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Faculty Projects
The following is a list of projects proposed by CREOL, The College of Optics & Photonics Professors. After you have been selected for the REU program, you will be asked to choose to work on one of these projects.
Summer 2010
Ayman Abouraddy Lab-on-a-Fiber-Tip Imagine building an optical laboratory on the tip of a hair. That will be your task! This project will focus on building optical devices, such as micro-resonators, waveguides, gratings, etc., on the tip of a multi-material optical fiber. The resulting fiber will be capable of both delivering an optical beam to a remote location and performing local optical sensing of the environment at the tip with no additional optical components. The project will include building a system capable of fabricating the devices on the fiber tip in the core region. Two techniques will be tested: UV lithography and embossing. The student will also be involved in designing optical experiments to test the performance of these devices.
Michael Bass Q-switched Nd:YAG Laser Characterize an electro-optically Q-switched Nd:YAG laser over a wide range of temperatures and operating conditions. This laser is of a compact design and uses diode laser pump sources. The project will familiarize the student with laser energy , nanosecond pulse and beam distribution measurements. Any or all of these may depend on temperature and so, before delivering the device, it must be characterized. Local travel to near-by lab is required, so participant would need car. All travel expenses (gas, etc…) will be paid for.
Sasan Fathpour Two-photon PV Effect in GaAs The summer REU participant will be conducting research on two-photon photovoltaic effect in gallium arsenide (GaAs, a III-V compound semiconductor material). The student will be involved in characterization of fabricated GaAs optical waveguides with p-n junction diodes and analyzing the data to estimate the efficiency of two-photon photovoltaic effect in the material and comparing it with the efficiency in silicon. The student will get hands-on experience in measurement setups for photonic device characterization which involves infrared tunable lasers, Erbium-doped optical amplifiers, optical fibers and optical spectrum analyzers. The student will also learn how to model and analyze photovoltaic cells and how to apply a more advanced version of the theory of solar cells to a new class of photovoltaic devices. The student will be mentored by Dr. Lena Tirpak, a postdoctoral associate at CREOL and will be supervised by Dr. Sasan Fathpour, the director of the Integrated Photonic and Energy Solutions Laboratory.
David J. Hagan Nonlinear Optical Properties of Semiconductor “Quantum Dots” This research project is based on semiconductor quantum dots (QD) which are commercially available in many different sizes from well below the Bohr Radius (strong quantum confinement) to well above (no quantum confinement). These materials are of tremendous current interest for such diverse applications as low threshold semiconductor lasers and for biomedical imaging applications. The student will carry out a systematic study of the nonlinear refraction and Two-Photon Absorption of the QD verses the size of the micro crystals. Experimental methods involved would be Transition Electron Microscopy (TEM), the Z-Scan method and linear optical spectroscopy in order to determine the size distribution, n2 , and the linear absorption of the QDs. The student will study are core only (PbSe and PbS) and core-shell, (CdS/CdSe) quantum dots where for the latter the core made from one semiconductor is coated by a layer of a different material.
David J. Hagan Modeling and Experimental Optimization of Picosecond and Nanosecond Optical Parametric Oscillators and Amplifiers Optical parametric oscillators (OPOs) and Amplifiers (OPAs) are nonlinear optical devices that are capable of producing laser light over huge ranges and are becoming a very common form of tunable laser source. The NLO group has several of these devices and we plan to increase our understanding of how they work by modeling these numerically and using the results to optimize the outputs of the systems. The student will learn the principles of nonlinear optics and OPO/A systems and will develop and use numerical codes that will allow the better understanding of how to optimally configure our devices. The student will then (with some help) reconfigure, realign and test the devices for optimized output.
Florencio Eloy Hernandez Multiphoton Absorption of Metal Nanoparticles Dr. Hernandez has a particular interest for the study of multiphoton absorption processes of supramolecular assemblies with strong intermolecular electronic coupling and, the fundamental understanding of the nonlinear chiro-optical properties of optically active structures. While the former have already shown promising applications in multiphoton fluorescence imaging, 3-D optical data storage, sensor protection, 3-D microfabrication and photodynamic therapy, the later is expected to lead to a better comprehension of enantioselective processes in living systems and unveil significant principles of left-handed metamaterials at optical frequencies. In addition, he is engaged in the study of the physical-chemical and optical properties of nobel metal nanoparticles and their interaction with tailored organic molecules for biological imaging, photodynamic therapy, optical data storage and sensing. A main component of his research is, on one hand, the employment of metal nanoparticles to assist high order nonlinear absorption processes and gain control on decay rates through hybrid systems engineering. On the other hand, the development of novel chemical, explosive and biological sensors combining physical chemistry, optics, spectroscopy and surface Plasmon resonance in a new interdisciplinary arena known as nanosciences.
