Microcavities based on multimodal interference.
We describe intricate cavity mode structures, that are possible in waveguide devices with two or more guided modes. The main element is interference between the scattered fields of two modes at the facets, resulting in multipole or mode cancelations. Therefore, strong coupling between the modes, such as around zero group velocity points, is advantageous to obtain high quality factors. We discuss the mechanism in three different settings: a cylindrical structure with and without negative group velocity mode, and a surface plasmon device. A general semi-analytical expression for the cavity parameters describes the phenomenon, and it is validated with extensive numerical calculations.
Maes
Björn
B
Dept. of Physics, Center for Materials Science and Engineering, Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge 02139, Massachusetts, USA. bjorn.maes@ugent.be
Ibanescu
Mihai
M
Joannopoulos
John D
JD
Bienstman
Peter
P
Baets
Roel
R