Mixed-valence ion-doped PVA as potential materials for real-time holography

摘要

Mixed valence ion doped polymers are potential materials for the real time holography. We review the intimate mechanisms imposing suitable optical properties in Fe:PVA, stressing on the main role played by the Fe ions. Under the UV exposure, both the refractive index and the absorption coefficient are changing due to a local electron transfer from the PVA matrix to the Fe$+3$PLU$/ ions. The absorption coefficient proved to be dependent on a new-formed low spin Fe$+2$PLU$/ state whereas the refractive index and the absorption coefficient are changing due to a local electron transfer from the PVA matrix to the Fe$+3$PLU$/ ions. The absorption coefficient proved to be dependent on a new-formed low spin Fe$+2$PLU$/ state whereas the refractive index is related to the total content of the high spin Fe$+2$PLU$/ state. The diffraction efficiency data are explained in terms of the Fe$+2$PLU$//Fe$+3$PLU$/ ratio. Additional data concerning the electron transfer in Sn:PVA thin films are also discussed.