Advanced Materials in Microwaves and Optics

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作者: Shu Hui Li, Xiao Jun Li
摘要: The Verdet constant is the essential parameter of Faraday Effect. Study on Verdet constant of magnetic optical medium is very important in Faraday Effect research and application. In this paper, Verdet constant of liquid and solid medium were investigated with light extinction method with the help of photoelectric detector. Using the square wave magneto-optic modulation method which we established, Verdet constant of air was measured. Variation of Verdet constant of these materials with changes of light wavelength and temperature was investigated. These experimental data may provide reference for research and application of magneto-optic effect. Meanwhile, the experiment in this paper is also one of the key works of magnetic rotation imaging method for geomagnetic field measurement which we proposed. It will provide experimental support for this new geomagnetic field measurement method.
作者: Si Wei Huang, Ang Zhang, Xiao Lin Tian, Yan Kui Sun
摘要: An edge detection algorithm which is applied to anterior chamber OCT images has been proposed. The algorithm firstly uses multi-structure elements to detect edge on gray level value differences on the same scale, and introduces dynamic adaptive weight to make re-fusion of pixels to gain a multi-structure element morphological edge detection image on the same scale, then confirms weight value and makes multi-scale fusion according to the noise immunity of different scale structure elements to gain the final edge detection image. The simulated results have obvious edge features,it can effectively avoid the occurrence of mutational pixels on the OCT image edge results, compared to traditional edge detection algorithms.
作者: Hikari Dezaki, Tadao Tanabe, Hai Yan Jin, Yutaka Oyama
摘要: 1.2μm – laser pumped wide frequency tunable coherent terahertz (THz) light source is demonstrated. The operation principle is based on difference frequency generation (DFG) with an excitation of phonon – polariton in Gallium Selenide (GaSe) crystal. The pump and signal lasers used are 1.2μm Cr:Forsterite lasers. The tuning range of the THz wave frequency covers from 0.3THz to 4.8THz (type eoo phase matching) and 8.3THz to 10.2THz (type eoo phase matching) under collinear phase matching conditions. It is shown that the maximum conversion efficiency is up to ~10-6, which is 3 orders in magnitude larger than that of Gallium Phosphide (GaP) crystal.
作者: Yee Sin Ang, Chao Zhang
摘要: We demonstrate that bilayer graphene exhibits strong nonlinear optical response in the terahertz frequency regime. The electric field strength required to generate single-frequency and triple-frequency nonlinear optical responses comparable to the linear optical response is only moderate and can be easily achieved in laboratory. This strong nonlinear optical response persists even in room temperature. This suggests that bilayer graphene can potentially be utilized in nonlinear terahertz photonics.
作者: Hikari Dezaki, Meng Long Jing, Sundararajan Balasekaran, Tadao Tanabe, Yutaka Oyama
摘要: An efficient continuous wave (CW) THz source working at nominal room temperature is described. Optically pumped room temperature THz emission is observed from various kinds of semiconductor bulk crystals. In order to investigate the emission mechanism, temperature dependences of terahertz emission intensity in various semiconductors are measured. Semiconductor samples used are InSb, InSb:Ge, InAs, GaSb, Ge, and Si. From these results, it is shown that the temperature dependences of emission characteristics are different between direct and indirect transition semiconductors, and that the high resistive Ge is suitable for room temperature THz emitter via intracenter transitions excited by IR pump lasers.
