interaction between segmented cylindrical vector beam and the coupled disordered gold nanorod model.By analyzing the corresponding response characteristics of the model,the theoretical feasibility of light information multiplexing storage based on the interaction of segmented cylindrical vector beam and the coupled disordered gold nanorod was verified and the influence of coupling strength among gold nanorods are discussed.Finally,the theoretically feasible wavelength and polarization multiplexing interval are also obtained.(3).We briefly introduce the pre-experiment preparation work such as gold nanorod sample preparation,experimental optical system design and construction,and binary information preparation.We have proved through experiments that the cylindrical vector beam can be used for optical information multiplexing and storage,and by optimizing parameters such as laser power and wavelength multiplexing interval,we have obtained multiplexed storage results with a low bit error rate.In addition,we experimentally proved high-density optical information storage based on segmented cylindrical vector beam,exploring the limit of the number of multiplexing channels in the polarization dimension of this technology,the related experimental results refreshed the record of the storage areal density of the multi-dimensional optical data storage technology based on gold nanorods,reaching 3Gbits/cm~2.Finally,the further development of this technology is prospected.