Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 6: Photonic crystals I
HL 6.5: Vortrag
Montag, 25. Februar 2008, 10:30–10:45, EW 201
Coupling of Photonic Resonators with Liquid Crystals — •Karoline A. Piegdon1, Heiner Matthias2, Heinz-S. Kitzerow2, and Cedrik Meier1 — 1Experimental Physics, Group NanoPhox, University of Duisburg-Essen — 2Faculty of Science, Physical Chemistry, University of Paderborn
In order to achieve resonance between a photonic resonator with high quality factor and an emitter with narrow bandwidth, continuous tuning of the resonance frequency is desirable. However, in a semiconductor cavity, it is very difficult to alter the optical path length for this purpose. Matching the frequency of the emitter only by adjusting the device geometry is nearly impossible since even small fabrication imperfections affect the resonance frequency of the cavity considerably. Liquid crystals (LC) are promising candidates to make semiconductor devices tuneable since their refractive indices depend strongly on temperature and external fields.
Here, we report about GaAs microdisks (MD) with InAs quantum dots as built-in light emitters. The MD are embedded in the LC 5CB. The LC was aligned by surface treatment and an electric field. Subsequently, the temperature induced spectral shift of a cavity mode was monitored. The peak wavelength was shifted by 7.5 nm with increasing temperature at the nematic-isotropic phase transition. FDTD simulations and theoretical estimates are in agreement with this shift value. The mode shift was also monitored in situ while the LC was aligned in an electric field. In conclusion, a novel hybrid photonic device is presented that can be tuned by temperature and external fields.