Su Shubin, Ye Xiaona, Liu Shijie, Zheng Yuanlin, Chen Xianfeng
Opt Express. 2021 Apr 12;29(8):11885-11891. doi: 10.1364/OE.422113.
Whispering gallery mode (WGM) optical microcavities are important building blocks in photonic integrated circuits. Operation of such cavities on specific lower- or higher- order transverse modes has much interest in application perspectives. Here, we demonstrate active mode selection by introducing defects in lithium niobate on insulator microdisks. A focused ion beam is applied to precisely inscribe nano slits into the perimeter of the microdisk. The transmission spectra can be significantly thinned out without severe quality factor degradation. Either fundamental or high-order transverse WGMs can be retained by properly designing the size and location of the defects. The approach may have promising applications in single-mode lasing and nonlinear optics.
回音壁模式（WGM）光学微腔是光子集成电路中的重要组成部分。此类微腔在特定的低阶或高阶横向模式下运行，在应用前景方面备受关注。在此，我们展示了通过在绝缘体上的铌酸锂微盘引入缺陷来实现有源模式选择。应用聚焦离子束精确地在微盘周边刻写纳米狭缝。传输光谱可以显著变窄，而不会严重降低品质因数。通过适当设计缺陷的尺寸和位置，可以保留基模或高阶横向WGM。该方法在单模激光和非线性光学方面可能具有广阔的应用前景。
