Part of the Oxford Instruments Group
Polariton devices based on van der waals materials


Microcavity exciton-polaritons are formed through the strong coupling between excitons and photons in a cavity. The strong coupling regime is exemplified by the formation of new eigenstates, upper and lower polariton branches (UPB and LPB) that show ant crossing characterized by an energy separation (Rabi splitting). Monolayer transition metal dichalcogenides (TMDs) have emerged as a new class of material that shows unprecedented strength in its interaction with light. Large excitonic binding energy and strong oscillator strength in TMDs with photons have led to the observation of strong light-matter coupling resulting in the formation of exciton-polaritons in microcavities even at room temperature. In this talk I will discuss the electrical control of polariton emission, formed by strong coupling between excitons in monolayer TMDs and microcavity photons. Polariton electroluminescence is recorded from a van der Waal heterostructure comprising of graphene-hBN-WS2-hBN-graphene embedded in a microcavity. Injected electrons and holes tunnel through the hBN barrier and recombine in the WS2 resulting in luminescence and reveals clear polariton branches. I will also talk about the modulation of exciton-photon interaction strength in a strong coupling regime due to doping induced changes in the monolayer TMD.

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Meet the Presenter

Dr Biswanath Chakraborty

Dr Biswanath Chakraborty
Assistant Professor, Indian Institute of Technology Jammu 

Dr Biswanath Chakraborty is an Assistant Professor at the Indian Institute of Technology Jammu since January 2020. His research involves studying fundamental aspects of light-matter interaction and developing novel optoelectronic devices.  He completed his PhD from the Indian Institute of Science, Bangalore and did his postdoctoral research at the City University of New York.

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