Wang Min, Wang Yun-Zhao, Xu Xu-Sheng, Hu Yun-Qi, Long Gui-Lu
Opt Express. 2019 Jan 7;27(1):63-73. doi: 10.1364/OE.27.000063.
We have studied the effect of geometry deformation on the mechanical frequencies and quality factors for different modes in the Whispering Gallery Mode (WGM) microresonators, that is unavoidable in the practical fabrication. The subsidence of the sphere and a more general condition with fewer symmetries and complex deformation of eccentricity, subsidence, and offset are first modeled in this paper, which could tune the mechanical frequency in a much wider spectral range than the pillar-diameter-induced perturbation. we also show that the mechanical quality factors for the non-whispering-gallery mechanical mode could be increased in the order of 4 magnitudes at a specific subsidence, and form a mechanical bound state in the continuum (BIC) which is induced by the symmetry breaking and reveals new mechanisms to confine radiation. A much broader BIC window width with higher mechanical quality factor could be achieved, which is of great importance in both fundamental research and scientific applications.
我们研究了几何形变对回音壁模式（WGM）微谐振器中不同模式的机械频率和品质因数的影响，这在实际制造中是不可避免的。本文首次对球体的下沉以及对称性更少、存在偏心、下沉和偏移等复杂形变的更一般情况进行了建模，与柱直径引起的微扰相比，这种情况能够在更宽的频谱范围内调节机械频率。我们还表明，在特定下沉情况下，非回音壁机械模式的机械品质因数可以提高约4个数量级，并形成由对称性破缺引起的连续谱中的机械束缚态（BIC），揭示了限制辐射的新机制。可以实现具有更高机械品质因数的更宽的BIC窗口宽度，这在基础研究和科学应用中都具有重要意义。
