David Shelton's Research Interests
My research aims to understand the structure and properties of materials using the tools of nonlinear laser spectroscopy. In the past, my laboratory has made measurements of gas-phase molecular hyperpolarizabilites to test and guide the development of methods for ab initio quantum chemical calculations; measured the nonlinear optical properties of organic molecular chromophores with possible applications in optical signal processing devices; studied the photochromic and photo-electro-chemical response of the bacteriorhodopsin molecule, a unique model biophysical system; and studied the motion of molecules in liquids using second harmonic light scattering spectroscopy.
The problem that will be addressed this summer is to measure and understand a slow molecular reorientation mode in polar liquids which was recently discovered by hyper-Rayleigh scattering measurements in my lab. This previously unobserved behavior may be the key to understanding the profound dynamic changes, with no apparent structural basis, which are seen in supercooled liquids and glasses. A summer student will help develop apparatus and run the experiment, with the aim of obtaining a fully resolved spectrum. The instrument development involves work with a pulsed single-mode laser and high resolution confocal and plane-parallel Fabry-Perot interferometers.