Wave optics analysis by phase-shifting real-time holographic interferometry

The purpose of this work is to study the potentialities in the phase-shifting real-time holographic interferometry using photorefractive crystals as the recording medium for wave-optics analysis in optical elements and non-linear optical materials. This technique was used for obtaining quantitative measurements from the phase distributions of the wave front of lens and lens systems along the propagation direction with in situ visualization, monitoring and analysis in real time. (C) 2008 Elsevier GmbH. All rights reserved.

Damage Characterization Using Guided-Wave Linear Arrays and Image Compounding Techniques

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Combining Monte Carlo methods with coherent wave optics for the simulation of phase-sensitive X-ray imaging

Phase-sensitive X-ray imaging shows a high sensitivity towards electron density variations, making it well suited for imaging of soft tissue matter. However, there are still open questions about the details of the image formation process. Here, a framework for numerical simulations of phase-sensitive X-ray imaging is presented, which takes both particle- and wave-like properties of X-rays into consideration. A split approach is presented where we combine a Monte Carlo method (MC) based sample part with a wave optics simulation based propagation part, leading to a framework that takes both particle- and wave-like properties into account. The framework can be adapted to different phase-sensitive imaging methods and has been validated through comparisons with experiments for grating interferometry and propagation-based imaging. The validation of the framework shows that the combination of wave optics and MC has been successfully implemented and yields good agreement between measurements and simulations. This demonstrates that the physical processes relevant for developing a deeper understanding of scattering in the context of phase-sensitive imaging are modelled in a sufficiently accurate manner. The framework can be used for the simulation of phase-sensitive X-ray imaging, for instance for the simulation of grating interferometry or propagation-based imaging.

Wave optics and atomics.

Physical optics.--Physical electronics.--Atomic physics.--Nuclear physics.

Optics-Based Quantum Information and Sensing Platforms Utilizing the Nitrogen-Vacancy Center in Diamond

Thesis (Ph.D.)--University of Washington, 2016-08

Design, Fabrication and Characterization of Passive and Active Polymer Photonic Devices

The rapid developments in fields such as fibre optic communication engineering and integrated optical electronics have expanded the interest and have increased the expectations about guided wave optics, in which optical waveguides and optical fibres play a central role. The technology of guided wave photonics now plays a role in generating information (guided-wave sensors) and processing information (spectral analysis, analog-to-digital conversion and other optical communication schemes) in addition to its original application of transmitting information (fibre optic communication). Passive and active polymer devices have generated much research interest recently because of the versatility of the fabrication techniques and the potential applications in two important areas – short distant communication network and special functionality optical devices such as amplifiers, switches and sensors. Polymer optical waveguides and fibres are often designed to have large cores with 10-1000 micrometer diameter to facilitate easy connection and splicing. Large diameter polymer optical fibres being less fragile and vastly easier to work with than glass fibres, are attractive in sensing applications. Sensors using commercial plastic optical fibres are based on ideas already used in silica glass sensors, but exploiting the flexible and cost effective nature of the plastic optical fibre for harsh environments and throw-away sensors. In the field of Photonics, considerable attention is centering on the use of polymer waveguides and fibres, as they have a great potential to create all-optical devices. By attaching organic dyes to the polymer system we can incorporate a variety of optical functions. Organic dye doped polymer waveguides and fibres are potential candidates for solid state gain media. High power and high gain optical amplification in organic dye-doped polymer waveguide amplifier is possible due to extremely large emission cross sections of dyes. Also, an extensive choice of organic dye dopants is possible resulting in amplification covering a wide range in the visible region.

A new micro-machined millimeter-wave and terahertz snap-together rectangular waveguide technology

A novel technique for micro-machining millimeter and submillimeter-wave rectangular waveguide components is reported. These are fabricated in two halves which simply snap together, utilizing locating pins and holes, and are physically robust, and cheap, and easy to manufacture. In addition, S-parameter measurements on these structures are reported for the first time and display lower loss than previously reported micro-machined rectangular waveguides.

