This PDF file contains the front matter associated with SPIE Proceedings Volume 7039, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

Recently developed metal nanoshells are ideal building blocks for metal-dielectric photonic crystals operating in visible and near-infrared spectrum. We applied silica coating to screen the van der Waals force and also added a dispersant to increase the electrostatic repulsive force. We also stabilized the gold nanoshell sterically by using a surfactant. With the use of tetrasodium pyrophosphate as a dispersant and Tween as a surfactant, we successfully obtained highly stable colloidal solution of gold nanoshells and subsequently self-assembled them into highly ordered opal structures. We observed well-defined diffraction pattern in the fast Fourier Transform spectra and optical spectra that match well the theoretical photonic band structure.

Previous studies on dewetting of ultrathin Co films by nanosecond pulsed laser melting have shown that the films dewet due to a thin film hydrodynamic instability and form a system of ordered nanoparticles with uniform average size and nearest neighbor particle spacing. For Co films less than 8 nm thick, the nanoparticle spacing, λ_NN was dependent on the initial film thickness, h, and varied as h². For Co films thicker than 8 nm, the nanoparticle spacing decreased with increasing film thickness, due to a thermocapillary effect generated by the ns laser heating. Here we show the results from investigations on dewetting of Co films that had initially much rougher surfaces with root mean square roughness values, 0.9 < R_rms < 2.8 nm as compared to smoother films examined in prior investigations, for which R_rms ≤ 0.2 nm. Laser induced dewetting of Co films with much large R_rms values generated nanoparticles that were qualitatively similar to those created from smoother Co films. The size distribution of the nanoparticles was monodispersed and there was short range spatial order present in the system from the average nearest neighbor nanoparticle spacing; however, a drastic reduction in the characteristic length scales was observed in the nanoparticulate arrays created from the rougher Co films. This result suggests that knowledge of film thickness and roughness are important towards predicting characteristic length scales from metal film dewetting.

Carbon fiber reinforced polymer (CFRP) has been recently applied to not only wing, but also fan blades of turbo fan engines. To prevent impact force, leading edge of titanium was often mounted on the CFRP fan blades with adhesive force. In order to enhance the joining strength, a joining method with carbon fiber reinforced interface has been developed. By using nickel-coated carbon fibers, a joining sample with carbon fiber-reinforced interface between CFRP and CFRM has been successfully developed. The joining sample with nickel-coated carbon fiber interface exhibits the high tensile strength, which was about 10 times higher than that with conventional adhesion. On the other hand, Al-welding methods to steel, Cu and Ti with carbon fiber reinforced interface have been successfully developed to lighten the parts of machines of racing car and airplane. Carbon fibers in felt are covered with metals to protect the interfacial reaction. The first step of the welding method is that the Al coated felt is contacted and wrapped with molten aluminum solidified under gravity pressure, whereas the second step is that the felt with double layer of Ni and Al is contacted and wrapped with molten steel (Cu or Ti) solidified under gravity pressure. Tensile strength of Al-Fe (Cu or Ti) welded sample with carbon fiber reinforced interface is higher than those of Al-Fe (Cu or Ti) welded sample.

Laser-induced melting of ultrathin films can lead to self-organized arrays of hemispherical particles. We have applied this procedure to assemble arrays of Fe nanomagnets on SiO₂ substrates. Morphological studies showed presence of spatial short range order (SRO) in the array. Magnetic properties were studied at room temperature using zero-field magnetic force microscopy (MFM). The particles upto 55 nm in diameter showed in-plane (≤ 45°), compared to out-of-plane magnetization directions (≥ 45°) for the larger particles. The size-dependent orientation of magnetization for these hemispherical particles, was attributed to the dominating magnetostrictive energy and a size-dependent residual strain.

The Cost of ownership (COO) due to the mold can be minimized by first creating the smallest possible original. The cost of this original can be reduced by using the lowest possible resolution pattern generator. If the pattern is regular, then analog pattern generation such as interferometry can be used. The small original is then copied to cover the area by either Step and Repeat or Tiling. Finally multiple working copies are made in a tooling tree for production imprint. The cost and life of the working copies depends on the imprint technology.

