The conventional atomic force microscope (AFM) is equipped with a single optical detection system. Probe-sample separation is determined in an independent deflection with respect to AFM z-translation experiment. This method of determining probe-surface separation is relative, susceptible to drift and does not provide real time separation information. The evanescent wave atomic force microscope (EW-AFM) utilizes a second, independent detection system to determine absolute probe-surface separation in real time. The EW-AFM can simultaneously acquire real-time force and probe-sample separation information using the optical lever and evanescent scattering detection systems, respectively. The EW-AFM may be configured with feedback on the optical-lever system for constant force applications or with feedback on evanescent wave scattering intensity for constant height applications. Scattering of the evanescent wave exponential decay profile is used to determine probe-surface separation. Sub-micron sized dielectric and metallic probes show exponential scattering profiles, micron sized polystyrene and borosilicate microspheres show non-exponential profiles when they are affixed beneath the cantilever tip. By affixing the microspheres to the end of the AFM cantilever exponential and non-exponential profiles were observed. The EW-AFM can be used to conduct force-distance and imaging experiments. The EW-AFM was used to measure the thickness of surfactant bilayers formed at the silica-solution interface using silicon nitride AFM tips. The presence of a refractive index difference between the surfactant bilayer and the solution does not influence the accuracy of the surfactant bilayer thickness measurement. The EW-AFM was used to scan a 2 x 2 micron area in constant height mode. The probe was brought to within 6 nanometers of a planar dielectric surface using the evanescent wave intensity as a height reference with accuracy of ± 1 nm. This capability may be utilized to observe charge heterogeneity at the solid-liquid interface with nanometer lateral resolution or to map chemical functional group heterogeneity based on perturbations to the electrical double layer. The EW-AFM evanescent scattering system has an absolute separation resolution of 0.3 nm compared to 1.0 nm relative separation resolution for the optical lever system. In constant scattering (constant height) mode the real time separation precision is about 2 nm. / Ph. D.

We operated focus ion beam instrument (FIB) to etch array of cylindrical holes, with the diameter smaller than the wavelength of visible, on the sliver film. The sample was probed with the tungsten light source and the transmission spectrum of visible-NIR range was recorded with traix550 spectrometer with a cooling CCD. The optical extraordinary properties, such as the light can be transmitted through the holes array with the diameter of the hole smaller than the wavelength of the incident light and the enhancement of the efficiency, of the transmission of the subwavelength holes array were discussed. In this study, the factors affected the transmission spectrum of the subwavelength hole array, e.g.: the arrangement of the holes array, the material of the thin film, the diameter of the hole¡Kand so on, were researched. Besides, we modulated the effective dielectric property of the cavity of the subwavelength holes with the thermal evaporation method. It was pointed out that effective dielectric property of the cavity also influenced the optical properties of extraordinary transmission spectrum. We believe that our research was helpful to understand the physical properties of the subwavelength holes array.

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Esta dissertação versa sobre a parcela evanescente que constrói uma série convergente e, desse modo, impossibilita sua permanência em uma forma última. O estudo da evanescência como a possibilidade de movimentar um corpo afirma a potência do infinito de uma vida finita e a impossibilidade da permanência a partir do movimento incessante do infinitamente pequeno. Afirmar a irredutibilidade do movimento a um ponto de chegada e a possibilidade da criação de um outro si ou de um si sempre provisório é considerado, neste estudo, um modo de inventar a vida. Com Foucault e Deleuze, apresenta-se um corpo como uma estrutura atravessada por linhas que operam e compõem instantaneidades, como forma em constante mutação. Trata-se de produzir ecos entre os domínios da filosofia e da matemática, na afirmação da diferença como aquilo que constitui um corpo. A impossibilidade da permanência é tomada como transgressão de limites impostos, ao considerar uma formação como a produção de infinitas formas. / This dissertation is about the evanescent parcel that builds a convergent series and, this way, precludes its permanence in an ultimate form. The study of evanescence as a possibility of moving an object affirms the potency of the infinite of a finite life and the impossibility of permanence from an incessant movement of the infinitely small. Affirming the irreducibility of movement to an arrival point and the possibility to create another form or an form always temporary is considered, in this study, a way to invent life. Departing from Foucault and Deleuze, an object is presented as a structure crossed by lines that operate and compose instantaneities, as a shape in constant mutation. It is about producing echoes between philosophy and mathematics, considering difference as what constitutes an object. The impossibility of the permanence is taken as a transgression of imposed limits, when it consideres a formation as a production of infiniteness forms.

