2024/11/11 by Lekshmi Eswaramoorthy, Parul Sharma, Eswaramoorthy, Lekshmi +14
Engineering · Physics and Astronomy · #Advanced Surface Polishing Techniques #FOS: Physical sciences #Integrated Circuits and Semiconductor Failure Analysis #Materials Science (cond-mat.mtrl-sci) #Optics (physics.optics) #Photonic and Optical Devices
paper · pdf · doi:10.48550/arxiv.2411.06947
openalex publication_date 2024/11/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Whispering gallery mode (WGM) microdisk resonators are promising optical devices that confine light efficiently and enable enhanced nonlinear optical effects. This work presents a novel approach to reduce sidewall roughness in SiO\textsubscript2 microdisk resonators using focused ion beam (FIB) polishing. The microdisks, with varying diameter ranging from 5 to 20 μm are fabricated using a multi-step fabrication scheme. However, the etching process introduces significant sidewall roughness, which increases with decreasing microdisk radius, degrading the resonators' quality. To address this issue, a FIB system is employed to polish the sidewalls, using optimized process parameters to minimize Ga ion implantation. White light interferometry measurements reveal a significant reduction in surface roughness from 7 nm to 20 nm for a 5 μm diameter microdisk, leading to a substantial enhancement in the scattering quality factor (Qss) from 3× 102 to 2× 106. These findings demonstrate the effectiveness of FIB polishing in improving the quality of microdisk resonators and open up new possibilities for the fabrication of advanced photonic devices.