We report a large-area, dual-scale metal transfer method by using a difference in adhesive force. Rigiflex polyurethane acrylate (PUA) molds with engraved nanoscale patterns were used to transfer metal layers (Au or Al) to flexible polyethylene terephthalate (PET) substrate. Transfer process was performed sequentially for the metal layers on ridge and valley regions of the mold, resulting in a dual-scale metal transfer from a single master. A simple metal wire grid polarizer was fabricated and analyzed using this method.

SiO₂-based variable microfluidic lenses were fabricated by femtosecond laser lithography-assisted micromachining (FLAM). Optofluidic devices have attracted much interest because the adaptive nature of liquids in microfluidics enables unique optical performance that is not achievable within all solid state devices. SiO₂-based microfluidic devices are, particularly, attractive due to high transparency, physical and chemical stabilities. However, it is generally rather difficult to form the microstructures in microchannels because photolithography process is limited to planar substrates. In our study, we fabricated SiO₂-based variable microfluidic lenses, which had micro-Fresnel lenses inside the channels, by using FLAM, which was a combined process of nonlinear lithography and plasma etching. The resist patterns of the Fresnel lenses were directly written inside chemically amplified negative-tone photoresist on SiO₂-based microchannels of 250 μm width and 6 μm depth using femtosecond laser-induced nonlinear optical absorption. Following that, the patterns were transferred to the bottom of the channels by using CHF₃ and O₂ mixed plasma. SiO₂-based Fresnel lenses with smooth surface were formed on the bottoms. When the channel was filled with the air, the focal spot was observed 2020 μm from the lens surface. By injecting silicone oil into the channel, the incident light was switched to the dispersed.

Organic dye doped polymer photonic crystal band-edge lasers, fabricated by combined nanoimprint and photolithography, are applied as evanescent-wave refractometry sensors. The emission characteristics of the lasers are altered in two ways, when the refractive index of the cladding is changed. Not only does the emission wavelength change, with a sensitivity of 1 nm per 10^-2 refractive index units, but also the relative emission intensity along the two symmetry directions of the rectangular device. The latter phenomenon is caused by the interplay between the symmetry of the triangular photonic crystal lattice and the rectangular device shape. This causes two of the three emission axes expected from the photonic crystal geometry to collapse into one. The optical losses of these two modes are influenced in different ways when the refractive index of the cladding is altered, thus also causing the emitted intensities along the symmetry directions to change. This suggests an integrated sensing scheme, where intensity is measured rather than emission wavelength. Since intensity measurements are simpler to integrate than spectrometers, the concept can be implemented in compact lab-on-a-chip systems.

Ultrafast laser micromachining is a promising candidate for micro- and nano-fabrication technology. Due to the high precision of femtosecond ablation, laser-machined features can be added to devices prototyped by lithography. To accomplish that, parametric studies of laser interrogation of materials of interest are necessary. We present femtosecond laser ablation studies of glass, PDMS, fused silica, and diamond films. Samples were ablated by a 800 nm laser beam with pulse width of 200 fs laser and repetition rates of up to 250 kHz. Our results include single- and multi-pulse laser machining for fluidic and photonic devices. Feature size and structural dependences on ablation rates are discussed.

DNA is good material for generating nanoscale-creations including nano-structures and nano-machines because the DNA is capable of making specific bonds depending on the sequences. The capability is helpful for programming behavior of the creations. Yurke et al. demonstrated a nanomachine called DNA tweezers [B. Yurke et al., Nature, 406, pp. 605 (2000).], which is closed by adding fuel-DNA and opened by adding another strand of DNA. This paper describes on state-transition of DNA nanomachines using photonic signals and shows the primary results of experiments. The use of photonic signal offers a method for parallel and local operation of DNA nanomachines depending on information from the outside of the solution. This idea is applicable to control nano-world based on photonics techniques. Azobenzene-tethered DNA is used for photonic operation. The form of the azobenzene is converted to cis-form under ultraviolet irradiation and trans-form under visible-light irradiation, and our scheme is based on the dependence of the binding strength of the azobenzene-tethered DNA and its complementary DNA on the form of the azobenzene[H. Asanuma et al., Nature Protocols, 2, pp. 203 (2007).] . Two types of DNA nanomachines controlled through photonic signals were investigated. One is a stepwise-growth type and the other is a self-contained type. The experimental results show that the state of the DNA nanomachine is changed after ultraviolet irradiation and visible-light irradiation. We succeeded to operate the self-contained type of DNA nanomachine no less than ten cycles.

