Holographic Properties Of Fe₃O₄-nanoparticle Dispersed Acrylate Photopolymer

Optical polymer system caused wide attention due to its high sensitivity, low cost, and a wide range ofapplications such as optical holographic storage, the manufacture of optical components and opticalcommunication, etc. The problem is the high refractive index modulation and crumple phenomenonappeared at the same time. In order to improve the refractive index modulation and increase thedimensional stability, Holographic recording characteristics of the unmodified and modified by sodiumcitrate Fe3O4-nanoparticles dispersed in conventional organic photopolymers are studied. The hybridphotopolymer exist the mutual diffusion process and anti-wrinkle effect in our experimental system isverified.This article mainly includes the following several aspects:1. The unmodified Fe3O4nanoparticles were fabricated by the chemical precipitation method, on thebasis of the chemical precipitation method we modified Fe3O4nanoparticles by sodium citrate. Using X-raydiffraction instrument test the preparation of nanoparticles, proved the Fe3O4nanoparticles are relativelypure, and there is no other impurities generated. According to Scherrer’s formula, the average graindiameter15nm can be estimated by the each half-height peak width and the Bragg angle.2. We doped the unmodified/modified Fe3O4nanoparticles into photopolymer uniformly and tested theholographic recording characteristics. The results showed that doped with modified by sodium citrateFe3O4nanoparticle is more advantageous to improve the holographic performance.We speculate that this isdue to the better dispersion and stability of Fe3O4nanoparticles coating with sodium citrate.3. Four particle size of Fe3O4nanoparticles were manufactured by controlling the concentration offerric citrate, respectively is8.8nm,15nm,22nm and30nm. Different particle size Fe3O4nanoparticleswere dispersed into the organic photopolymer samples at different doping concentration, the holographicparameter of each samples was tested and analysis by stokes-Einstein relation, Rayleigh scatteringformula and the square wave particle size formula. Results showed that the maximum refractive indexmodulation of photopolymer doping with the optimal doping particle size15nm under the optimal dopingconcentration1.12×10-3mol/l was increased to2.038×10-3, the shrinkage rate was reduced to0.8%. 4. The analog holographic storage and digital holographic storage were experimented on the optimizedphotopolymer samples. The experimental results show that the diffraction reconstructed image was clear,signal to noise ratio and bit error rate of the data page within the acceptable range, this shows that thematerials of photopolymer doped with Fe3O4nanoparticles is expected to be applied in high densitydigitized holographic storage.