title: Mode-coupling analysis of three-dimensional microdisk resonators by the finite-difference time-domain technique.
abstract: Quality factor enhancement due to mode coupling is observed in a three-dimensional microdisk resonator. The microdisk, which is vertically sandwiched between air and a substrate, with a radius of 1 microm, a thickness of 0.2 microm, and a refractive index of 3.4, is considered in a finite-difference time-domain (FDTD) numerical simulation. The mode quality factor of the fundamental mode HE71 decreases with an increase of the refractive index of the substrate, n(sub), from 2.0 to 3.17. However, the mode quality factor of the first-order mode HE72 reaches a peak value at n(sub) = 2.7 because of the mode coupling between the fundamental and the first-order modes. The variation of mode field distributions due to the mode coupling is also observed. This mechanism may be used to realize high-quality-factor modes in microdisks with high-refractive-index substrates.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China. xsluo@mail.semi.ac.cn
authors.forename: Xian-Shu
authors.initials: XS
authors.lastname: Luo
authors.forename: Yong-Zhen
authors.initials: YZ
authors.lastname: Huang
authors.forename: Qin
authors.initials: Q
authors.lastname: Chen