We have previously demonstrated strong room-temperature luminescence at 1540 nm from erbium-doped amorphous silicon oxycarbide (a-SiC_xO_yH_z:Er) materials. In this study, pertinent details are presented regarding the role of growth conditions and post-deposition thermal treatment in engineering the structural and optical characteristics of these novel Si-based materials for optimized luminescence performance. Three different classes of a-SiC_xO_yH_z materials were synthesized by thermal chemical vapor deposition, as classified by their carbon and oxygen concentrations: SiC-like; Si-C-O; and SiO₂-like. Fourier-transform infrared spectroscopy, x-ray photoelectron spectroscopy, nuclear reaction analysis, and spectroscopic ellipsometry were used to characterize the effects of thermal annealing, as performed at temperatures in the range of 500 - 1100°<i>C</i>, on the structural and optical properties of the resulting films. As the material evolves from the SiC-like, through the Si-C-O, to the SiO₂-like matrix, the mass density and refractive index are found to decrease, whereas the optical band gap actually increases. Thermal annealing also resulted in hydrogen desorption from and densification of the a-SiC_xO_yH_z films and in an accompanying decrease in optical gap and an increase in film refractive index. This work suggests that silicon oxycarbide could be a promising Si-based matrix for high-performance Er-doped waveguide amplifiers.

Low cost manufacturing of Cu(In,Ga)Se₂ (CIGS) films for high efficiency photovoltaic devices by the innovative Field-Assisted Simultaneous Synthesis and Transfer (FASST®) process is reported. The FASST® process is a two-stage reactive transfer printing method relying on chemical reaction between two separate precursor films to form CIGS, one deposited on the substrate and the other on a printing plate in the first stage. In the second stage these precursors are brought into intimate contact and rapidly reacted under pressure in the presence of an applied electrostatic field. The method utilizes physical mechanisms characteristic of anodic wafer bonding and rapid thermal annealing, effectively creating a sealed micro-reactor that ensures high material utilization efficiency, direct control of reaction pressure, and low thermal budget. The use of two independent ink-based or PVD-based nanoengineered precursor thin films provides the benefits of independent composition and flexible deposition technique optimization, and eliminates pre-reaction prior to the second stage FASST® synthesis of CIGS. High quality CIGS with large grains on the order of several microns are formed in just several minutes based on compositional and structural analysis by XRF, SIMS, SEM and XRD. Cell efficiencies of 12.2% have been achieved using this method.

The size-dependent and lamination-dependent I-V curves of nano-multiplication-region avalanche photodiode (NAPD) were measured with the sized of 100nm, 200nm, 1μm, and 10μm. The gain increases with the decrease of the multiplication-region size and illumination power. These data indicate the NAPD possesses the advantages of high gain and high sensitivity.

With nanotechnology becoming widely used, many applications such as plasmonics, sensors, storage devices, solar cells, nano-filtration and artificial kidneys require the structures with large areas of uniform periodic nanopatterns. Most of the current nano-manufacturing techniques, including photolithography, electron-beam lithography, and focal ion beam milling, are either slow or expensive to be applied into the areas. Here, we demonstrate an alternative and novel lithography technique - Nanosphere Photolithography (NSP) - that generates a large area of highly uniform periodic nanoholes or nanoposts by utilizing the monolayer of hexagonally close packed (HCP) silica microspheres as super-lenses on top of photoresist. The size of the nanopatterns generated is almost independent of the sphere sizes and hence extremely uniform patterns can be obtained. We demonstrate that the method can produce hexagonally packed arrays of hole of sub-250 nm size in positive photoresist using a conventional exposure system with a broadband UV source centered at 400 nm. We also show a large area of highly uniform gold nanoholes (~180 nm) and nanoposts (~300nm) array with the period of 1 μm fabricated by the combination of lift-off and NSP. The process is not limited to gold. Similar structures have been shown with aluminum and silicon dioxide layer. The period and size of the structures can also be tuned by changing proper parameters. The technique applying self-assembled and focusing properties of micro-/nano-spheres into photolithography establishes a new paradigm for mask-less photolithography technique, allowing rapid and economical creation of large areas of periodic nanostructures with a high throughput.

