Cryo-Compatible In Situ Strain Tuning of 2D Material-Integrated Nanocavity

Tunable nanophotonic resonators are an essential building block for material-integrated photonic systems and solid-state cavity quantum electrodynamic experiments. Matching the cavity resonance with the material optical transition is crucial for enhancing the light–matter interaction, leading to various associated phenomena that have important implications in quantum optics and optoelectronics. However, our inability to precisely control the resonant wavelength of nanofabricated optical cavities necessitates the use of postfabrication dynamical tuning, which is a challenging prospect, especially in cryogenic environments required for various quantum optical effects. Here, we realize a large in situ strain tuning of an integrated monolayer WSe2–gallium phosphide cavity device. We demonstrated tuning an on-substrate cavity with a quality (Q)-factor of ∼3500 at ∼780 nm by ∼5 nm without any degradation of the Q-factor at cryogenic temperature. The tunable cavity modes are manifested as cavity-enhanced monolayer exciton photoluminescence.