In this paper, a parametric study of the airbrush deposition technique was investigated for the deposition biomolecular thin films. The airbrush parameters under investigation were intake valve opening, carrier gas pressure, distance between the airbrush and substrate, concentration of solution, vapor pressure of solvent, and hydrophobic/hydrophilic substrate surface. This study was assessed through the characterization of dried droplet residues of Bovine Serum Albumin (BSA) and of complete films of BSA by means of scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was determined that droplet size was mainly affected by carrier gas pressure and vapor pressure. The parameters intake valve opening, distance between the airbrush and substrate, and concentration of solution control the rate of spray, or solution flux, onto the substrate. Solution flux was determined to have the greatest impact on film roughness. This allowed for flexibility in the airbrush deposition technique to produce films with various substrate wetting rates. Low flux films were produced when the droplets dried on the substrate surface before the next droplet arrived. High flux films were generated when droplets on the surface arrive before subsequent droplets are given time to dry. Finally, as an extension of the results of these experiments, a practical application of the airbrush deposition technique was conducted using appropriate deposition parameters. An E. coli wave guide biosensor was produced on a glass substrate. A sandwich immunoassay was used to confirm E. coli capture.

Biosensor development has the potential to meet the need for rapid, sensitive, and specific detection of pathogenic bacteria from natural sources. An antibody-based fiber-optic biosensor assay to detect low levels of Vibrio vulnificus in estuarine waters following an enrichment step was developed. The principle of the sensor is based on an immuno-sandwich assay where an anti-V. vulnificus polyclonal capture antibody preparation was first immobilized on a polystyrene fiber-optic waveguide using a biotin-avidin association. The capture antibody is responsible for binding the target cells to the waveguide. Cyanine-5-conjugated anti-V. vulnificus polyclonal antibodies are subsequently allowed to bind to immobilized cells, and detection occurs when a photodetector collects emitted light (670-710 nm) from the fluorophore, which is excited with 635-nm laser light produced by the Analyte 2000 biosensor. Any detection signal greater than a pre-determined threshold signal is considered to be a positive detection event, while any signal lower than the threshold is considered no detection. This immunosensor assay proved highly specific when tested against whole cells and cell extracts from V. cholerae, V. parahaemolyticus, V. alginolyticus, and E. coli. isolates. Following a four hour enrichment in PNCC broth, and in a total of less than seven hours, the assay was able to detect cell extracts from as few as 100 V. vulnificus colony forming units suspended in sterile water. This method holds promise for detection of low numbers V. vulnificus and other autochthonous pathogens in estuarine waters.

The motion of dye molecules in the solution is highly influenced by the Brownian motion caused by the stochastic collisions with the solvents, and it results the fluorescence intensity fluctuation. The thesis study the fluorescence intensity fluctuation of dilute dye molecule (Rhodamine B) in methanol solution ( - ), under confocal and total internal reflection (TIR) microscopy configurations. Five parameters are used to probe the fluorescence characteristics: (1) the difference between confocal and the TIR configurations. The configuration influences the laser focusing area and consequently the intensity distribution. The effective focusing area in confocal configuration is an ellipsoid shape, while that of TIR configuration is a disk shape around the interface with depth 100-200 nm. It results the TIR configuration less background and higher concentration capability. (2) concentration. We control the concentration from much less than one molecule to more than one molecule in the effective focusing area, and we observe the change of burst intensity distribution. (3) the focus position. By changing the focusing position, we study the effective focusing region changes. (4) excited intensity, and (5) fluorescence correlation spectroscopy (FCS). Our results indicate that TIR configuration exhibits lower background, and is suitable to higher concentration solution. In addition, when the dye concentration in the focusing area is much less than 1, the FCS amplitude is no longer follow 1/N, but rather be proportional to N, where N is the concentration.

