| Date |
Do, 21.05.2015 - Do, 21.05.2015 |
| Time |
11.15 |
| Speaker |
Dr. Thilo Stöferle, IBM Research GmbH, Zurich Research Laboratory, Rüschlikon |
| Location |
Universität Bern, Institut für Angewandte Physik, Gebäude exakte Wissenschaften, Hörsaal B116, Sidlerstrasse 5, 3012 Bern |
| Program |
Integrated photonics is key for future data communication systems. A brief overview of the activities at IBM Research – Zurich will be given, with focus on our Quantum Photonics section, which investigates new microcavity structures and materials for enhanced light-matter interaction. In our experiments, we create exciton-polariton quasiparticles by exciting optically a microcavity filled with a ladder-type conjugated polymer in the strong coupling regime. At room temperature thermalization of these quasi-particles occurs while it is suppressed at low temperature because of a relaxation bottleneck. Above a certain excitation threshold with incoherent off-resonant picosecond laser pulses, we observe the emergence of non-equilibrium Bose-Einstein condensation in the lower polariton branch. This is evidenced by several distinct features such as a blue-shifted emission peak at zero in-plane momentum, accompanied by a nonlinear increase in the emission intensity and a sudden drop of the linewidth. Furthermore, the emission becomes polarized and the emission dynamics is drastically shortened. Spatially-resolved measurements with a Michelson interferometer show a macroscopic phase relation over almost the whole spot, and the fringe pattern exhibits non-flat phase fronts and fork-like dislocations, indicating a large number of vortices and excitations. Our approach demonstrates a radically simplified route to Bose- Einstein condensation physics at ambient conditions with easy-to-process non-crystalline materials. |
| Download |
 (75 KB) |
|
(75 KB) |
| Link |
www.iap.unibe.ch |
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