Boron-nitride foam composite resonators

While boron-nitride foam (BNF) has shown remarkable properties, such as large surface area, wide bandgap, and high chemical and thermal stability, its realization as a resonator is a critical step toward its implementation into sensors, ultraviolet optical devices, and high-power systems. Here, we demonstrate BNF composite resonators. We first characterized the response of the resonators under mechanical loading, followed by their resonance excitation under the influence of Kelvin polarization force. In parallel, we built a model that clarifies the trends in the operation of our resonators. We found that the Kelvin polarization force induces a stiffening of the resonators, which allows resonance frequency tuning. Also, the Kelvin polarization force enables the excitation of BNF composites from a distance, while eliminating the need for high-precision fabrication and electrical wiring. Therefore, we uncover the fundamental physical behavior of BNF and pave the path toward its integration into advanced functional devices.