Berlin 2018 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 1: Whispering Gallery Mode Resonators I

KFM 1.3: Talk

Monday, March 12, 2018, 10:30–10:50, EMH 025

Widely tunable polymer-based photonic devices — Tobias Siegle, Simon Woska, Stefan Schierle, Michael Remmel, Matthias Migeot, •Carolin Klusmann, and Heinz Kalt — Institute of Applied Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany

Whispering gallery mode (WGM) resonators have a wide range of applications such as optical sensors, lasers or filters and modulators. Using polymers as resonator material and exploiting the flexibility of elastomeric substrates enables a tunability that further enhances the functionality of photonic devices. In this contribution we demonstrate a fine, reversible and spectrally wide resonance tuning using a novel type of WGM resonators. Further we report on the realization of photonic molecules with tunable coupling. Resonance tuning is achieved using a split-disk geometry - two opposing half-disks structured with direct laser writing onto a elastomeric substrate. Calibrated straining of the substrate allows reversibly tuning the distance between the half-disks and hence the resonance wavelength. Laser emission from dye-doped split-disk resonators reveals a wide tunability of more than three times the free spectral range. Similarly, adjacent goblet-shaped resonators are structured on the elastomer using direct laser writing. Resolving the laser emission spectroscopically and spatially while reducing the coupling gap demonstrates the formation of photonic molecules. Variation of the gap width and hence the coupling strength results in tunable laser-mode intensities, in particular in super-mode formation and mode vanishing due to the Vernier effect.