An influence of electron beam (EB) irradiation on the crack generation and propagation of transparent glasses are studied by using a standard indentation fracture method. The thin (less than 0.5mm) transparent glass is used for substrate of more than 100 inches crystal liquid display. However, it is difficult to product ultra thin and large-size substrate without fracture. Therefore, these glasses have been expected to enhance the fracture toughness of substrate for the displays. As results, EB irradiation, which is one of short-time treatments of dry process at low temperature, increases the crack nucleation energy of these glasses, although the EB irradiation does not change the crack propagation energy of these glasses. The EB irradiation generates dangling bonds in these glasses. Partial relaxation of the residual strain occurs around these dangling bonds in the silica network structure. If the inter-atomic distance of the stronger metal-oxygen pairs becomes optimum on the potential curve of these glasses, the relaxation increases the bonding energy of the network structure. Evidently, the enhancement of crack nucleation energy is mainly due to an increase in the bonding energy for the stronger metal-oxygen atomic pairs in the atomic network structure, as well as the relaxation of the network structure.

Higher performance is the main driver in the integrated circuit (IC) market, but along with added function comes the cost of increased input/output connections and larger die sizes. Space saving approaches aimed at solving these challenges includes two technologies; 3D stacking (3D-ICs) and flip chip assemblies. Emerging ICs require sub-micron scale interconnects which include vias for 3D-ICs and bump bonds for flip chips. Photolithographic techniques are commonly used to prepare templates followed by metal vapor deposition to create flip chip bump bonds. Both the lithography step and the metal properties required for bump bonding contribute to limiting this approach to a minimum bump size of ~10 μm. Here, we present a wet chemistry approach to fabricating uniform bump bonds of tunable size and height down to the nanoscale. Nanosphere lithography (NSL), a "soft" lithographic technique, is used to create a bump bond template or mask for nanoscale bumps. Electrochemical deposition is also used through photoresist templates to create uniform bump bonds across large area wafers or dies. This template approach affords bumps with tunable diameters from 100s of nanometers to microns (allowing for tunable interconnect pitch and via diameters) while the use of constant current electoplating gives uniform bump height over large areas (>1 cm²).

Quantum dot infrared photodetectors (QDIPs) promise improved performance over existing technologies in the form of higher temperature operation and normal-incidence detection. Variation in the size of self-assembled quantum dots leads to a broadened spectral response, which is undesirable for multi-color detection. Photonic crystal slabs can filter the transmission of normally-incident light using Fano resonances, and thus may be integrated with QDIPs to create a narrowband detector. Finite-difference time-domain simulations were used to optimize such a filter for QDIPs grown by metal-organic chemical vapor deposition. The simulations predict that the integrated detector could show up to 76% decrease in the detector linewidth, with a tunable peak location. These devices were then fabricated by standard optical lithography, however the spectral width of the integrated device was similar to that of the unfiltered QDIP. This is attributed to imperfections in the filter, so alternative fabrication methods are discussed for future processing.

Most material systems have parabolic band structures at the band edge, however away from the band edge the bands are strongly non parabolic. Other material systems are strongly parabolic at the band edge such as IV-VI lead salt semiconductors. The effects of this property can be ignored for bulk material and structures. However, we will show that its effect can't be ignored in the nanoscale range and it is important to calculate for and take into consideration the effects of this unique property in any design and analysis. Based on the energy dependent effective mass, a theoretical model was developed to conduct this study on several lead salt (IV-VI) laser nanostructures in the infrared region. The effects of non-parabolicity on the gain versus current density relation are a reduction in the current density needed for any given gain and an increase in the gain saturation level. The non-parabolicity of the bands in the growth direction lowers the values of the confinement factor relative to parabolic bands which in turn lowers the modal gain values. Finally, the effects of non-parabolicity on the threshold current are significant for short cavity lasers and decrease with an increase in the cavity length.

Post-growth techniques such as impurity-free vacancy disordering (IFVD) are simple and effective avenues to monolithic integration of optoelectonic components. Sputter deposition of encapsulant films can enhance quantum well intermixing through IFVD and an additional mechanism involving surface damage during the sputtering process. In this study, these two mechanisms were compared in a multi-quantum well structure. The compositions of different silicon oxy-nitride films were controlled by sputter deposition in different ambient gases. These different encapsulants were used to initiate IFVD in the same heterostructure and the observed intermixing is compared to the film properties.

