基于MEMS技术集成硅微棱镜耦合和微流道的近红外表面等离子体谐振芯片

为促进表面等离子体谐振（surface plasmon resonance, SPR）测试技术在片上的实现,提出硅基近红外SPR芯片,由硅微棱镜、金属膜和聚合物微流体通道组成．利用有掩膜和无掩膜各向异性湿法腐蚀加工出底角为25．24。的单微硅棱镜阵列,用有掩膜各向异性湿法腐蚀加工出底角为54．74。的双微硅棱镜阵列,利用聚合物的复制注塑技术加工得到微流体通道．在波长1550nm时进行仿真与实验测试,实验测得以空气、水和乙醇为测试介质的SPR角分别为16．75°、22．58°和22．72°,这些值比以玻璃棱镜加工SPR传感器测得的SPR角要小很多．通过实验表明,近红外SPR芯片可以实现表面等离子体谐振传感器微型化,进而推动微全分析系统的实现,降低其成本并提高其性能．     

Characterization of high refractive index semiconductor films by surface plasmon resonance

Si-based surface plasmon resonance (SPR) in the Kretschmann-Raether geometry is considered as a platform for the optical measurement of high refractive index films. The implementation of the SPR effect becomes possible due to the relatively high index of refraction of Si compared to most materials. As examples we study the SPR responses for some important semiconductor-based films, including laser-ablated porous silicon and thin germanium films. Using SPR data, we determine the refractive indices of these films for different parameters (thickness and porosity) and ambiences. We also discuss novel SPR biosensor architectures with the use of these solid films.     

Design of a Novel Substrate-Free Double-Layer-Cantilever FPA Applied for Uncooled Optical-Readable Infrared Imaging System

This paper describes the design and performances of a novel focal-plane array (FPA) containing pixels of double bimaterial-layer cantilevers without silicon (Si) substrate for being applied in the uncooled optical-readable infrared (IR) imaging system. The top layer of the cantilever pixels is made of two materials with large mismatching thermal expansion coefficients: silicon nitride (SiN_x) and gold (Au), which convert IR heat into mechanical deflection. The bottom layer is SiN_x cantilever, which partially serves thermal isolation legs. The top and bottom pads form the resonant cavity, which can dramatically enhance the absorption of incident IR irradiation, and the substrate-free configuration enables reducing the loss of incident IR energy. Responding to the IR source with spectral range from 8 to 14 mum, the IR imaging system may receive an IR images through visible optical readout method. A thermal-mechanical model for such cantilever microstructure is proposed, and the thermal and thermal-mechanical coupling field characteristics of the cantilever microstructure are optimized through numerical analysis method and simulation by using the finite-element method. The thermal-mechanical deflection simulated is 7.2 mum/K, generally in good agreement with what the thermal-mechanical model and numerical analysis forecast. The analysis suggests that the detection resolution of current design is 0.03 K, whereas the noise analysis from FPA indicates the current resolution to be around 100 muK and the limit noise-equivalent temperature difference (NETD) of the IR imaging system can reach to 7 mK.     

Theoretical and experimental study of the surface plasmon resonance effect on a recordable compact disk

The surface plasmon resonance (SPR) effect on noble-metal surfaces has been explored by several investigators for the development of chemical and biological sensors as well as for the design of optical devices for other applications. The effect can be observed by use of prism couplers, diffraction gratings, and specially configured optical fibers. In an attempt to seek a new configuration that minimizes costs of fabricating media that support SPR in conjunction with designing a new format suitable for large-scale chemical and biological sensing, I have investigated the feasibility of using a commercially available, gold-type, recordable compact disk for observation of the SPR phenomenon. Experimental and theoretical results of this investigation are reported.     

