ABSTRACT
In this paper, the glass systems, TeO2-ZnO-BaO (TZB), TeO2-ZnO-BaO-Nb2O5 (TZB-Nb) and TeO2-ZnO-BaO-MoO3 (TZB-Mo), were fabricated by the traditional melt-quench protocol for use as mid-infrared (mid-IR) transmitting optical material. The effect of Nb2O5 and MoO3 on the key glass material properties was studied through various techniques. From the Raman analysis, it was found that the structural modification was clear with the addition of both Nb2O5 and MoO3 in the TZB system. The transmittance of studied glasses was measured and found that the optical window covered a region from 0.4 to 6 µm. The larger linear refractive index was obtained for the Nb2O5-doped TZB glass system than that of other studied systems. High glass transition temperature, low thermo-mechanical coefficient and high Knoop hardness were noticed in the Nb2O5-doped TZB glass system due to the increase in cross-linking density and rigidity in the tellurite network. The results suggest that the Nb2O5-doped TZB optical glasses could be a promising material for mid-infrared transmitting optics.
ABSTRACT
The surface plasmon resonance (SPR) properties of Au/Ag bimetallic thin-film nanostructures were investigated to improve the chemical stability and the figure of merit (FOM) in the SPR sensors. The SPR characteristics such as resonance angle, extinction ratio, and full width half maximum (FWHM) were calculated by the simulation of the finite-difference time-domain method and were measured using the laser with a 632.8 nm wavelength in the Kretschmann-Raether configuration. The measured resonance angle, extinction ratio, FWHM of Au(20 nm)/Ag(20 nm) thin-film nanostructure were found to be 44°, 0.8, and 1.4°, respectively. The FOM values were determined to be 56.9 for Au/Ag bimetallic thin-film, 47.9 for Au(50 nm) single thin-film, and 89.1 for Ag(50 nm) single thin-film. Also the sensitivity values were about 53.5, 57.0, and 57.8°/RIU for Au(50 nm), Ag(50 nm), and Au(20 nm)/Ag(20 nm) thin-film nanostructures in the SPR sensors, respectively. The SPR properties of Au/Ag bimetallic thin-film nanostructures were compared with those of the Au and Ag single thin-film nanostructures.
ABSTRACT
A double layered plasmonic device based on transferring technique with polystyrene nano-beads is analyzed and demonstrated to increase the sensing characteristics of plasmonic sensor system. The double layered plasmonic devices are calculated using the three-dimensional finite-difference time-domain method for the width and thickness of the nano-hole structures. The double layered plasmonic devices with different diameters of the Au nano-hole are fabricated by transferring method with commercially available chloromethyl latex with a diameter of 0.42 µm. The optimum sensing characteristic of the proposed plasmonic device is obtained with the film and the hole thickness of 15 and 15 nm in the 246 nm wide nano-hole size. The best sensitivity of the proposed plasmonic sensor is 67.7 degree/RIU when the sensitivity of the conventional plasmonic sensor is 42.2 degree/RIU.
ABSTRACT
Up-conversion phosphors have attracted considerable attention because of their applications in solid-state lasers, optical communications, flat-panel displays, photovoltaic cells, and biological labels. Among them, NaYF4 is reported as one of the most efficient hosts for infrared to visible photon up-conversion of Yb3+ and Er3+ ions. However, a low-temperature method is required for industrial scale fabrication of photonic and optoelectronic devices on flexible organic substrates. In this study, hexagonal ß-NaYF4: 3 mol% Yb3+, 3 mol% Er3+ up-conversion phosphor using Ca2+ was prepared by chemical solution method. Then, we synthesized a nanostructured organo-silicon compound from methyl tri-methoxysilane and 3-glycidoxy-propyl-trimethoxy-silane. The transmittance of the organo-silicon compound was found to be over 90% in the wavelength range of 400~1500 nm. Then we prepared a fluoride-based phosphor paste by mixing the organo-silicon compound with Na(Ca)YF4:Yb3+, Er3+. Subsequently, this paste was coated on polyethylene terephthalate, followed by heat-treatment at 120 °C. The visible emission of the infrared detection card was found to be at 655 nm and 661 nm an excitation wavelength of 980 nm.
ABSTRACT
Novel triangular ring resonators combining extremely small multimode-interference (MMI) coupler, low loss total internal reflection (TIR) mirrors, and semiconductor optical amplifiers are reported for the first time. The MMI length of 90 microm is among the shortest reported. The incidence angle of the TIR mirror inside the resonator is 22 degrees. A free-spectral range of approximately 2 nm is observed near 1550 nm along with an on-off ratio of 17 dB. The triangular resonators with a sharp angle are very attractive components due to their promise of compact size and high levels of integration. Therefore, large numbers of resonators can be integrated on a chip to increase functionality in future optical wavelength division multiplexing system.
