Perturbative sensing of nanoscale materials with millimeter-wave photonic crystals

Kevin K. S. Multani; Zhurun Ji; Wentao Jiang; Siyuan Qi; Akasha G. Hayden; Gitanjali Multani; Sharon Ruth S. Platt; Emilio A. Nanni; Zhi-Xun Shen; Amir H. Safavi-Naeini

arXiv · 2602.17527

Perturbative sensing of nanoscale materials with millimeter-wave photonic crystals

Kevin K. S. Multani·Zhurun Ji·Wentao Jiang·Siyuan Qi·Akasha G. Hayden·Gitanjali Multani·Sharon Ruth S. Platt·Emilio A. Nanni·Zhi-Xun Shen·Amir H. Safavi-Naeini

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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.

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Kevin K. S. Multani, Zhurun Ji, Wentao Jiang, Siyuan Qi, Akasha G. Hayden, Gitanjali Multani, Sharon Ruth S. Platt, Emilio A. Nanni, Zhi-Xun Shen, Amir H. Safavi-Naeini. 2026-02-19. Perturbative sensing of nanoscale materials with millimeter-wave photonic crystals. https://arxiv.org/abs/2602.17527

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