Computational Depth-resolved Imaging and Metrology

In this thesis, the main research challenge boils down to extracting 3D spatial information of an object from 2D measurements using light. Our goal is to achieve depth-resolved tomographic imaging of transparent or semi-transparent 3D objects, and to perform topography characterization of rough surfaces. The essential tool we used is computational imaging, where depending on the experimental scheme, often indirect measurements are taken, and tailored algorithms are employed to perform image reconstructions. The computational imaging approach enables us to relax the hardware requirement of an imaging system, which is essential when using light in the EUV and x-ray regimes, where high-quality optics are not readily available. In this thesis, visible and infrared light sources are used, where computational imaging also offers several advantages. First of all, it often leads to a simple, flexible imaging system with low cost. In the case of a lensless configuration, where no lenses are involved in the final image-forming stage between the object and the detector, aberration-free image reconstructions can be obtained. More importantly, computational imaging provides quantitative reconstructions of scalar electric fields, enabling phase imaging, numerical refocus, as well as 3D imaging

Medical Imaging of Microrobots: Toward In Vivo Applications

Medical microrobots (MRs) have been demonstrated for a variety of non-invasive biomedical applications, such as tissue engineering, drug delivery, and assisted fertilization, among others. However, most of these demonstrations have been carried out in in vitro settings and under optical microscopy, being significantly different from the clinical practice. Thus, medical imaging techniques are required for localizing and tracking such tiny therapeutic machines when used in medical-relevant applications. This review aims at analyzing the state of the art of microrobots imaging by critically discussing the potentialities and limitations of the techniques employed in this field. Moreover, the physics and the working principle behind each analyzed imaging strategy, the spatiotemporal resolution, and the penetration depth are thoroughly discussed. The paper deals with the suitability of each imaging technique for tracking single or swarms of MRs and discusses the scenarios where contrast or imaging agent's inclusion is required, either to absorb, emit, or reflect a determined physical signal detected by an external system. Finally, the review highlights the existing challenges and perspective solutions which could be promising for future in vivo applications

Conference on Binary Optics: An Opportunity for Technical Exchange

The papers herein were presented at the Conference on Binary Optics held in Huntsville, AL, February 23-25, 1993. The papers were presented according to subject as follows: modeling and design, fabrication, and applications. Invited papers and tutorial viewgraphs presented on these subjects are included

VETA-I x ray test analysis

This interim report presents some definitive results from our analysis of the VETA-I x-ray testing data. It also provides a description of the hardware and software used in the conduct of the VETA-I x-ray test program performed at the MSFC x-ray Calibration Facility (XRCF). These test results also serve to supply data and information to include in the TRW final report required by DPD 692, DR XC04. To provide an authoritative compendium of results, we have taken nine papers as published in the SPIE Symposium, 'Grazing Incidence X-ray/EUV Optics for Astronomy and Projection Lithography' and have reproduced them as the content of this report

Optical Coherence Tomography and Its Non-medical Applications

Optical coherence tomography (OCT) is a promising non-invasive non-contact 3D imaging technique that can be used to evaluate and inspect material surfaces, multilayer polymer films, fiber coils, and coatings. OCT can be used for the examination of cultural heritage objects and 3D imaging of microstructures. With subsurface 3D fingerprint imaging capability, OCT could be a valuable tool for enhancing security in biometric applications. OCT can also be used for the evaluation of fastener flushness for improving aerodynamic performance of high-speed aircraft. More and more OCT non-medical applications are emerging. In this book, we present some recent advancements in OCT technology and non-medical applications

Extended field-of-view ultrathin microendoscopes with built-in aberration correction for high-resolution functional imaging with minimal invasiveness

TB

Engineered nanostructures for metal enhanced fluorescence applications in the near-infrared

Recent advancements in fabrication techniques allow construction of nanostructures with well-defined features in nanometres scale. Tiny nanostructures that have features below the resolution of optical diffraction limit can now be made in the laboratory. The specific properties of those nanostructures with specific properties made from variety of materials allow us to study and explore many different properties that have never been observed while they are in bulk. One such phenomenon is localised surface plasmon resonance effect, which is exhibited by certain materials when in nanometric size. Their peculiar interaction with light is in such a way that the optical properties such as reflection and transmission deviate from typical characteristics and change according to the material involved and their shapes. Furthermore, this effect could also enhance the electric field in a specific area of the structure. This thesis is motivated by the attractiveness of the tunability of localised surface plasmon resonance and aims at exploring those properties by fabricating multiple types of nanostructures through a low-cost and versatile technique called nanosphere lithography. By improving the technique and combining with other fabrication techniques (such as oxygen plasma etching and argon ion milling), a large variety of nanostructures with hexagonal lattice like as nanocones, nanopencils, and nanofins arrays have been successfully created. Among them, three main types of nanostructure were selected for detailed study: nanotriangle, nanodisc, and nanohole-disc arrays. The distance between the adjacent nanoparticles were changed in those structures and strong interparticle coupling behaviours were observed as the distance between them becomes shorter. Current portable biosensing devices for in vitro studies are limited by the sensitivity limit of the detector, the poor quality of emitters and the size of the devices. In this thesis, the application of localised surface plasmon resonance for near infrared in vitro biosensing is explored. This is achieved through a mechanism called metal enhanced fluorescence. The techniques take advantage of the high electrical field strength and the resonance condition of the plasmon to enable a fluorophore to achieve brighter emission. The greater the resonance and electrical field are, the greater the emission amplification would be. Such effect makes it highly attractive for near infrared in vitro studies, which benefits from high optical penetration of common biology components such as water and lipids, but suffer from poor emission of existing fluorophores. Thus, enhancement of the emission signals through metal enhance fluorescence mechanism is an attractive route to obtain better signal to noise ratio in medical diagnostic, and improve detectability while at the same time reduce the need of a high sensitivity detector which can be costly and large in size. The three chosen nanostructures, i.e. nanotriangular arrays, nanodisc arrays and nanohole-disc arrays have shown marked enhancement in the emission of attached fluorophores up to 83x, 235x, and 411x respectively, making them highly attractive nanostructures for such application.Open Acces

Air Force Institute of Technology Research Report 2010

This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, Mathematics, Statistics and Engineering Physic