Silicon stepped Euler-bending microdisk resonators with ultra-high experimental Q factors

Microresonators with a high quality ( Q ) factor and a small footprint constitute a cornerstone of cutting-edge fields including on-chip low threshold lasers, microwave photonics, and quantum information processing. However, for resonators at the scale of tens of micrometers, the experimental Q factor has long been limited to the order of 1 million. Here, we propose a silicon-based stepped Euler-bending microdisk resonator (MDR) that achieves record-breaking performance. This research introduces an innovative structural design approach that combines suspended architecture with multi-step sidewalls and Euler-bending boundaries to overcome fundamental limitations in conventional disk resonators. The device demonstrates an ultra-high experimental intrinsic Q factor of 4.8×10 7 while maintaining a compact footprint of merely 1.29×10 −3 mm 2 . Compared to state-of-the-art integrated resonators, the proposed MDRs truly break the constraints between the device size and Q factor. Furthermore, the proposed design methodology addresses critical challenges in achieving both ultra-high Q factors and fabrication tolerance in micrometer-scale devices. Consequently, the developed micrometer-scale ultra-high- Q resonator holds the potential to revolutionize on-chip high-density communication networks and unlock advanced signal processing. This work establishes a new paradigm for developing compact and high-performance optical resonators, which can be extended to diverse material platforms including silicon nitride and lithium niobate.