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Fano resonance (FR) has attracted more attention recently due to its outstanding properties, such as coherent interference at the resonant energy and intense changes in the spectral lines. Here, we studied the FR effects in the CsPbBr3 nanocrystal (NC)/Ag nanostructure coupling structure. The FR effects cause asymmetric line shapes in both the reflection and transmission spectra. A sharp variation was observed in the spectral line at the exciton energy of CsPbBr3 NC. The FR in this coupling structure is attributed to the configuration interaction between the exciton state and the surface plasmon (SP) states. From the coupling theory, we suggest that it is necessary to consider multiSP states in the interaction Hamiltonian, instead of a single SP state, which will induce more interesting effects. Moreover, we demonstrate that the FR effects are sensitively dependent on the spacing in the coupling structure. The sharp variation of the spectral line shape at the resonant energy and its sensitivity on the spacing in the coupling structure make the FR effects an important candidate as the optical monitoring methods in the application of real time artificial tunable optoelectronic device at the nanoscale. [ABSTRACT FROM AUTHOR]

Phonon modes of PbTe films grown by molecular beam epitaxy have been studied by micro-Raman scattering. On the as-grown PbTe surface, strong TeO2 phonon vibrational modes were detected, which obscured the observation of the longitudinal optical (LO) phonons of PbTe in early conventional Raman scattering experiments. Existence of a TeO2 layer on the PbTe surface is confirmed by observation with x-ray photoemission spectroscopy. After removal of TeO2 by chemical etching, the LO phonons for PbTe films were unambiguously observed. Misfit strain accommodated in the epitaxial films makes the lattice distorted from cubic structure, which lowers the crystal symmetry and leads to observation of what would normally be Raman inactive LO phonon modes for PbTe. [ABSTRACT FROM AUTHOR]

Power converters consisting of naturally commutated thyristors such as cycloconverters and current source inverters were the first to be used in driving electrical motors with variable speed, but now, due to their inferior performance compared to forced commutated converters, their use is restricted in the high voltage/high power range where the performance and cost of forced commutated switching devices are not yet competitive. Hybrid cycloconverters proposed recently are capable of improving the performance of cycloconverters by adding an auxiliary forced commutated inverter with reduced installed power. It will be shown that the new topology is not only able to improve the quality of the output voltage but is also able to enhance the control over the circulating current and, therefore, for some of the cycloconverter arrangements, to improve the input power quality. This paper evaluates the performance of a few standard and hybrid cycloconverter arrangements using both simulation and experimental results. [ABSTRACT FROM AUTHOR]

Abstract: Cubic Mg x Zn1−x O thin films were deposited on amorphous silicon dioxide substrate by reactive electron beam evaporation (REBE) at low temperature (250°C). The characterizations of crystalline structure and morphology of the ternary films demonstrated that the cubic Mg x Zn1−x O films are of highly (001) orientation and have uniform surface. The cubic Mg0.83Zn0.17O film deposited on quartz demonstrates wide band gap (6.45eV) and has very high transparency (>95%) in broad wavelength range from ultraviolet (0.3μm) to mid-infrared light (5.5μm). The refractive indices for the cubic Mg x Zn1−x O decrease as Mg fraction increases. The characters of low optical absorption in broad wavelength range and feasibility of changing refractive index by Mg fraction variation in the ternary Mg x Zn1−x O films could render potential applications in integrated optical devices. [Copyright &y& Elsevier]

Dendritic Ag2Se nanostructures are synthesized in a dry environment by UV irradiating the hybrids composed of CdSe quantum dots (QDs) and silver (Ag). UV irradiation on CdSe QDs induces a photooxidation effect on the QD surface and leads to the formation of SeO2 components. Then SeO2 reacts with the Ag atoms in either Ag film or QD layer to produce the Ag2Se. The growth mechanism of Ag2Se dendrites on solid Ag films is explored and explained by a diffusion limited aggregation model in which the QD layer provides enough freedom for Ag2Se motion. Since the oxidation of the CdSe QDs is the critical step for the Ag2Se dendrites formation this dry chemical interaction between QDs and Ag film can be applied in the study of the QD surface chemical properties. With this dry synthesis method, the Ag2Se dendrites can also be facilely formed at the designed area on Ag substrates.

A reflective fiber temperature sensor system based on the ZnO thin film is proposed. The transmittance spectra and temperature dependent optical property of the sensing head with ZnO thin film is investigated theoretically and experimentally, and the temperature resolution of ∼1 °C is obtained in the temperature region of 300-773 K. The temperature sensing system is only related to the wavelength shift of transmittance spectra, and has a high stability without depending on the incident light intensity. This research results also indicate a fiber optical sensor with a broad temperature measurement range (10-1800 K) can be gained as a promising temperature sensing device, and can be applied into some extremely environments, such as aircraft, nuclear power station and power transmission system, and so on.