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A microperiodic structure composed of polymer and liquid crystal (LC) phases, called holographic polymer dispersed LC, is fabricated by a photo-induced phase separation technique using LC composites with different physical properties, such as refractive indices and clearing points. Effects of thermal modulation on diffraction properties of LC composite gratings are experimentally investigated in the viewpoints of polarization and temperature dependences. The diffractions based on the change of refractive index induced by the nematic--isotropic transition of LCs with the increase of temperature are applied for a holographic image reconstruction. [c] 2010 Optical Society of America OCIS codes: 090.2900, 160.3710, 160.5470.

The surface plasmon spectra (SPR) spectra of silver nanoparticles that were fabricated on a thermochromatic metal oxide, VO2, that exhibits a reversible metal-semiconductor phase transition at nearly 56 degrees Celsius is discussed. Further than SPR band the spectral line shape of silver particles were dominated by the imaginary part of the dielectric function of VO2.

We have studied the diffuse reflection properties of ceramics in the presence of dielectric thin films on the surface. A simple optical model was proposed in which interference effects in a thin film were considered for light scattered out of a ceramic in various directions. Measurements were performed on angle-resolved reflection spectra of a thin-film-coated alumina ceramic in the case of normal incidence. They showed that the presence of the thin film on the ceramic's surface modified the angular distributions of scattered radiation from that of a bare ceramic, which suggested a way to tailor the scattering properties of a diffuse reflector as needed. OCIS codes: 120.5700, 290.1990, 310.1620, 230.0250.

The spectral complex optical constants in the visible and the near-infrared region of V[O.sub.2] and [V.sub.1-x][W.sub.x][O.sub.2] films deposited on glass substrates were determined from observed reflectance and transmittance spectra for which the least-squares method was used. In the metallic phase, the optical properties were characterized by the Drude model in wavelength regions longer than 750 nm.

High-resolution spectra from 20 to 200 cm to the -1 for temperatures from 10 to 300 K give interference fringes that cannot be fitted by previous analysis in terms of four Lorentz oscillators. Parameters in the theory are revised to give a better fit both to the far IR and to the reststrahlen spectra.

Mg(1-y)Ca(y)H(x) (0.03≤y≤0.17) alloy thin films covered with thin Pd were hydrogenated using 4% H(2) in Ar under atmospheric pressure at room temperature. The complex dielectric functions (ε=ε(1) + iε(2)) in the range of 0.75 to 5.0 eV of these hydrides were evaluated with spectroscopic ellipsometry. The imaginary part of the dielectric function ε(2) was composed of one Drude and three Lorentz oscillator terms whose peak positions were about 1.2 eV (L(1)), 2.8 eV (L(2)), and 5.2 eV (L(3)). The L(3) term observed in all hydrides is attributed to optical absorption of MgH(2) with E(g)=5.16 eV. The Drude term, which may be due to unhydrogenated Mg-metal, was observed in the hydrides with a low Ca composition y of less than 0.04. The L(1) term was observed in the hydrides with a Ca composition of more than 0.05, while the L(2) term was observed for more than 0.11. These L(1) and L(2) terms were estimated from a variation with hydrogenation of ellipsometric angle Ψ which is due to optical absorption of CaH(2-α) (L(1)) and MgCaH(3.72) (L(2))., (© 2011 Optical Society of America)