Photopolymerizable nanocomposite photonic materials and their holographic applications in light and neutron optics.

We present an overview of recent investigations of photopolymerizable nanocomposite photonic materials in which, thanks to their high degree of material selectivity, recorded volume gratings possess high refractive index modulation amplitude and high mechanical/thermal stability at the same time, providing versatile applications in light and neutron optics. We discuss the mechanism of grating formation in holographically exposed nanocomposite materials, based on a model of the photopolymerization-driven mutual diffusion of monomer and nanoparticles. Experimental inspection of the recorded grating's morphology by various physicochemical and optical methods is described. We then outline the holographic recording properties of volume gratings recorded in photopolymerizable nanocomposite materials consisting of inorganic/organic nanoparticles and monomers having various photopolymerization mechanisms. Finally, we show two examples of our holographic applications, holographic digital data storage and slow-neutron beam control.

Effects of symbol modulation coding on readout fidelity of shift-multiplexed holographic digital data page storage in a photopolymerizable nanoparticle-(thiol-ene)polymer composite film.

We report on shift-multiplexed holographic storage of 250 digital data pages in a photopolymerizable SiO2 nanoparticle-polymer composite film being capable of step-growth thiol-ene polymerization in the green. Various two-dimensional symbol modulation codes for the digital data page format were employed to examine the dependence of the readout fidelity on modulation coding schemes. It is found that, as compared to 1:2 and 2:4 modulation codes, higher-order 5:9, 9:16, and 13:25 modulation codes possessing reduced white rates and higher coding efficiencies give lower symbol-error rates of ~1×10⁻³ and higher signal-to-noise ratios (>4).

Shift-multiplexed holographic digital data page storage in a nanoparticle-(thiol-ene) polymer composite film.

We demonstrate shift-multiplexed holographic storage of 180 digital data pages with low symbol-error rates in a thick (250 µm) SiO2 nanoparticle-polymer composite film using step-growth thiol-ene photopolymerization. A two-dimensional 2:4 modulation code was employed for formatting digital data pages in order to reduce the average intensity of code block without decreasing the coding efficiency. This study clearly shows the feasibility of the thiol-ene based nanoparticle-polymer composite system as a holographic data storage medium.