Monolithic temperature-insensitive high-Q Ta₂O₅ microdisk resonator

We demonstrate a temperature-insensitive high-Q tantalum oxide (Ta₂O₅) microdisk resonator fabricated using electron-beam lithography and inductively coupled plasma reactive-ion etching. The microdisks exhibit a loaded Q-factor of 4.25 × 10⁵ at 1,550 nm, which more than doubles (∼9.3 × 10⁵) following thermal annealing at 600 °C. Remarkably, the temperature-dependent resonant wavelength shift is suppressed to less than 10 pm/°C across a broad 100 nm bandwidth. Furthermore, the resonators maintain high optical stability under elevated input powers, with no observed degradation in optical properties such as extinction ratio or Q-factor. The combination of high Q-factors and exceptional thermal stability positions the Ta₂O₅ microdisk resonators as a promising platform for integrated photonic device applications, including on-chip narrow-linewidth lasers and precision sensing.