Fresnel zone plates are important x-ray diffractive optics which offer a focusing resolution approaching the theoretical limit. In hard x-ray region, the refractive indices of all the materials are close to unity, which requests thick zone plate to achieve a reasonable efficiency. It makes high-resolution zone plate extremely difficult to fabricate due to its high aspect ratio. We report a LIGA-like fabrication process employing e-beam resist HSQ as the plating mold material, which is relative simply compared with traditional processes. 1-μm-thick gold zone plates with 80-nm-wide outermost zone have been fabricated with this process.

Biomimetic structures provided important clues for nano-synthesis in pursuit of enhanced performances. Here, we report a wide angle and broadband antireflection is observed on a 6-inch silicon nanotip array (SiNTs) substrate fabricated using a single step electron cyclotron resonance plasma etching technique. This subwavelength structure consists of the SiNTs with apex and bottom diameter of ~5 nm and ~200 nm, respectively, length of ~1600 nm and density of 10⁹/cm². This aperiodic array of SiNTs with geometry designed in the sub-wavelength level to demonstrate a low hemispherical reflectance of < 1% in the ultraviolet to infrared region. The antireflection property holds good for a wide angle of incidence and both, s and p, forms of polarizations of light. The effective refractive index distribution related to the structure of SiNTs is built. The equivalent three-layered thin films with gradient refractive index can be applied in interpretation of the low reflection phenomenon. The equivalent admittance of the system is shown to be near that of air even the wavelength is varied from 400 nm to 800 nm (or angle of incidence is varied from 25 to 70 degree). The configuration to have broadband and wide-angle antireflection is different from the previous design because the equivalent rare film adjacent to air in our case is much thinner than the requirement proposed by J. A. Dobrowolski. This near ideal antireflection property suggests enhanced performances in renewable energy, and electro-optical devices in defense applications.

The structural properties and morphology of ZnO nanoparticles obtained by hydrothermal method were studied. ZnO samples were obtained by hydrothermal method, in soft synthesis conditions, temperature of solution about 70°C, in presence of a bidentate ligand or a tensioactive agent. The resulted oxides morphologies were compared with the morphologies of ZnO samples obtained in absence of ligands or tensioactive agents. Samples present a hexagonal phase of ZnO with lattice parameters about a=0.32nm and c=0.5nm, values confirmed by XRD measurements. Morphological properties are studied using bright field images, measuring the nanoparticles diameter and nanopellets size.

To meet the requirement of the space applications, digital thrusters with larger scale units should be employed, which means that the dimension of each thruster unit should be further reduced. In this paper, the system function structure for the satellite attitude control is introduced and a micro arrayed thruster is designed to improve the ignition properties in tiny chambers. A four layers structure of the micro thruster unit is presented and the ignition resistor is studied in detail. The structural mechanics analyzing results and the fabrication sample are presented. As an important part, the solid propellant is analyzed and the prescription is presented. To improve the uniformity of the propellant loading, a special device is developed by which the propellant can be once loaded into the array. To test the performance of the thruster, we developed an optical measurement system based on a pendulum structure. The system principle is introduced and a series of mathematical model was established. The impulse measurement system based on laser interference is presented. By this system, the impulse property of the micro thruster based on the solid propellant is studied and the test results are analyzed.

The waveguides and light sources are essential building blocks in optofluidics. Here, we have developed the new approach to fabricate efficient waveguides and light sources by using two-phase stratified flow of dye containing liquid and air. The liquid-core/air-cladding (LA) waveguide can overcome some of major drawbacks of the liquid-core/liquid-cladding (L²) waveguide without losing its unique advantages. Specifically, stronger optical confinement, originated from the large refractive index contrast between core and cladding, enable us to achieve lower propagation losses and larger captured fractions (the amount of light to be coupled into the liquid core). In addition, the LA waveguides are free from diffusional mixing of the core and cladding fluids. The fluorescent LA waveguides can be fabricated by conventional poly(dimethylsiloxane) (PDMS) based soft lithography, which is compatible with the other parts of optofluidic devices. Therefore, the fluorescent LA waveguide can be easily integrated with precise alignment as an internal light source of optofluidic devices.

