Physics students at UD are invited to engage in major research efforts with faculty members.  The research opportunities available give students the chance to complement their classroom studies with hands-on experience and prepare them for the post-graduate world.  The following topics are a sampling of current undergraduate research projects. 

• Title: Applied Nonlinear Optics
  Mentor: Dr. Powers 
  We use nonlinear optical techniques to frequency convert lasers to the near infrared.  The nonlinear frequency conversion is a tunable process so that broad spectral regions can be covered with a single system.  We are actively pursuing research projects that further develop the tunable light sources.  We are also pursuing new and novel applications based on the tunable light sources.
  
  
• Title: Automated Admittance Spectroscopy
  Mentors: Dr. Ahoujja and Dr. Berney
  In this project a student will be involved in the first phase of setting up the admittance spectroscopy experiment. The actual project is to fully automate all the components of the experiment for data taking using LabView.
  
  
• Title: Cavity ring-down spectroscopy (CRDS)
  Mentor:  Dr. Powers
  Cavity ring-down is a technique that measures a very small absorption of light. Ring down measurements are important for applications such as trace species detection where one wants to measure a small number of molecules in an air sample (parts per billion to parts per trillion).    The idea behind CRDS is to inject a pulse of light into a cavity.  Once in the cavity, the pulse slowly leaks out (because we use high reflectivity mirrors).  By measuring how long it takes the pulse to leak out of the cavity, or to "ring down," one can determine how much light was absorbed in the cavity.   The amount of absorption can then be related to the number of absorbing molecules in the cavity.  This project involves setting up the initial ring-down cavity and the associated data acquisition.  Once this is completed we will go to an ultra-sensitive mode that uses a continuous wave laser instead of a pulsed laser.
  
  
• Computer interfaced nonlinear systems and computer modeling of physical systems
  Mentor: Dr. Berney
  Nonlinear systems have very interesting properties.  The goal of this project would be to design a nonlinear oscillator, collect data from it, and compare its behavior with both computer models and analytic solutions. 
  
  
• Title: Entangled Photons
  Mentors: Dr. Peter Powers (Experimental Work) and Dr. Leno Pedrotti (Theoretical and Numerical Work)
  This could be a multiyear project involving experimental, theoretical, and numerical work. Initially the student would help to build a light source that generates entangled photons (entangled states of the EM field) and a set-up to measure the entanglement. This experimental work is appropriate for students of all levels. Students that have had or are taking quantum mechanics could also contribute to a theoretical and numerical description of the entanglement and measurement process.
  
  
• Title: From Quantum to Classical Physics
  Mentor: Leno Pedrotti
  The student would investigate the way in which quantum mechanics gives the same results as classical mechanics for macroscopic systems with many degrees of freedom.
  
  
• Title: Investigating the Acceleration of the Expansion of the Universe.
  Mentor: Dr. Leno Pedrotti
  In this project a student would research and come to understand the ideas and evidence underlying the recent curious discovery that the universe seems to be expanding at an accelerating rate. The student performing this project would learn some general relativity and astrophysics. The project would be mentored by Leno Pedrotti who is not an expert in this subject but rather seeks to increase his own understanding of this discovery.
  
  
• Title: LabVIEW development of Magneto transport lab
  Mentors:  Dr. Rex Berney and Elhamri 
  Silicon has long been the primary semiconductor material for electronic devices, but other semiconductors are now being used and other are being developed for use as transistors, optoelectronic devices and integrated circuits.  In this lab we will do Hall effect and resistivity measurements on these new semiconductor materials to characterize their electrical transport properties.
  
  
• Title: Magneto-optic trapping of rubidium atoms. 
  Mentor: Dr. Robert Brecha
  Currently Ben Johnson is working on this project.    Using the light from a pair of diode lasers along with a magnetic field, it is possible to capture and confine a sample of rubidium atoms in an evacuated cell.  The slowing (cooling) and trapping process reduces the temperature of the gas sample from ~300K to 100ƒY´K.  Even at these extremely low temperatures, however, the sample does not condense because the density is so low.
  
  
• Title: Measurements of the electrooptical coefficient in crystals and polymers
  Mentor: Dr. Yaney
  The electro-optic effect in materials characterizes the the change in refractive index due to an applied electric field.  This phenomenon finds important applications in optical communication devices such as modulators and directional couplers, which utilize crystals and electrically "poled" plymers.  With the help of two previous physics graduates, I have set up a measuring system that allows the measurement of the eo coefficient as a function of angle and at two or more wavelengths.  Much of the work will be centered on measuring poled polymer films in collaboration with the Nonlinear Optics Lab in the Materials Lab at WPAFB.
  
  
• Title: Optical rotation of light in sugar solutions.
  Mentor: Dr. Robert Brecha
  Polarized light traveling through certain solutions experiences a rotation in the plane of polarization that is dependent on the material, the pathlength, and on the wavelength of the incident light.  I would like to use several diode lasers at different wavelengths (probably four) to make a compact system for measuring the optical rotation characteristics of solutions, and to see if it is possible to determine concentrations and to identify different constituents of the solution using this technique.
  
  
• Title: Spectroscopy of molecular oxygen. 
  Mentor: Dr. Robert Brecha
  I have been concentrating my efforts on this experiment for several years.  Right now I am interested in collecting data on the amount of light absorbed by oxygen at various wavelengths.  The goal of the experiment is to extract absorption parameters from the data by doing a non-linear least-squares fitting.  This experiment consists of  quite a bit of computer work, as well as work with a laser diode system for taking data.
  
  
• Title: Thermal and optical admittance spectroscopy of wide band gap semiconductors
  Mentor: Dr. Ahoujja
  This project is a follow up of Automated Admittance Spectroscopy project. The conductance and capacitance of a semiconductor diode will be measured as a function of DC voltage input, temperature, frequency and light (energy).  These measurements will provide useful information regarding electronic property of defects in wide band gap semiconductors. 
  
  
• Title: Transport properties: Analysis of Hall data and mobility fitting
  Mentors: Dr. Ahoujja, Dr. Berney and Dr. Elhamri. 
  In this project a detailed mobility fitting will be performed on mobility data using commercial software such as Mathcad or Origin.  Dominant scattering mechanisms can be extracted from the mobility fitting in addition to the true background concentration in semiconductor materials. The fitting to the Hall concentration will yield valuable information such as donor/acceptor concentrations and their respective energy levels.
  
  
• Title: Two-photon absorption in rubidium.
  Mentor: Dr. Robert Brecha
  As an extension of the work on oxygen, I have begun setting up an experiment that has the goal of making precise measurements of the absolute frequency at which oxygen absorbs light, to a level of about one part in 108.  We will use a pair of transitions in atomic rubidium to serve as our standard reference, with which we will compare the frequencies of the oxygen absorption features.  The absorption in rubidium is a two-photon process, in which light at two different wavelengths is simultaneously absorbed. 
  
  
• Title: Web experiment development with web camera and LabVIEW interface
  Mentor:  Dr. Rex Berney
  It is possible to for LabVIEW to publish an experiment to the web.  Several examples are already available at the National Instruments web site as well as at other universities.  Possible experiments include a greenhouse effect experiment, a driven oscillator experiment, or other experiments slow enough to be effectively displayed with a web camera.
  
  

*Additional research opportunities exist at the University of Dayton Research Institute, either on campus or at Wright Patterson Air Force Base. Also, there are numerous research opportunities through SOCHE, the Southwestern Ohio Council Council for Higher Education. Check in the physics department for current announcements.