Optical Storage And Operation Based On Photostimulated Luminescence

In the information age,the inheritance of human civilization depends on the storage of digitalized data,including characters,images,audios and videos.Owing to the explosive growth of data,existing storage methods are increasingly difficult to meet demand.Currently,there are three primary storage technologies:magnetic storage represented by hard disk drives（HDDs）,semiconductor storage represented by flash memories and optical storage represented by compact disks.In comparison to others,optical storage shows the outstanding advantages of a large capacity,fast response,long lifetime and low energy consumption.Significantly,optical storage can be used as a platform for optical operation in the same material to realize ultrahigh-speed parallel data processing.It has broad application prospects.Generally,at least three conditions are required to integrate the two functions of storage and operation:two discrete,stable states that represent logical 1 and 0,switch between the two states under optical stimulations;and light-matter interaction relevant to binary operations.According to these conditions,optical storage based on photostimulated luminescence（PSL）is exactly an ideal choice.Therefore,it is generally considered the most promising advanced storage technology.PSL optical storage materials should store energy steadily after ultraviolet light or near UV light,and release energy in the form of visible light after visible or infrared laser stimulation.Moreover,in order to achieve long-term storage of data,the PSL materials have to contain isolated and deep traps.In this work,the trap depth of Lu₃Al₅O₁₂:Ce³⁺fluorescent powder which is selected as the research object has reached 1.34 e V.Through the study of the writing,reading,storage and erasure properties of Lu₃Al₅O₁₂:Ce³⁺material,254 nm ultraviolet light is established as the information writing light source,low-power 808 nm infrared laser as the information reading stimulation light source,and high-power 808 nm infrared laser as the information clearing light source.The experimental results show that the material can achieve information writing and clearing in a short time,information storage for a long time and stable information reading.It is revealed that Lu₃Al₅O₁₂:Ce³⁺is an excellent PSL optical storage material.Meanwhile,the material meets the basic requirements of integrated storage and operation functions,which makes it possible to use photons instead of electrons to realize optical computing on the optical storage platform.Based on the PSL characteristics of Lu₃Al₅O₁₂:Ce³⁺material and the integration of optical storage and optical operation,it demonstrates that Boolean logic operations,binary operations,and matrix multiplications can be optically performed based on PSL.Accordingly,two typical examples are presented to show how to solve complicated problems by PSL-based optical operation.