Biomolecular detection using Localized Surface Plasmon Resonances (LSPR) has been extensively investigated because these techniques enable label-free detection. The high-density metal nanopatterns with tunable LSPR characteristics have been used as refractive index sensing because LSPR property is highly sensitive to refractive index change of surroundings. Meanwhile, Colloidal lithography is a robust method for fabricating regularly ordered nanostructures in a controlled and reproducible way using spontaneous assembly of colloidal particles. In this study, nanopatterns on UV-curable polymer were prepared via colloidal lithography. Then, metallic nanograil arrays with high density were fabricated by sputtering noble metals such as gold and subsequent removal of residual polymers and colloidal particles. From Finite-Difference Time-Domain Method (FDTD) simulations and reflectance spectra, we found that multiple dipolar plasmon modes were induced by gold nanograil arrays and each mode was closely related with structural parameters. LSPR characteristics of gold nanograil arrays could be tuned by varying the fabrication conditions to obtain optimal structures for LSPR sensing. Sensing behavior of gold nanograil arrays was tested by applying various solvents with different refractive indices and measuring the variations of LSPR dips. Finally, gold nanograil arrays as LSPR sensors were integrated in optofluidic devices and used to achieve real-time label-free monitoring of biomolecules.

We have developed a novel method for patterning nanoscale composite hydrogel materials on silicon through electron beam lithography. Gold particles were introduced into poly N-isopropylacrylamide (PNIPAam) patterned by e-beam lithography. By including BAC, the polymer can covalently bond to the colloidal gold nanoparticles. Such composites can be stable for long periods of time. We describe the structure, quality, and properties of the resulting patterned hydrogel-nanoparticle composite films.

One-dimensional nanostructures, such as nanowires, nanoneedles, nanobelts and nanotubes, have been extensively studied in recent years. These fascinating structures have the excellent physical properties owing to their geometry with high aspect ratio and modify the light-matter interaction. However, the defects of these structures are the obstacles for the practical applications. We report the influence of the hydrogen peroxide (H₂O₂) treatment on the point defects and structural defects of ZnO nanorods grown on n-type silicon. The ZnO nanorod arrays are prepared by low-cost hydrothermal method and the H₂O₂ treatments are investigated in two different approaches. One is to immerse ZnO nanorod samples into H₂O₂ solution. The other is a pre-treatment of spin-coating H₂O₂ solution on the seed layer before the growth of the ZnO nanorods. In the first approach, we found that the ultraviolet (UV) emission peak of the ZnO nanorods photoluminescence (PL) spectra was strongly dependent on the immersion time. In the second approach, the H₂O₂ solution not only influences the quality of the seed layer, but also the amount of the oxygen interstitial defects in the ZnO nanorods grown thereon. As a result, the UV emission intensity from the ZnO nanorods is enhanced almost five times. These effects are attributed to oxygen desorption through oxidation-reduction reactions of hydrogen peroxide on the ZnO surface. The ZnO nanorod arrays with few oxygen interstitial defects are prepared by low-cost and low-temperature hydrogen peroxide treatments, which are compatible with glass and polymer substrates and expected to enable the fabrication of optoelectronic device with excellent performance.

One of the useful applications using NIL is the fabrication of antireflection structure (ARS) which has a sub-wavelength nanostructure similar to moth-eye below wavelength of visible light because the ARS can be used in anti-glare monitor, dashboards, and solar cells. The material selection of mold and resin in the NIL process for ARS is very important for the purpose of real application and mass production. Generally, the mold should have flexibility for continuous mass production and final structure should have strong durability under outdoor environment. In this work, the effect of single side and dual side patterning were investigated by change of pitch from moth-eye to photonic crystal on the flexible polymer substrate by using NIL. Then, the effect of fluorine resin with low refractive index was tested. Finally, a fabrication method of ARS of pitch of 250nm with high fidelity and accuracy using the high-resolution PDMS mold by aid of solvent mixing of low viscosity was presented. Generally, it is difficult for Sylgard PDMS to make nanopattern below 300nm pitch without special treatment.

