This presentation will be centered around the photorefractive effect, particularly, photorefractive beam coupling. Over the years, we have improved beam coupling in various geometries using novel photorefractive materials. Both inorganic and hybrid (organic-inorganic) photorefractive materials will be discussed, as well as the methods of improving these novel materials to give more efficient beam coupling. Techniques to increase the space charge field and the optical gain will be explored for inorganic systems; the enhancement of the beam coupling gain in liquid crystal photorefractive hybrids through the use of ferroelectric nanoparticles will also be explored, with an emphasis on the production and characterization of 9 nm ferroelectric nanoparticle – a size that has never been achieved in the past.
Departmental Colloquium : Novel Photorefractive Materials for Beam Coupling Applications, Dr. Dean R. EvansWhen: Thursday, March 31, 2011 4:00 pm - 5:00 pm Where: Physics 202
When: Thursday, April 7, 2011 2:00 pm - 3:00 pm
Where: CSP Conference Room (322)
Departmental Colloquium : Testing the Limits of Complex Organic Chemistry in the Interstellar Medium, Dr. Susanna Widicus-WeaverWhen: Thursday, April 7, 2011 4:00 pm - 5:00 pm Where: Physics 202
Fundamental biological molecules such as amino acids and sugars have been discovered in meteorites, but none of these species have yet been definitively detected in the interstellar medium (ISM). While both the number of detected interstellar molecules and their chemical complexity continue to increase, understanding of the processes leading to their formation is lacking. Recent chemical models suggest that organic radicals formed during the photolysis of interstellar ices provide the building blocks for the larger organic molecules found in star-forming regions. In order to investigate these interstellar prebiotic chemical pathways, we are developing a terahertz (THz) cavity ringdown spectrometer to study the unstable, reactive molecules that are key reaction intermediates. In this talk, I will present the initial results of the instrument development and spectroscopic studies. I will also outline our future plans for this instrument and the link to our ongoing projects in observational astronomy and astrochemical modeling.
NanoSEC Seminar : Investigating the Interaction of Ultrashort Laser Pulses with Optical Materials and Components, Dr. William DennisWhen: Friday, April 8, 2011 4:00 pm - 5:00 pm Where: Riverbend Research South Laboratory Auditorium
Modern table-top laser systems are capable of generating ultrashort optical pulses with sufficiently high intensity to induce nonlinear optical effects in many of the materials (including air!) that are used in the construction of optical components and systems. In this talk we describe how two of the techniques of computational optics can by provide insight into the complex dynamics that occurs at high intensities.
Firstly we describe how a modified 3+1D nonlinear Schrodinger equation coupled to a rate equation for the plasma density in the dielectric material can be used to simulate pulse propagation and plasma formation in fused silica. In particular we analyze the influence of pulse-shape and beam geometry on the formation of the electron plasma and hence modification in the bulk material. Secondly we use the finite difference time domain (FDTD) technique to simulate ultrashort optical pulse propagation through
When: Thursday, April 14, 2011 4:00 pm - 5:00 pm
Where: Physics 202
In recent years, computer scientists and physicists have begun to investigate the possibility of a computer whose hardware utilizes quantum phenomena, such as superposition and entanglement. There has developed a notion of a quantum algorithm, and examples are known of computational problems whose solution can be carried out in significantly less time by a quantum algorithm than by the currently best known traditional algorithm. The lecture has the goal of giving the audience a succinct and meaningful definition of a quantum computer, some appreciation of what all the fuss is about, and the capability of interpreting future developments.