High-performance thermochromic VO2-based coatings with a low transition temperature deposited on glass by a scalable technique.

We report on high-performance thermochromic ZrO2/V0.982W0.018O2/ZrO2 coatings with a low transition temperature prepared on glass by a low-temperature scalable deposition technique. The V0.982W0.018O2 layers were deposited by a controlled high-power impulse magnetron sputtering of V target, combined with a simultaneous pulsed DC magnetron sputtering of W target to reduce the transition temperature to 20-21 °C, at a low substrate surface temperature of 330 °C in an argon-oxygen gas mixture. ZrO2 antireflection layers both below and above the thermochromic V0.982W0.018O2 layers were deposited at a low substrate temperature (< 100 °C). A coating design utilizing a second-order interference in the ZrO2 layers was applied to increase both the luminous transmittance (Tlum) and the modulation of the solar transmittance (ΔTsol). The ZrO2/V0.982W0.018O2/ZrO2 coatings exhibit Tlum up to 60% at ΔTsol close to 6% for a V0.982W0.018O2 thickness of 45 nm, and Tlum up to 50% at ΔTsol above 10% for a V0.982W0.018O2 thickness of 69 nm.

Shape Dependent EMA Model of Nanostructured Anisotropic Materials.

Heterogeneous nanostructures containing nanoparticles of various sizes and shapes have attracted significant attention in the development of nano-biosensors. Especially, plasmonic properties of such materials are advantageously exploited for the detection of biological and chemical substances. Since these media exhibit optical anisotropy, a valid homogenization procedure must be able to describe appropriately the relationship between the geometry of the inclusions and the nature of local field modes. We present a model approach for extension of the effective medium approximation (EMA) and its application to anisotropic nanostructures. The proposed model is based on a "strong-couple-dipole" (SCD) method including a volume-integral correction term in a Green tensor that enables to obtain more accurate representation of polarizability tensor. Derived depolarization factors for discs and bi-cone particles are compared with the early known shapes (spheroids, cylinders) and applied to nanostructures composed of the Fe or Au nanodots in polyacrylate.

Design of Plasmonic-Waveguiding Structures for Sensor Applications.

Surface plasmon resonance has become a widely accepted optical technique for studying biological and chemical interactions. Among others, detecting small changes in analyte concentration in complex solutions remains challenging, e.g., because of the need of distinguishing the interaction of interest from other effects. In our model study, the resolution ability of plasmonic sensing element was enhanced by two ways. Besides an implementation of metal-insulator-metal (MIM) plasmonic nanostructure, we suggest concatenation with waveguiding substructure to achieve mutual coupling of surface plasmon polariton (SPP) with an optical waveguiding mode. The dependence of coupling conditions on the multilayer parameters was analyzed to obtain optimal field intensity enhancement.

Monitoring radionuclides in the atmosphere over the Czech Republic after the Fukushima Nuclear Power Plant accident.

This paper presents the results of atmospheric radioactivity monitoring over the Czech Republic, as obtained by the Radiation Monitoring Network, following the Fukushima Dai-Ichi Nuclear Power Plant accident. Maximum values for (131)I were 5.6 mBq m(-3) in aerosol form and 13 mBq m(-3) in gaseous form. The maximum values for (134)Cs and (137)Cs were 0.64 and 0.72 mBq m(-3), respectively. The estimated effective half-time for removing the activity from the atmosphere was 6-7 d and 3.5 d for caesium and iodine, respectively. The gaseous-to-total activity ratios of (131)I ranged between 0.3 and 0.9, with an arithmetic mean value of 0.77. The mean value for the (134)Cs/(137)Cs ratios was close to 1.0. The effective inhalation dose due to the accident for an adult living in the Czech Republic was estimated at <4 × 10(-5) mSv, out of which the proportion of (131)I was 88%.

Numerical study on the spectroscopic ellipsometry of lamellar gratings made of lossless dielectric materials.

The spectroscopic ellipsometry of lamellar gratings made of lossless dielectric materials is studied numerically by using the rigorous coupled-wave method with the use of Li's Fourier factorization rules [J. Opt. Soc. Am. A 13, 1870 (1996)], which are known to improve the convergence on the analyses of metallic gratings. Numerical results show that the calculation method also provides fast convergence on lossless gratings, and accurate values of the ellipsometric angles are obtained in very short computation times. Moreover, estimation of grating parameters is investigated by using a cost function defined by the average distance on the Poincaré sphere, and it is shown that the computation required for accurate estimation is possible in reasonable computation time.