Millimeter wave sensing of materials part 1: on chip

We introduce millimeter-wave silicon photonic crystal cavities as a platform for perturbative sensing of nanoscale materials. As a dielectric-based platform, it is compatible with strong magnetic fields, unlike superconducting cavities, yielding it as a promising platform for the study of many materials in extreme environments. To establish performance, we cryogenically characterized a silicon photonic crystal cavity at 4.3 K, observing total quality factors exceeding 105 for a 96 GHz mode. Then, to showcase its sensing capabilities, we placed a thin graphite-hBN heterostructure at an electric-field antinode of the cavity, measured the response at room temperature and did quantitative analysis.