Development of Ultrafast Cavity-Enhanced Two-Dimensional Spectroscopy for Coherent Control Experimental Design

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

With support from the programs in Atomic, Molecular and Optical Experimental Physics (AMO-E), Chemical Structure, Dynamics and Mechanisms-A (CSDM-A) and Integrative Activities in Physics, Prof. Melanie Reber at the University of Georgia is increasing the sensitivity of a laser technique for studying and controlling molecules. The idea of using light to selectively control the breaking of a bond and to control the outcome of a chemical reaction is a long-standing dream. It could potentially provide new avenues to synthesize molecules or even create new molecules. In order to use light for a controlled synthesis, ideally one would have detailed knowledge about the molecular electronic, vibrational, and rotational energy landscapes and how they are coupled. One challenge with describing the molecular system for designing control sequences is if the molecule has complicated dynamics that are not well described by current computational chemistry or spectroscopic methods. This project will develop a spectroscopy-driven approach to designing coherent control experiments, specifically improving the sensitivity and resolution of two-dimensional spectroscopy through the use of optical enhancement cavities and frequency comb lasers. Two-dimensional spectroscopy provides information about the structure and dynamics of molecules, but currently can only be used on condensed-phase samples. Over the three years of the project, the research team will develop the capability to perform multidimensional spectroscopy on dilute species, enabling studies of small, isolated molecules without the effects of solvent, for example. The students working on this highly-technical project will gain valuable interdisciplinary training in electronics, optics, lasers, vacuum technology, programming, data analysis, CAD design, and quantum mechanics. This training will set the students up for successful careers in technical fields in industry and academia. In addition, the PI will start a yearly workshop aimed at students from local colleges, including several HBCU’s, to learn about chemistry and physics graduate school and the application process. The research team will develop a high-resolution and ultrafast two-dimensional spectrometer for characterization of vibrational and electronic coupling in molecules for a detailed molecular approach to designing coherent control experiments. The main goal of the project is to build the cavity-enhanced two-dimensional spectrometer with a visible pump and tunable visible probe with a dual comb detection scheme. They will use frequency comb lasers and techniques, including dual-comb detection, to increase the sensitivity and enable high-resolution spectral detection. The cavity-enhancement will improve the sensitivity of two-dimensional spectroscopy, such that dilute species in molecular beams can be studied with two-dimensional spectroscopy for the first time. This instrument will then provide new data on the structure and dynamics of gas phase molecules with the potential for ultrafast time resolution and high-precision frequency resolution to be used for coherent control experimental design. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.