A tunable wavelength filters with Bragg grating are fabricated on a flexible substrate by using a post lift-off process along with an absorbing layer in order to provide highly uniformity of Bragg grating patterns. When the Bragg grating is fabricated on a flexible substrate, the highly elastic property of polymer is favorable to obtain much wider tuning range than the silica fiber. The flexible Bragg reflector shows narrow bandwidth, which is convincing the uniform grating structure fabricated on plastic film. By stretching the flexible polymer device, the Bragg reflection wavelength is tuned continuously up to 45 nm for the maximum strain of 31,690 με which is determined by the elastic expansion limit of waveguide polymer. From the linear wavelength shift proportional to the strain, the photoelastic coefficient of the ZPU polymer is found.

The advantages of using electric fields to manipulate and assemble samples are the ability to control the force exerted on particles and the simplicity of fabrication. Electroosmosis, an electrokinetic effect from the interaction between ions in the electrical double layer and the electric field, has less dependency on material property compared to dielectrophoresis. The critical parameters in electroosmosis are electrical double layer, the strength of electrical field and the flow velocity field. In an attempt to find the correlation among these parameters, a 3D electroosmosis chip is fabricated with different collection chamber size. The chamber size varying from 100 to 1000 μm was defined via photolithography and the size effect on the accumulation efficiency and collection pattern were studied by numerical simulations and experiments. The amine-modified polystyrene fluorescent particles whose average size is 1μm were used for experiments. The results show that the collection efficiency is a combined effect of the strength of the tangential electric field and the flow velocity gradient. As the chamber size decreases, the strength of the tangential field decreases and then increases, but the gradient of flow velocity intensifies. For small chamber size, the tangential electrical field induces greater flow velocity and results in more high velocity region. This explains why the smaller chamber size has better collection efficiency than the larger chamber size. For electroosmosis collection, the size of the chamber is a critical parameter for efficiency consideration.

A series of self-organized InAs/GaAs quantum dots with spacer layer under different thermal-treat (annealing) temperature and environments were prepared by molecular beam epitaxy. They were investigated by atomic force microscope and temperature-dependent photoluminescence (PL). Results showed that the sample annealed at lower temperature has lager size quantum dots and smaller density of quantum dots. The size of quantum dots is getting smaller and the density of quantum dots is getting larger as the annealing temperature increase. Two broad PL peaks are attributed to the combined size distribution of the bimodal quantum dots.

Using split-step Fourior method, the effect of initial chirp of femtosecond laser pulse on supercontinuum generation in nanofiber is numerically simulated. The results show that the initial chirp of femtosecond laser pulse play different roles in normal or anomalous dispersion region. In anomalous dispersion region, the positive chirp is profitable for spectrum broading, and spectrum width increases with the chirp. The effect of initial negative chirp is opposite. However, in normal dispersion region, the negative initial chirp can also be used to broaden the spectrum compared with the case of zero chirp.

We synthesized CdTe nano crystals (NCs) in uniform sizes and in good quality as characterized by photoluminescence (PL), AFM, and X-ray diffraction. In this growth procedure, CdTe nano-crystal band gap is strongly dependent on the growth time and not on the injection temperature or organic ligand concentration. This is very attractive because of nano-crystal size can be easily controlled by the growth time only and is very attractive for large scale synthesis. The color of the solution changes from greenish yellow to light orange then to deep orange and finally grayish black to black over a period of one hour. This is a clear indication of the gradual growth of different size (and different band gap) of CdTe nano-crystals as a function of the growth time. In other words, the size of the nano-crystal and its band gap can be controlled by adjusting the growth time after injection of the tellurium. The prepared CdTe NCs were characterized by absorption spectra, photoluminescence (PL), AFM and X-ray diffraction. Measured absorption maxima are at 521, 560, 600 and 603 nm corresponding to band gaps of 2.38, 2.21,2,07 and 2.04 eV respectively for growth times of 15, 30, 45 and 60 minutes. From the absorption data nano-crystal growth size saturates out after 45 minutes. AFM scanning of these materials indicate that the size of these particles is between 4 - 10 nm in diameter for growth time of 45 minutes. XD-ray diffraction indicates that these nano crystals are of cubic zinc blende phase. This paper will present growth and characterization data on CdTe nano crystals for various growth times.