Hands-on training in Nonimaging Optics for SME's: the SMETHODS experience

A 5-day training in Nonimaging Optics for European SME’s employees was carried out in June 2012 in the framework of the FP7 funded Support Action "SMETHODS". The training combined theoretical introduction and hands-on practice. The experience was very positive, and the lessons learned will improve the next scheduled sessions. Introduction The FP7 funded Support Action "SMETHODS" [1] is an initiative of seven European academic institutions to strengthen Europe's optics and photonics industry, which has started on 1 September 2011. Participation in training sessions is free for participants, who are selected with priority will be given to employees of small and medium sized European enterprises (SMEs). The consortium in SMETHODS is formed by seven partners that are the most prominent academic institutions in optical design in their countries. Through fully integrated collaborative training sessions, the consortium provides professional assistance as well as hands-on training in a variety of design tasks in four domains: (1) imaging optics, (2) nonimaging optics, (3) wave optics, and (4) diffractive optics. For each of this domains domain, 5-day training sessions are scheduled to be hold in different locations throughout Europe, four times in two years, the teach four times in a 2.5 years period.

Finite Element Modeling of Spiral Frequency Steerable Acoustic Transducers (FSATs) for guided waves based Structural Health Monitoring of plate-like structures

Structural Health Monitoring (SHM) is an emerging area of research associated to improvement of maintainability and the safety of aerospace, civil and mechanical infrastructures by means of monitoring and damage detection. Guided wave structural testing method is an approach for health monitoring of plate-like structures using smart material piezoelectric transducers. Among many kinds of transducers, the ones that have beam steering feature can perform more accurate surface interrogation. A frequency steerable acoustic transducer (FSATs) is capable of beam steering by varying the input frequency and consequently can detect and localize damage in structures. Guided wave inspection is typically performed through phased arrays which feature a large number of piezoelectric transducers, complexity and limitations. To overcome the weight penalty, the complex circuity and maintenance concern associated with wiring a large number of transducers, new FSATs are proposed that present inherent directional capabilities when generating and sensing elastic waves. The first generation of Spiral FSAT has two main limitations. First, waves are excited or sensed in one direction and in the opposite one (180 ̊ ambiguity) and second, just a relatively rude approximation of the desired directivity has been attained. Second generation of Spiral FSAT is proposed to overcome the first generation limitations. The importance of simulation tools becomes higher when a new idea is proposed and starts to be developed. The shaped transducer concept, especially the second generation of spiral FSAT is a novel idea in guided waves based of Structural Health Monitoring systems, hence finding a simulation tool is a necessity to develop various design aspects of this innovative transducer. In this work, the numerical simulation of the 1st and 2nd generations of Spiral FSAT has been conducted to prove the directional capability of excited guided waves through a plate-like structure.

Denisiuk-type reflection holography display with sillenite crystals for imaging and interferometry of small objects

A novel setup for imaging and interferometry through reflection holography with Bi12TiPO20(BTO) sillenite photorefractive crystals is proposed. A variation of the lensless Denisiuk arrangement was developed resulting in a compact, robust and simple interferometer. A red He-Ne laser was used as light source and the holographic recording occurred by diffusion with the grating vector parallel to the crystal [0 0 1]-axis. In order to enhance the holographic image quality and reduce noise a polarizing beam splitter (PBS) was positioned at the BTO input and the crystal was tilted around the [0 0 1]-axis. This enabled the orthogonally polarized transmission and diffracted beams to be separated by the PBS, providing the holographic image only. The possibility of performing deformation and strain analysis as well as vibration measurement of small objects was demonstrated. (C) 2007 Elsevier B.V. All rights reserved.

A Strip-Loaded Feed-Horn antenna

Design and development of a new feed -horn antenna with low sidelobe levels is reported . The E-walls of this antenna are fabricated with low -loss dielectric substrate , periodically loaded with thin conducting strips . The antenna is found to be simulating the radiation characteristics of metallic corrugated horns . This can be an ideal substitute for metallic corrugated horns with added advantages like light -weight and low production cost.

A Strip-Loaded Feed-Horn antenna

Design and development of a new feed -horn antenna with low sidelobe levels is reported . The E-walls of this antenna are fabricated with low -loss dielectric substrate , periodically loaded with thin conducting strips . The antenna is found to be simulating the radiation characteristics of metallic corrugated horns . This can be an ideal substitute for metallic corrugated horns with added advantages like light -weight and low production cost.