上海科技大学知识管理系统

Tantalum pentoxide (Ta2O5) is widely recognized as a promising material platform for photonic integration. This is primarily attributed to its exceptional properties including large bandgap of 3.8 eV, broad transparency window ranging from 300 nm to 8000 nm, high nonlinear refractive index of ∼7.2 × 10−19 m2/W, low optical loss, moderate refractive index of 2.05, low intrinsic material stress, compatibility with CMOS technology, and high solubility for rare-earth ions. However, dry etching of Ta2O5 is challenging and typically results in sidewall roughness with substantial scattering losses. Here, we report on fabrication of a high-Q whispering gallery mode (WGM) microdisk with a diameter of 120 µm and a loaded Q factor of 1.92 × 106 by femtosecond laser photolithography assisted chemo-mechanical etching (PLACE) on amorphous Ta2O5 film. Thanks to the suppression of sidewall scattering, the loaded Q factor is two orders of magnitude higher than the best reported value in dispersion engineered Ta2O5 microresonators. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.