基于高斯光束下的Cu2S量子点表面等离激元共振模拟研究

应用COMSOL Multiphysics4．3a模拟软件,结合Maxwell电磁场理论,首先理论推导高斯光束的产生原理,得出基于Kretschmann棱镜耦合系统下的Cu2S量子点溶液,模拟进行852nm稳态激光器的高斯光束照射时产生表面等离激元（SPR）,改变量子点的基本属性以及改变入射光角度,模拟出在不同条件下Cu2S量子点产生SPR信号的情况,为Cu2S量子点在SPR传感方面的应用提供了理论依据和参考。     

Formation of nanosize poly(p-phenylene vinylene) in porous silicon substrate

We report the results of optical investigations in porous silicon (PS)/poly(p-phenylene vinylene) (PPV) systems obtained by filling the pores of silicon wafers with polymer.By scanning electron microscopy (SEM), IR, and Raman spectroscopy, we observed that the porous silicon layer was thoroughly filled by the polymer with no significant change in the structure of the materials. This suggests that there is no interaction between the components. On the other hand, the photoluminescence (PL) spectra of the devices investigated at different temperatures (from 11 to 290 K) showed that both materials are active at low temperatures. Porous silicon has a band located at 398 nm while PPV has two bands at 528 and 570 nm. As the temperature increases, the PL intensity of porous silicon decreases and that PPV is blue shifted. A new band emerging at 473 nm may indicate an energy transfer from the porous silicon to PPV, involving short segments of the polymer. The band of PPV located at 515 nm becomes more dominant and indicates that the nanosize polymer films are formed in the pores of the silicon layer, in agreement with the results obtained by SEM, IR, and Raman analyses.     

硅基光电集成材料及器件的研究进展

以硅基光电集成回路为主线，综述了不同的硅基光波导材料的制备技术和硅基光波导的制作工艺及其对光传输损耗的影响。分析了硅基光波导与锗硅光探测器集成用两种不同的耦合方式，阐明了波导与探测器集成的机理及设计理论基础。归纳出硅基键合激光器的四种技术方案，指出其共同优点是克服材料异质外延引起的晶格失配和热膨胀非共容，对实现OEIC行之有效。     

Refractive-index measurement of bulk materials: prism coupling method

A simple method of measuring refractive indices of bulk materials using a prism coupling procedure is described. Refractive indices are determined from the measurement of the angle incident to the prism at which total reflection on the prism base breaks. This method is shown to possess the advantages of its simple procedure and sample preparation. The accuracy is comparable with that of minimum deviation method if the prism is well calibrated. Experimental results for several materials are given with an evaluation of possible errors.     

Hybrid porous nanotube crystal networks for nanostructured device applications

A set of new porous materials, namely zeolite nanocage schwarzite-like crystals with the elements of both nanotubes and fullerenes in the structure is proposed as a result of ab initio and density-functional theory calculations. Twelve new Extradiamond phases of boron nitride, carbon, silicon and silicon carbide are calculated as three different hybridized crystals. The details of recently synthesized Explosion-BN (E-BN) phase are highlighted for the first time with electronic structure and vibrational frequency analysis. E-BN is supposed to be sp ²/sp ³-hybridized FAU-zeolite structure with calculated unit cell of 12.177 Å and a band gap of 3.2 eV. Calculated IR bands for E-BN₁₂₀ cluster and observed experimentally E-BN absorption spectrum are well-correlated with appropriate IR spectra of FAU-zeolite. Armchair and zig-zag nanotubes are classified as (n,n,k) and (n,0,k), respectively, where k is the number of hexagons along the nanotube axis. Novel materials are proposed as (n,m,k)-FTC, where FTC stands for framework type code. We also indicate the possibility of creation of filled hybrid networks of different segment lengths, radii and compositions for thermoelectric and novel device applications.     

Very thin spin-coated silver films via transparent silver ink for surface plasmon resonance sensor applications

We fabricated very thin silver films with thicknesses of 20 nm, 40 nm, and 60 nm on a prism using a spin coating method for surface plasmon resonance (SPR) image sensor module applications. An aqueous silver ionic complex solution was spin-coated and then thermally cured for 10 minutes at 150 degrees C in an oven. The spin-coated solid silver films possessed silver crystallinity. The prism modules with the 20-nm-, 40-nm- and 60-nm-thick thin silver films were applied to an SPR image sensor system. The coefficients of determination for the 20-nm-, 40-nm- and 60-nm-thick silver films were 0.923, 0.990 and 0.989, respectively when standard ethanol solutions with 0.1% intervals in the range of 20.0% to 20.5% were applied. The correlation is high-performed and the coefficients of determination are as close as 1. The spin coating method of very thin silver films for SPR image sensor modules is expected to be a very cost-effective solution because the films can be formed at a low temperature in a short period of time without requiring a vacuum system.     

