Controlling molecular processes with strong light-matter interactions

Photonic control of chemical reactions is a long-standing goal of physical chemistry with the potential to revolutionize chemical synthesis. Photonic control schemes have historically used targeted electromagnetic fields to steer chemical reactions through a preferred pathway, enabling selective chemical transformations without the need for synthetic modifications to the molecular structure or environment. However, the broader applications of schemes like mode-selective chemistry and coherent control are spoiled by rapid energy dissipation. As a result, only simple, predominantly gas-phase systems have proven amenable to optically-driven chemical control schemes.

The emerging field of polariton chemistry may soon provide a new architecture for photonic control of molecular reactivity harnessing strong light-matter interactions engineered in optical cavities. Polaritons are mixed light-matter states that arise when the confined electromagnetic field of an optical cavity interacts strongly with a bright transition of a molecular ensemble. A considerable body of experimental and theoretical work has already demonstrated that strong coupling can dramatically alter intracavity molecular processes without external illumination. However, the mechanisms underlying cavity-altered chemistry remain unclear in large part because the experimental systems examined previously are too complex for detailed analysis of their reaction dynamics. Deriving the governing set of rules for chemistry under strong coupling is a necessary first step before we can construct practical polaritonic reactors.

Our lab is establishing a new body of experimental work to validate theories of cavity-modified chemistry. These problems demand surveys of computationally-tractable, strongly-coupled reactions with experimental methods that can directly track the time-dependent populations of reactants, transient intermediates, and products in specific quantum states. We use both ultrafast and high-resolution spectroscopic methods to follow the dynamical trajectories of benchmark solution-phase and gas-phase molecular processes under strong coupling. Our measurements will inform prospects for using the new degrees of freedom afforded by cavity coupling to direct increasingly complex chemistry.

Current Project Members

Condensed-phase polaritons: Dr. Ashley Fidler, Liying Chen, Alexander McKillop

Gas-phase polaritons: Jane Nelson

Recent Publications