Van der Waals exciton-polaritons at near-infrared wavelength [Invited]

Exciton-polaritons, formed by the strong coupling between excitons and photons, have been widely explored in monolayer transition metal dichalcogenides. However, the study has been limited to the materials with a bandgap at visible wavelengths, and devices working at telecom wavelengths remain largely unexplored. Here, we report exciton polaritons based on a monolayer of MoTe 2 integrated with a planar cavity consisting of silver mirrors. An all-dry transfer method is applied to keep the air-sensitive monolayer, MoTe 2 , pristine. Moreover, we implement the angle-resolved spectroscopy on the device using the Fourier lens scanning method based on a line-array camera. Thanks to the large coupling strength of the exciton and the small mode volume of the cavity, the strong coupling persists up to 200 K. Our findings open up new possibilities for exploring polariton physics at telecom wavelengths and potential integration with optical fiber communication systems.