This project aims to study basic processes associated with the photorefractive effect in novel hybrid inorganic-nanocrystals containing polymer-dispersed-liquid-crystal nanocomposites, where the various necessary processes take place in different nanodomains. This provides the opportunity to combine the merits of the two widely different classes of materials, inorganic and organic, to optimize the various processes. Fundamental processes of photo-charge generation and charge-carrier dynamics as well as the space charge field induced electro-optic orientation (birefringence) of the liquid crystal nanodroplets will be studied. The goal is to produce spectrally tunable high performance photorefractive nanocomposites. The kinetics of grating growth and decay and the effect of various liquid crystal parameters on the photorefractive efficiency will be investigated. The project will expose graduate students to state-of-the art nanocrystals synthesis and sample fabrication techniques. Also, they will learn about different cutting-edge characterization schemes including photoconductivity, time-of-flight mobility, degenerate four wave mixing and two beam coupling experiments requiring the use of various types of laser sources. %%% Photorefractive processes utilize conversion of light energy to electrical charges and their subsequent movement. They find important applications in optoelectronic devices that are useful for optical amplification and beam improvement for telecommunications, as well as for correction of beam distortion in light based radar. In order to produce the improvement in performance necessary for these applications, significant gains in the photogeneration of charges and their speed are needed. These improvements will also benefit the development of highly efficient solar cells where light can be transformed more efficiently to electricity. This proposal utilizes nanotechnology to combine the merits of two widely different classes of materials, organic and inorganic, to produce hybrid media and separate the various processes in different nanosize regions. By a combination of the proposed techniques, a fundamental understanding of these processes in this hybrid media will permit their optimization separately. A valuable part of the proposed research will be to provide broad based training of graduate students to enhance the skilled workforce needed in this vital area of photonics. This research underpins advances in a number of energy related technologies, such as solar energy, that address important societal needs. Students trained in these areas will compete effectively in high technology job markets.
