Strain engineering of exciton-polaritons in 2D Semiconductors

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Nontechnical DescriptionAtomically thin two-dimensional (2D) semiconductors, owing to their unprecedented strong interaction with light have become a very attractive material platform for applications in photonics. From a fundamental standpoint, they demonstrate a wide array of phenomena including the regime of strong light-matter interaction where the system exhibits both the properties of light and material excitation. Such hybrid systems have potential applications in quantum technologies in the solid state that allow them to take on the best properties of matter and light. Due to the atomic thickness of these 2D materials, strain presents a unique approach to enhance the optoelectronic properties. This research is focusing on using strain to control the optoelectronic properties of these hybrid systems and to explore emergent properties that arise when strain is introduced in a lattice geometry. Such lattice of half-light half-matter systems can enable simulation of other quantum systems which are hard to simulate on a classical computer. Other potential application areas include realizing light-based circuits and switches which could conceivably operate at the level of a single particle of light. The project aligns with the NSF Big Idea of “Quantum Leap.” It will train graduate and undergraduate students and expose students from local area middle schools to the wonders of light and nanomaterials. A highlight among the outreach activities is a hands-on 2D materials workshop for undergraduate students at City College and a series of demonstrations for local area middle school.Technical DescriptionExciton-polaritons, hybrid states of electronic material excitations and photons demonstrate a wide array of rich physical phenomena. They are a potentially good platform for solid state quantum nonlinear photonics. In this project the research team will utilize the ability of 2D materials to withstand large strains to manipulate excitons and exciton-polaritons formed in optical microcavities embedded with atomically thin semiconductors. Extremely large strain via substrate engineering is induced to control strain patterns, manipulate exciton and polariton diffusion and finally enhance their nonlinear interactions for realizing correlated states of polaritons and their lattices. Specifically, 2D transition metal dichalcogenides embedded in strain engineered microcavities are used in the studies. Their linear and non-linear optical properties are investigated using combination of steady state, time resolved and Fourier space spectroscopy.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.