In this thesis the in-plane pattern distortion resulting from the use of Evanescent Near Field Optical Lithography (ENFOL) masks was investigated. ENFOL is a high resolution low-cost technique of lithography that is able to pattern features beyond the diffraction limit of light. Due to its use of the evanescent near field, ENFOL requires the use of conformable masks for intimate contact. Such masks can stretch and skew as they come into contact with silicon substrates and therefore distort the high resolution features patterned on them. It was desired to measure this distortion to ascertain the patterning performance of ENFOL masks and possibly correct for any uniform distortion found. To this end a sophisticated measuring process was successfully demonstrated. This involved the use of a Raith 150 Electron Beam Lithography (EBL) system with precision laser interferometer stage and metrology software module for automated measurements. Custom software was written for the Raith to enable it to take additional measurements to compensate for electron beam drift. Processing algorithms were then employed to using the measurements to compensate for beam drift and correcting for shift and rotation systematic errors. The performance of the in-plane distortion measuring process was found to have a precision of 60nm. With the ability to measure distortion, ENFOL masks were used to pattern substrates and distortion was found to be large, on the order of 1µm. This is much larger than desired for sub 100nm patterning as is expected of ENFOL. The distortions were non-uniform patterns of localised displacements. This, the observation of Newton's rings beneath a test mask and the observation of a single particle distortion across measurements of the same mask across different loadings in the EBL pointed to particulate contamination causing the distortion. In order to prove beyond doubt that particulate contamination was the cause of the spurious distortions, mechanical modelling using the Finite Element Method (FEM) of analysis was employed. The results from this matched the distortions observed experimentally, particles 20-40µm modelling the observed distortion.

Recent advances in nano technology have opened doors to several next generation devices and sensors. Characterizing nano particles and structures in a simple and effective way is imperative for monitoring and detecting processes at nano scale in a variety of environments. In recent years, the problem of studying nano particle interactions with surface plasmons or evanescent waves has gained significant interest. Here, a numerical model is presented to characterize nano-size particles and agglomerates near a metal or a dielectric interface. The methodology is based on a hybrid method, where the T-matrix approach is coupled with the image theory. The far field scattering patterns of single particles and agglomerates subjected to surface plasmons/evanescent waves are obtained. The approach utilizes the vector spherical harmonics for the incident and scattered fields relating them through a T-matrix. Effects of size, shape and orientation of the cluster on their scattering patterns are studied. An effort is made to distinguish particle characteristics from the scattering information obtained at certain observation angles. Understanding these scattering patterns is critical for the design of sensors using the surface plasmon scattering technique to monitor nano self assembly processes

Esta dissertação versa sobre a parcela evanescente que constrói uma série convergente e, desse modo, impossibilita sua permanência em uma forma última. O estudo da evanescência como a possibilidade de movimentar um corpo afirma a potência do infinito de uma vida finita e a impossibilidade da permanência a partir do movimento incessante do infinitamente pequeno. Afirmar a irredutibilidade do movimento a um ponto de chegada e a possibilidade da criação de um outro si ou de um si sempre provisório é considerado, neste estudo, um modo de inventar a vida. Com Foucault e Deleuze, apresenta-se um corpo como uma estrutura atravessada por linhas que operam e compõem instantaneidades, como forma em constante mutação. Trata-se de produzir ecos entre os domínios da filosofia e da matemática, na afirmação da diferença como aquilo que constitui um corpo. A impossibilidade da permanência é tomada como transgressão de limites impostos, ao considerar uma formação como a produção de infinitas formas. / This dissertation is about the evanescent parcel that builds a convergent series and, this way, precludes its permanence in an ultimate form. The study of evanescence as a possibility of moving an object affirms the potency of the infinite of a finite life and the impossibility of permanence from an incessant movement of the infinitely small. Affirming the irreducibility of movement to an arrival point and the possibility to create another form or an form always temporary is considered, in this study, a way to invent life. Departing from Foucault and Deleuze, an object is presented as a structure crossed by lines that operate and compose instantaneities, as a shape in constant mutation. It is about producing echoes between philosophy and mathematics, considering difference as what constitutes an object. The impossibility of the permanence is taken as a transgression of imposed limits, when it consideres a formation as a production of infiniteness forms.