Pieter G. Kik Angle Controlled Surface Plasmon Excitation in Metal-dielectric Layered Systems Surface plasmons are guided optical surface modes that can occur at a metal surface or a metal-dielectric interface. Due to their nanoscale mode size and operation at visible to near-infrared frequencies, surface plasmons are considered for use as novel optical channels on for example integrated circuits. In addition, surface plasmons are used in highly sensitive biosensors. In this project the aim is to develop a simple setup for exciting surface plasmons in an inverted optical microscope, and measuring the surface plasmon properties (wavelength, damping) of a metal film, and – time permitting – dielectric coated metal films. Knowledge of these parameters is important for understanding the potential of these structures for on-chip optical interconnects. The project would involve using a motorized mirror to direct HeNe laser light into the inverted microscope at specific angles onto a metal coated sample. Light reflected from the sample will be sent to a thermoelectrically cooled CCD array for analysis. Excitation of surface plasmons will be observable as a dramatic reduction in reflected intensity at specific incidence angles of the light. By measuring the angle dependent reflectivity it will be possible to extract information on the plasmon propagation on dielectric coated metal films.
Stephen Kuebler Fabrication and Characterization of a Nanophotonic Sensor In this project, the REU student will participate in the development and application of direct laser write (DLW) as a means for making a new type of nanophotonic sensor in which a 3D photonic crystal is fabricated directly on the end of an optical fiber. The photonic crystal surface will be chemically functionalized so that the material can respond optically to the presence of a target analyte. Light generated will be efficiently collected and guided by the photonic crystal into the fiber, for detection and measurement at the other end. The student will gain experience in optics, direct laser writing, nanotechnology, and optical materials chemistry.
Martin C. Richardson Spectral imaging of laser-induced plasma of organic material in reactive atmosphere In order to improve the performance of the Laser-Induced Plasma (LIP)-based technologies relying on the plasma composition (analytical as LIBS or applicative as LPD) and to understand the formation of (potentially harmful) nanoparticles by a LIP technique, the need of a better understanding of the chemical recombination mechanisms in the plasma is primordial. Since the energy levels involved are electronic and vibrational, a systematic spectroscopic study in the near-ultraviolet, visible and IR regions is imperative. The goal of this project is to obtain a 3D+1 spatial and time resolved map of the emitting species in the laser-induced plasma emission from an organic material in a reactive atmosphere thanks to their emission spectrum. The inversion algorithm will then be a reference for spectroscopic imaging in our laboratory for further studies in laser spectroscopy. Expectations: Acquisition of 2D emission maps (resolved in time) and their Abel inversion to obtain a complete understanding of the temperatures (electronic, ionic, atomic and molecular) and diffusion coefficients of the constituents of the plasma.
Martin C. Richardson Time resolved interferometric imaging of the laser-induced plasma electronic density Laser-induced plasmas are used in spectroscopy for determining the composition of solid surfaces, gases and/or liquids. Their emission can be inverted to provide their chemical composition. This inversion can be done only if the thermodynamics of the plasma are known: temperatures and electronic density. The temperatures (electronic, ionic, atomic and molecular) can be deduced, with a good accuracy, from the spectrum itself. The electronic density can be measured with much more accuracy than the spectral emission by mapping the variations of the refractive index. We use phase measurement by interferometry. The goal of this project is to obtain a 3D+1 spatial and time resolved map of the electronic density in the laser-induced plasma from an organic material. The experimental apparatus and the inversion algorithm will then be a reference for space and time resolved phase measurements of transparent media in our laboratory for further studies on plasmas and fluids. Expectations: Acquisition of 2D interferometric maps (resolved in time) and their Abel inversion to obtain a complete understanding of the electronic density of the plasma.
