Volume Holographic Storage Of Photochromic Diarylethene-doped PMMA Films

Volume holographic storage is one of the most potential storage techniques inthe future due to its high redundancy, parallel transmission, high density, and contentaddressability. Furthermore, the rewritable and nonvolatile volume holographicstorage has been the great white whale of technology research. Because the suitablerecording material is the key to the development of the rewritable holographic storage,the researchers from many countries are developing the commercial material. Thephotochromic diarylethene is a good candidate material for the application inrewritable holographic storage for its fatigue resistance and thermal irreversibility.Therefore, in this dissertation the applications of photochromic diarylethene inrewritable holographic data storage are investigated and the corresponding contentsare as follows.Firstly, the dependence of the performance of the rewritable volume holographicstorage on the properties of photochromic diarylethene is investigated. A model todescribe real-time grating formation in photochromic diarylethene-doped PMMA thinfilms is introduced based on photochromic chemicals reaction and the coupled-wavetheory. The model is validated by comparing its predictions with the experimentalresults.Secondly, some photochromic diarylethene are found to be sensitive to polarizedlight in our experiments. Different polarized light will induce its anisotropy, whichincludes dichroism and birefringence. To our knowledge, polarization multiplexing isfirstly applied in photochromic diarylethene. Moreover, a novel technique oforthogonal polarization dual-channel volume holographic storage is presented tosimultaneously record two orthogonally polarized holograms, which are retrievedwith negligible inter-channel crosstalk independently and synchronously. This designimproves storage density and the speed of input/output data in volume holographicstorage. Additionally, the technique can be combined with other multiplexingmethods such as angle multiplexing, shift multiplexing, peristrophic multiplexing.Finally, several methods are proposed to realize the nonvolatile readout based onthe properties of photochromic diarylethene. The corresponding analysis andexperimental results are presented.