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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.

Spectral selective radiating material (SSRM) such as a SiO film deposited on metallic substrate can be cooled lower than the ambient temperature due to its high IR emission in the spectral region of the atmospheric window under clear sky conditions. In this paper we propose a new stacked SSRM consisting of SiO film and [V.sub.1-x][W.sub.x][O.sub.2] thermochromic film to stabilize the surface temperature of the sky radiator. The transition temperature from metallic to semiconductor phase of [V.sub.1-x][W.sub.x][O.sub.2] thermochromic film can be adjusted to a temperature near ambient by the control of the doping level of x. The radiative cooling of the new SSRM was simulated using the optical constants of SiO and [V.sub.1-x][W.sub.x][O.sub.2] obtained by optical measurements. The results reveal that the newly designed SSRM can attain a stable surface temperature determined by the transition temperature of the [V.sub.1-x][W.sub.x][O.sub.2] film.

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.

The experimental studies of thermal tuning of the localized surface plasmon resonance (LSPR) of Ag nanoparticles on a thermochromic thin film of V[O.sub.2] is reported. The tunable wavelength range has depended on the particle size or the mass thickness of the metal nanoparticle film and the tunability is enhanced by introducing a layer of Ti[O.sub.2] to overcoat the Ag nanoparticles.

The use of localized surface plasmon resonance (LSPR) of Ag nanoparticles to tailor the optical properties of V[O.sub.2] thin film is reported. The V[O.sub.2] film is influenced by LSPR and has exhibited an anomalous thermochromic behavior in the modification wavelength region that might find use in optical switching applications.