title: Abnormal high-Q modes of coupled stadium-shaped microcavities.
abstract: It is well known that the strongly deformed microcavity with fully chaotic ray dynamics cannot support high-Q modes due to its fast chaotic diffusion to the critical line of refractive emission. Here, we investigate how the Q factor is modified when two chaotic cavities are coupled, and show that some modes, whose Q factor is about 10 times higher than that of the corresponding single cavity, can exist. These abnormal high-Q modes are the result of an optimal combination of coupling and cavity geometry. As an example, in the coupled stadium-shaped microcavities, the mode pattern extends over both cavities such that it follows a whispering-gallery-type mode at both ends, whereas a big coupling spot forms at the closest contact of the two microcavities. The pattern of such a "rounded bow tie" mode allows the mode to have a high-Q factor. This mode pattern minimizes the leakage of light at both ends of the microcavities as the pattern at both ends is similar to the whispering gallery mode.
authors.forename: Jung-Wan
authors.initials: JW
authors.lastname: Ryu
authors.forename: Soo-Young
authors.initials: SY
authors.lastname: Lee
authors.forename: Inbo
authors.initials: I
authors.lastname: Kim
authors.forename: Muhan
authors.initials: M
authors.lastname: Choi
authors.forename: Martina
authors.initials: M
authors.lastname: Hentschel
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Kim