Effect of nonparallelism of guiding air-liquid layers on the reflection dip in attenuated total reflection

The effect attributable to the nonparallelism of the guiding layer of a planar waveguide on the reflection dip of the attenuated total reflection (ATR) spectrum is investigated. It is considered that the reflected light from a nonparallel waveguide is, indeed, the superposition of a series of beams propagating in different directions. The ATR spectra are numerically calculated with various inclination values. Compared with those of the corresponding parallel ones, with the inclination of waveguides exceeding 1 microrad, the characteristics of the ATR spectra begin to differ considerably, and when the inclination reaches 10 microrad, the sensitivity of sensors based on the waveguide is reduced by 62.7% and 67.3% for the free space coupling structure and the prism coupling structure, respectively. When the inclination becomes larger than 100 microrad, the ATR phenomenon cannot be observed any longer.     

All-optical bistability in doped-polymer film waveguides

All-optical bistability was observed in thin-film waveguides made with acceptor-donor substituted azobenzene-doped poly(methyl methacrylate) polymer. Input-output curves with hysteresis characteristics were measured. The origin of the bistability was attributed to nonlinear coupling between a prism and a doped-polymer waveguide. An approximately theoretical analysis was introduced. Theoretical predictions were qualitatively consistent with experimental results.     

硅改性环氧树脂复合材料的研究进展

综述了纳米二氧化硅和有机硅等硅质材料改性环氧树脂复合材料的性能特征,论述了硅质材料的类型、用量和改性方法对复合材料力学性能、电性能、耐蚀性、热稳定性和阻燃性等的影响。讨论了表面化学修饰纳米二氧化硅和有机硅与环氧树脂的共聚方法以及材料微观结构对复合材料性能的影响和机理。硅质材料的分散性和含量是影响复合材料性能和微观结构的主要因素,对纳米二氧化硅进行表面化学修饰或改进共聚、共混是改善硅分散性以及复合材料微观结构和性能的有效途径。     

Modelling and characterisation of surface plasmon based sensors for the detection of E. coli

The finite element method based on the full-vectorial H-field formulation incorporating the perturbation techniques has been employed to calculate the complex propagation characteristics, the formation of the coupled supermodes, and power fraction in the different regions, modal loss, differential loss and coupling length. The influence of the outer medium refractive index on the inner and outer surface plasmon modes (SPR) is investigated to achieve the best coupling and sensitivity. Finally the SRP fibre optic sensor design is numerically optimised for the maximum field penetration in the outer medium     

粘接剂对自冲铆-粘接复合接头强度的影响及数理统计分析

以自冲铆接和自冲铆-粘接复合接头为对象,采用数理统计分析检验实验数据合理性,进而对比不同材料组合及连接方式来分析粘接剂对自冲铆接接头强度的影响。实验表明,自冲铆接的剪切强度比剥离强度高;粘接剂对异种材料组合(硬质材料置于上板)自冲铆接的影响较同种材料组合自冲铆接更显著;异种材料组合(硬质材料置于上板)自冲铆-粘接复合技术,采用胶层厚度为0.1mm时,可获得有效的连接结构且具有良好的承载能力;T型异种材料组合压印连接吸震、缓冲效果更好。     

Effect of resonant localized plasmon coupling on the sensitivity enhancement of nanowire-based surface plasmon resonance biosensors

A nanowire-based surface plasmon resonance (SPR) is investigated as a structure that offers improved sensor performance. The results calculated by rigorous coupled-wave analysis on a model using a hexanedithiol self-assembled monolayer (SAM) indicate that the resonant coupling between localized surface plasmons (LSPs) of nanowires affects the sensitivity enhancement substantially, while the LSP resonance in a single nanowire also contributes. SPR characteristics change significantly by applying a SAM, which can give rise to zero sensitivity for a given SAM. The results suggest that a properly designed nanowire-based SPR biosensor can enhance sensitivity by an order of magnitude with reasonable detection properties.     

