3D optical data storage can benefit from the non-linear process of two-photon absorption (TPA). If some chromphores with large TPA cross section are introduced into the diarylethene to enhance its two-photon absorptivities, it is expected to be good recording media for 3D optical data storage. The authors have synthesized four diarylperfluorocyclopentene (DPFCP) derivates for the purpose of developing two-photon 3D optical data storage. The nonlinear two-photon absorption (TPA) properties of the compounds were examined, and the reaction and excited state relaxation dynamics after two-photon excitation were investigated. The TPA cross sections of 2-position DPFCPs were measured by means of TPIF (two-photon induced fluorescence) method, and the highest is 48×10-50cm4•s•photo-1•molecule-1. The compounds were successfully applied in two-photon 3D optical data storage based on single beam two-photon femtosecond writing and one-photon fluorescence reading. Ten-layer clear images on DPFCP/PMMA film were obtained, and the data storage density is high to 2.0×1011 bits/cm3.
The novel photochromism, diarylethene derivatives, 1,2-bis(2,5-dimethyl-thien-3-yl)perfluoro cyclopentene (1a) and 1,2-bis(2-methyl-5-carbonylphenyl)-thien-3-yl) perfluorocyclo pentene(2a) were synthesized. And the PC discs of these two diarylethenes were prepared by spin-coating and vacuum evaporating method. To some extent, the high density recording was carried out the multi-wavelength and multi-level optical storage system. On the PC disc, single-wavelength and eight-level recording was realized by 2a, and two laser beams of 532nm and 650nm were used in two-wavelength eight-level recording and readout simultaneously. The results show that the reflectivity differences between the recording region and unrecording region is greater than 50%. The creation is that the two-wavelength and four-step optical recording on the PC disc achieved first time.
In this paper, diarylethene derivative, 1,2-bis(2-methyl-5-N,N-dimethylaminophenyl)-thien-3-yl) perfluorocyclopentene (BMDTP) was synthesized. And the PMMA film of 10μm thickness of BMDTP was fabricated by spin-coating method. The maximal UV-Visible absorption of amorphous PMMA film is 634nm. And the reflective index modulation(Δn) is 2.14×10-3 between the open- and close-rings form. On the PMMA film, ten gratings of hologram are recorded in one volume by angle multiplexing. Therefore, the diarylethene is a promising material for rewritable volume holographic optical storage.
The diarylethene may undergo photochemical ring-closing reaction and both photochemical and electrochemical ring-opening reaction. Irradiation of the open form with UV light results in essentially quantitative photocyclization to the deeply colored form. The dithienylcyclopentene derivative in their ring-closed forms can undergo ring-opening upon electrochemical oxidation.