Martin C. Richardson Characterization of GMRF using 2µm ASE Source Introduction The theory of Guided Mode Resonance Filters (GMRFs) stems from discoveries R. W. Wood made in 1902 concerning variations in the intensity of the diffracted spectral orders over a narrow frequency range. Wood discovered two separate anomalies, the first described by Rayleigh in 1907 concerns the variation of intensity of diffracted orders when orders appear or disappear. The second theory, describing the resonance anomaly seen by Wood was explained by Hessel in 1965. GMR occurs when a diffraction grating couples the diffracted orders into guided modes in a waveguide structure. A resonance feature can be created when the guided mode leaks back onto the incident wave because of index modulation of the waveguide. GMR filters have shown promise as stable narrow linewidth feedback elements for fiber lasers due to the ability to tailor diffraction gratings to narrow the linewidth and select wavelength over a broad range. GMRFs, used as an external feedback element for the current Tm doped silica fiber, were fabricated at UNC-Charlotte. These GMRFs consisted of a fused silica substrate with a PECVD deposited SixNy waveguide layer, and a diffractive array of holes in a hexagonal lattice configuration, etched into a PECVD grown top layer of SiO2. A two dimensional diffraction grating was produced by way of a hexagonal hole-array patterns. Wavelength and resonance properties are varied by changes in hole size, spacing and waveguide layer thickness. A set of filters were designed to operate at around 2 μm with a spectral reflectivity of ~ 0.4 nm (FWHM). Expectations: The student will carry out and provide a series of transmission spectra of a variety of GMRFs with assistance of one of the graduate students.
Martin C. Richardson End-pumped Yb-doped GG IAG super large mode area fiber laser Introduction: Unlike a conventional optical fiber the refractive index in the core of an index anti-guiding (IAG) optical fiber is lower than that of its cladding. No classical index guided fiber modes can propagate in IAG fibers as a consequence of its index profile; total internal reflection can never occur in the fiber core, and thus light propagating in the core will always experience some loss. However, gain guiding (GG) can be achieved when gain is introduced to the fiber core. This occurs because the gain in the core compensates for the loss resulting from the IAG. This compensation results in gain guided index antiguided (GGIAG) modes in the fiber. Larger fiber core sizes can be achieved in GG IAG fibers than in traditional fibers because the guiding mechanism of these modes is weaker than traditional index guiding. These larger achievable core sizes can lead to higher CW or peak powers without deleterious nonlinear effects or catastrophic optical damage to the fiber core. Recently diode end-pumped Nd:GGIAG fiber lasers have been reported in fibers with cores varying from 200 to 400 μm with an M2 < 1.5. Yb is expected to have lower quantum defect than that for Nd, resulting in lower thermal issues. We envision to perform characterization and laser demonstration in Yb-doped GAIG fiber. Expectations: The student will perform and provide a series of characterizations of Nd and Yb doped GG IAG fibers with support provided by a graduate student.
Winston Vaughan Schoenfeld Binary Cubic Oxides for Deep-UV Applications Our group has been pioneering the growth of a new series of oxide semiconductors that have the potential overcome the existing barrier of high efficiency semicoductor devices operating in the solar-blind/deep-UV spectral region. The REU participant will be trained and responsible for the characterization and testing of these compounds, providing the critical data needed to determine the band gap energy of the verious alloys as a function of composition. Techniques such as spectrophotometry, atomic force microscopy, and x-ray diffraction will be utilized.
Eric W. Van Stryland Z-Scan of Nonlinear Materials by White Light The purpose of this project is to demonstrate the ability to create a stable White Light Continuum (WLC) for use in performing Z-scan to characterize the nonlinear optical properties of materials. This method has the potential for being favored over traditional Z-scan techniques by significantly reducing the amount of time spent realigning the system after each change in wavelength. This will be particularly useful in identifying nonlinearities in materials with unknown properties.
Shin-Tson Wu Liquid Crystal Systems The Photonics and Display Group at College of Optics and Photonics, University of Central Florida, focuses on following five subjects: 1) adaptive liquid crystal and liquid lenses, 2) photonic crystal fibers and bio-inspired photonics, 3) laser beam steering, 4) liquid crystal molecular engineering, and 5) liquid crystal display devices and modeling. The REU participant is expected to closely interact with our Ph.D. students and research scientists to explore new science and technology and generate high quality publications. The specific topic for the project will fall into one of the five listed subjects above. We will have group meeting every week to share our progress and to stimulate ideas from each other. In addition to actively participating in the research, the REU participant will be trained to make effective oral presentations.
See projects from other years: 2010| 2009| 2008| 2007| 2006| 2005| 2004| 2003| 2002| 2001|
