We report the fabrication and optical characterization of an air-suspended photonic crystal nanobeam cavity in yttrium-iron-garnet (YIG) realized by focused-ion-beam milling. YIG's combination of low optical loss and ferrimagnetism makes it highly attractive for quantum technologies, yet prior work has largely been focused on millimeter-scale spheres and simple microstructures, hindering true on-chip integration. Demonstrating nanometer-scale patterning in a suspended geometry therefore represents an important advance. Finite-element simulations predict that the same structure supports a flapping-type mechanical mode at Ω/2π≈1.52GHz and a backward-volume spin-wave mode at Ω/2π=11.59GHz under an in-plane bias field. Although we measure only the photonic resonance (intrinsic Q∼2×103) in this study, the device lays the groundwork for future exploration of coupled photon-phonon-magnon dynamics once higher optical quality factors are achieved.
@article{arxiv.2412.05361,
title = {Photonic crystal cavities based on suspended yttrium iron garnet nanobeams},
author = {Alireza Rashedi and Mehri Ebrahimi and Yunhu Huang and Matt J. Rudd and V. A. S. V. Bittencourt and John P. Davis},
journal= {arXiv preprint arXiv:2412.05361},
year = {2026}
}