Tailoring the Phonon Polaritons in α-MoO3 via Proton Irradiation

Ya-Nan Zhang, Yuanjun Tang, Liujian Qi, Yanze Feng, Mengda Li, Junru An, Lei Wang, Huiping Zhu, Bo Li, Dabing Li and Shaojuan Li

Advanced Optical Materials 11, 16 (2023)
Phonon polaritons (PhPs) provide new prospects for the development of next generation nanophotonic devices due to the high optical confinement, low optical losses, and long lifetime. It is crucial to modulate the PhPs in already discovered materials in order to utilize PhPs efficiently and increase the device operability. In this work, oriented particle trace structures in α-MoO3 are generated where the dielectric functions are broken by proton irradiation. Those particle trace structures act as in-plane boundaries, launching and reflecting PhPs. In-plane needle-like PhPs in the intermediate state are obtained and finally the switching-off of PhPs via increasing the irradiation fluences is achieved. Furthermore, the switching-off PhPs are partly restored to original state by annealing. The method provides an opportunity to manipulate light at the nanoscale and construct in-plane PhPs reflectors with the potential to be used for polaritonic devices and circuits.