Long-lived coherent Rabi oscillations in molecular polaritons and their application to ultrafast all-optical switching

Innovations in all-optical technologies hold the key to unlocking the next generation of faster and more efficient data processing and computing systems. Novel material platforms that can be controlled and manipulated using light are necessary building blocks for such technologies. One such platform is strongly coupled systems, where light and matter states coherently couple to form hybrid light-matter quasiparticles called polaritons. Polaritonic systems have already shown great promise in designing high-speed all-optical data processing systems. Achieving strong coupling has also been proposed as a basis for quantum information processing protocols, especially in the ultrastrong coupling regime where the strength of light-matter coupling becomes comparable to the energy levels of the interacting states. An important challenge in strongly coupled systems is the short-lived nature of the polaritonic coherence (and its time domain signature, Rabi oscillations), especially at room temperature. As a result, harnessing this short-lived regime for real-life implementation remains unrealized. The goal of this project is to experimentally observe long-lived coherent Rabi oscillations in the ultrastrong coupling regime and to demonstrate a novel ultrafast data processing operation using the Rabi oscillations. To achieve this, I will use state-of-the art ultrafast spectroscopy techniques to unveil the femtosecond-scale Rabi oscillation dynamics of a molecular polaritonic system at room temperature and demonstrate an optical switch that is an order of magnitude faster than state-of-the-art polaritonic devices. These results will address the knowledge gap in polaritonics in the ultrastrong coupling regime and spur research into harnessing coherent polariton dynamics for ultrafast all-optical applications. The outcomes of the project are expected to pave the way for future fast and energy-efficient quantum and all-optical information processing technologies.