We present large-area ultrathin metasurfaces that transmit visible light and reflect near-infrared (NIR) wavelengths. These visible-transparent metasurfaces consist of 10 nm-thick monolayer of randomly dispersed silver nanodisks, that is only λ/90 thickness at the reflection peak wavelength. Calculated optical properties of the structure show that the reflectance for NIR wavelengths increases monotonically as a function of increasing nanodisk density, while the absorption saturates and scattering of visible light decreases. We demonstrate that the proposed structure is easy to fabricate with chemically synthesized silver particles using the bottom-up method and has industrially applications.
Self-ballasted compact fluorescent lamps (CFLs) have been developed and improved in these twenty years. In Japan, the CFLS that have diffusive glass globes to replace incandescent lamps have been developed, but their sizes were too large to fit in the luminares of incandescent bulbs. Thus, we have developed the self-ballasted CFL of an "A60" bulb shape, which has the maximum diameter of c60 mm and the length of 123 mm. This lamp could be substituted for a 60 W incandescent lamp. In order to realize this lamp size, we opt.imized the discharge tube diameter, filling gas type and pressvre, the shape and makmg process of the dlscharge tube After all the tnple "U" connected tube Is selected, which has a decisive advantage against a multi-folded tube on the luminous maintenance during life, but also has a disadvantage on the luminous run-up characteristics. We investigated the behaviors of mercury, especially the mercury diffusion phenomenon released from the auxiliary amalgam-Wags after ignition by both experiments and calculation. The luminous run-up characteristic has been much improved.
Abstract:We present ultrathin multilayer metamaterial absorbers based on abundant, low-cost materials, to effectively harness solar energy for heating and evaporation of water. We report on the design and experimental demonstration of ultrathin, broadband meta-surface absorbers for solar energy harvesting and conversion to heat in water for applications such as desalination, distillation, sterilization and purification. Structures are engineered to absorb >90% of incident light across a broad wavelength range from 300 to 1540 nm, and to concentrate this energy in the top 100 nm of the absorber where it can be efficiently transferred to water and thereby harnessed to accelerate evaporation.There is great and still growing interest in green energy sources that can reduce the collective energy footprint on the environment in the face of accelerating consumption. Solar energy harvesting is well known in the context of photovoltaic technologies but it may also be converted to heat and readily applied to the heating and evaporation of water for desalination, distillation, sterilization and purification, in particular where conventional power sources are unavailable. Such applications require not only an absorber covering as much as possible of the broad UV-NIR solar spectrum but one in which heat is generated and concentrated in a thin surface layer for efficient transfer to surrounding water. 'Perfect' metamaterial absorbers comprising metal/dielectric/nanostructured-metal tri-layers have become a familiar concept in recent years as the basis of resonant and wide-angle absorbers. These are typically based on noble metals, specifically gold and silver, for their strong, low-loss plasmonic properties in the VIS-NIR range but these are expensive metals and not well-suited to high absorption across the full UV-NIR solar spectrum. Here we present broadband meta-surface absorbers based on a low-cost, lossy metal (chromium) as opposed to the noble metals. Through a series of fully three-dimensional finite-element Maxwell solver simulations we evolved a five-layer absorber structure based on chromium (Cr), aluminum (Al) and silica (SiO 2 ) as shown in Fig.
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