Perturbative sensing of nanoscale materials with millimeter-wave photonic crystals

TL;DR

This paper demonstrates millimeter-wave silicon photonic crystal cavities as a new platform for sensitive perturbative sensing of nanoscale materials, capable of operating in extreme environments and providing detailed material characterization.

Contribution

The work introduces a novel millimeter-wave photonic crystal cavity platform compatible with high magnetic fields and extreme conditions for nanoscale material sensing.

Findings

Achieved a quality factor exceeding 10^5 at 96 GHz at cryogenic temperatures.

Measured the perturbative response of a heterostructure, determining its conductivity.

Established the platform's potential for on-chip spectroscopy of nanoscale materials.

Abstract

We introduce millimeter-wave silicon photonic crystal cavities as a versatile platform for the perturbative sensing of nanoscale materials. This dielectric-based platform is compatible with strong magnetic fields, opening avenues for studying quantum materials in extreme environments where superconducting cavities cannot operate. To establish the platform's performance, we cryogenically characterize a silicon photonic crystal cavity at 4.3 K, achieving a total quality factor exceeding $10^5$ for a 96 GHz mode. As a proof-of-concept for its sensing capabilities, we position a hexagonal boron nitride-multilayer graphene (hBN-MLG) heterostructure at an electric-field antinode of the cavity and measure the perturbative response at room temperature. The heterostructure induces a significant change in the cavity's resonance, from which we extract a total sample conductivity of approximately $5.1\times10^6$~S/m. These results establish silicon photonic crystal cavities as a promising platform for sensitive, on-chip spectroscopy of nanoscale materials at millimeter-wave frequencies.