Gate-tunable nanoscale negative refraction of polaritons demonstrated in van der Waals heterostructure

A new study led by Dai Qing's team from the National Center for Nanoscience and Technology (NCNST) of the Chinese Academy of Sciences (CAS) and Javier Abajo from the Institute of Photonic Sciences (ICFO) in Spain has shown a gate-tunable nanoscale negative refraction of polaritons in the mid-infrared range through a van der Waals heterostructure of graphene and molybdenum trioxide.