Cytotoxic evaluation of silicon nitride-based ceramics

Silicon nitride-based ceramics are potential candidates as materials for orthopedic implants due to their chemical stability associated with suitable fracture toughness and propitious tribologic characteristics. Therefore, in this work, dense silicon nitride components are investigated considering their suitability as biomaterials. Initially, two different compositions of silicon nitride were considered, using ytterbium, yttrium and aluminum oxides as sintering aids. The materials were sintered in a carbon resistance furnace under nitrogen atmosphere and were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) in order to characterize the microstructure. Indentation method was applied in order to obtain hardness and fracture toughness measurements, and in vitro test of cytotoxicity was performed for a preliminary biological evaluation. A microstructure composed of grains of beta-silicon nitride distributed in a secondary phase was observed. The samples achieved fracture toughness values of 5 MPa m^1/2 and Vickers hardness values of 13 GPa. Since a nontoxic behavior has been observed during the cytotoxicity tests with the samples, this finding suggests that silicon nitride-based ceramic can be used as a material for clinical applications.     

Application of an absorption-based surface plasmon resonance principle to the development of SPR ammonium ion and enzyme sensors

Two new types of surface plasmon resonance (SPR) sensors that can determine the concentration of ammonium cations and urea were realized based on the previously reported theory of the absorption-based SPR measurement method. The change of the dielectric constant caused by the change of the light absorption characteristics of dyes incorporated in a sensing membrane phase is utilized in these SPR sensors. The determination of ions using the SPR sensor was realized by detecting the SPR signals of the minimum reflectance related to the change of absorption spectra of the dye in the ion optode membrane consisting of an ammonium-selective ionophore (TD19C6) and a lipophilic cationic dye (KD-M11) that shows absorption spectral changes due to protonation and deprotonation. A SPR enzyme sensor that can determine the concentration of urea was prepared by the combination of this ion optode membrane and an enzyme membrane based on urease. With the newly developed SPR sensors, the intensity changes of the reflectance at the fixed SPR resonance angle are monitored, which is different from conventional SPR sensors where usually the change of the SPR resonance angles is detected. In a continuous-flow experiment using the SPR ion sensor for NH4+ ion determination, a dynamic measurement range from 10(-5) to 10(-2) M was achieved. In the case of the enzyme-based SPR urea sensor, a dynamic range from 10(-4) to 10(-1) M was observed in a stopped-flow batch arrangement. It is expected that this sensing technique can be applied for the SPR-based detection of a wide range of low molecular weight analytes.     

Strong coupling between nanoscale metamaterials and phonons

We use split ring resonators (SRRs) at optical frequencies to study strong coupling between planar metamaterials and phonon vibrations in nanometer-scale dielectric layers. A series of SRR metamaterials were fabricated on a semiconductor wafer with a thin intervening SiO(2) dielectric layer. The dimensions of the SRRs were varied to tune the fundamental metamaterial resonance across the infrared (IR) active phonon band of SiO(2) at 130 meV (31 THz). Strong anticrossing of these resonances was observed, indicative of strong coupling between metamaterial and phonon excitations. This coupling is very general and can occur with any electrically polarizable resonance including phonon vibrations in other thin film materials and semiconductor band-to-band transitions in the near to far IR. These effects may be exploited to reduce loss and to create unique spectral features that are not possible with metamaterials alone.     

Modeling of evanescent coupling between two parallel optical nanowires

Evanescent coupling between two parallel nanowires is investigated using the finite-difference time-domain method. Silica, tellurite, and silicon nanowires are used as typical materials in the simulation. Compared with weakly coupled waveguides, strongly coupled nanowires show much smaller transfer lengths without sacrificing high coupling efficiencies, suggesting possibilities for developing highly compact evanescent-coupling-based nanowire photonic devices, as well as for achieving high-efficiency interconnection between nanowires and external optical systems. Meanwhile, the polarization-dependent coupling properties, the considerably high minimum coupling efficiency, and the supermode-cutoff-like behavior are also observed. Evanescent coupling properties of strongly coupled nanowires demonstrated may provide valuable references for practical applications of optical nanowires.