title: The combination of high Q factor and chirality in twin cavities and microcavity chain.
abstract: Chirality in microcavities has recently shown its bright future in optical sensing and microsized coherent light sources. The key parameters for such applications are the high quality (Q) factor and large chirality. However, the previous reported chiral resonances are either low Q modes or require very special cavity designs. Here we demonstrate a novel, robust, and general mechanism to obtain the chirality in circular cavity. By placing a circular cavity and a spiral cavity in proximity, we show that ultra-high Q factor, large chirality, and unidirectional output can be obtained simultaneously. The highest Q factors of the non-orthogonal mode pairs are almost the same as the ones in circular cavity. And the co-propagating directions of the non-orthogonal mode pairs can be reversed by tuning the mode coupling. This new mechanism for the combination of high Q factor and large chirality is found to be very robust to cavity size, refractive index, and the shape deformation, showing very nice fabrication tolerance. And it can be further extended to microcavity chain and microcavity plane. We believe that our research will shed light on the practical applications of chirality and microcavities.
authors.affiliation: 1] Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China [2] State Key Laboratory on Tunable Laser Technology, Harbin Institute of Technology, Harbin, China.
authors.forename: Qinghai
authors.initials: Q
authors.lastname: Song
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Zhai
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Gu
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Kaiyang
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Material Science and Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Shang
authors.initials: S
authors.lastname: Sun
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Department of Electrical and Information Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Material Science and Engineering, Harbin Institute of Technology, Shenzhen, China.
authors.forename: Shumin
authors.initials: S
authors.lastname: Xiao