Regensburg 2019 – wissenschaftliches Programm
KFM 14.2: Poster
Mittwoch, 3. April 2019, 16:00–18:30, Poster C
Tunable Whispering-Gallery-Mode Resonators made from Liquid Crystal Elastomers — •Jannis Hessenauer, Carolin Klusmann, Simon Woska, Matthias Migeot, and Heinz Kalt — Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
Whispering-Gallery-Mode resonators are promising building blocks for the realization of photonic devices, such as optical filters, switches or modulators. For a proper performance of these devices, a high tunability of their components is required. To achieve this, we propose resonators made from Liquid Crystal Elastomers (LCEs) as a novel way to tune their resonance wavelength over a wide spectral range.
Their working principle is based on a thermally induced reversible phase transition of LCEs from a nematic to an isotropic phase, which changes the resonator dimension, and therefore the resonance wavelength. LCEs are aligned through a silanization process and LCE resonators are structured using Direct Laser Writing (DLW). To induce the phase transition and the resulting shape deformation, the LCE resonators are doped with an absorber dye. The latter allows heating individual resonators via laser illumination.
To demonstrate reversible tuning of the resonance wavelength, the temperature dependent mode spectra of LCE resonators are evaluated. Heating of the resonators leads to a partly reversible redshift of more than one Free Spectral Range (FSR). The underlying increase in resonator radius can also be used to enable tunable coupling of adjacent resonators in photonic molecules.