作者: Yuan Yuan Dai, Jian Yuan, Jing Ren Zhang, Lian Wang Wang
摘要: As filter media sand, ceramic has the certain removal effect in treating turbidity, organic matter from water .but the removal rate is limited. Modied filter could change filter surface characteristics. in this article, modied ceramic with aluminum hydroxide 。the experimental resulta showe that the trentment effect of ceramics filter coated aluminum is higher than ordinary ceramic in turbidity, CODMn, UV254 in the water, the removal efficacy is 96.64%,38.14%,47.77%respectively,aftercoated aluminum ceramic getting through the filter candle ,the Zeta potential of filter water is more close to zeto point and helpful for adhering to particles and intercepted. Conventional filtering process of water plant adopting quard sand ,ceramic so on media has low treatment tate in low turbidy , contaninging organic micro-polluted source watet .the reason that those media specific surface area is limited ,under neutral condition surface carries negative charge,absorption capacity is little.which affect impurities adhesion on filter materials[1],to make outlet water quality improved ,.people begin to seek economic,good treatment effect filter media,modified media has become a kind of new workmamship in rencent 10 years[2-6]. .Modified media could make ordinary media surface properties improve, enhance intercepting capability and much study regard sand as carrier .and ferric chloride,ferric nitrate,aluminum oxide as modifier. adopt study of modified ceramic little,although ceramic has more porosity , aperture and specific sueface area,which formed internal surface area is smaller respectively .accoding to sanitary standard for drinking water ,ameliorating ceramic performance and advancing effluent is urgently to be solve daboutsubject. this study used aluminum hydroxide as modifier ,investigated coater aluminum ceramic filtering effect.
作者: Yong Qin, Zhen Zhou, Jing Hou, Li Jie Wang
摘要: The detection of milk proteins can be achieved by light scattering. But in the process of detection, there are many influences that directly affected the accuracy of detection. On the basis of researching the light scattering characteristic of milk proteins, we have studied the effect of physical-chemical conditions such as scattering angle and temperature on scattering light intensity. Through simulation experiments, we can find that parameters such as scattering angle and temperature also have directly impact to the casein micelle detection. According to the simulation result, the detection parameter has been optimized, the theoretical support and guidance for increase the detection accuracy also has been provided.
作者: Ren Zhe Wang
摘要: The sensing technology based on sensitive conductive composites was used on the reinforced cushion in a coal mine silo foundation. The reinforced belt sensor made from sensitive conductive rubber’s composites was flexible and large deformation. It is the ideal test sensor for the low-modulus and large strain reinforce belt. The results show that the new type of sensor performance is stability and the test is good.
作者: Sudhir Chandra, Atul Vir Singh
摘要: In present work, we report preparation and characterization of piezoelectric films of zinc oxide (ZnO) and aluminum nitride (AlN) by RF magnetron sputtering using respective ceramic targets. The effect of ambient gas, substrate temperature, RF power and sputtering pressure has been studied to get highly c-axis oriented films for potential applications in micro-electromechanical systems. The films were characterized by X-ray diffraction technique to identify the crystallographic orientation. It was observed that the film deposited in pure Argon (Ar) ambient were amorphous or weekly crystallized with no preferred (002) orientation. On the other hand, the films prepared in Ar-O2 for ZnO were highly c-axis oriented. Similarly AlN films were observed to be oriented along c-axis perpendicular to substrate only when deposited in mixture of Ar-N2. To demonstrate the application of piezoelectric properties, an FBAR device (Film Bulk Acoustic Resonator) using ZnO thin film was fabricated. ZnO films are very sensitive to the chemicals used in the micro-electro-mechanical systems (MEMS) fabrication processes which include acids, bases and etchants of different material layers (e.g. SiO2, chromium, gold etc.). A specially designed mechanical jig was used for physically protecting the film during Si anisotropic etching process in potassium hydroxide solution. The potential applications of these films in various RF MEMS devices have been discussed.
作者: Javlon D. Elchiev, Muzaffar M. Djalalov, Aleksandr A. Simonov
摘要: There has shown new vacuum technique of making planar waveguides doped with rare earths, on the basis of simultaneous vacuum deposition of quartz and alloying components. This technology allows to create optical waveguiding layers and amplifying planar compositions on wafers of silicon or quartz, and allows the dose-doping quartz with rare-earth elements, as well as germanium oxide and aluminum oxide, to obtain the optimal composition of a planar waveguide. With the help of lithography formed planar guide mediums with amplifying and modulating properties. There have been researched the methods of production of laboratory models of optical amplifying mediums, using vacuum technology, for the manufacture of planar erbium-doped amplifiers.