Dresden 2020 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 7: Whispering-Gallery-Mode Resonators

KFM 7.1: Talk

Tuesday, March 17, 2020, 14:00–14:20, TOE 317

Super-directional light emission and emission reversal from micro cavity arrays — Jakob Kreismann, Jaewon Kim, Martí Bosch, Matthias Hein, Stefan Sinzinger, and •Martina Hentschel — Institute for Micro- und Nanotechnologies, Technische Universität Ilmenau, Germany

Optical microdisk cavities with certain asymmetric shapes are known to possess uni-directional far-field emission properties. Here, we investigate arrays of these dielectric microresonators with respect to their emission properties resulting from the coherent behaviour of the coupled constituents. This approach is inspired by electronic mesoscopic physics where the additional interference effects are known to enhance the properties of the individual system. As an example we study the linear arrangement of nominally identical Limaçon-shaped cavities and confirm the increase of directionally emitted light. We find its angular spread to diminish from 20 degrees for the single cavity to about 3 degrees for a linear array of 10 Limaçon resonators, in fair agreement with a simple array model. Moreover, varying the inter-cavity distance we observe windows where the emission directionality is further enhanced (super-directionality), as well as windows with a reversal of the emission direction, another effect that may be interesting for applications like optical sensing or interconnects. We introduce a generalized array factor model that takes the coupling into account.