Hannover 2010 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 67: Photonics IV
Q 67.7: Vortrag
Freitag, 12. März 2010, 15:30–15:45, F 128
Optical bistability and all-optical switching in bottle
microresonators at very low powers via the Kerr effect — •Michael Pöllinger and Arno Rauschenbeutel — QUANTUM, Institut für Physik, Johannes Gutenberg-Universität Mainz, 55099 Mainz
We present experimental results on nonlinear, low-power photonics applications of a silica whispering-gallery-mode microresonator. In contrast to microspheres and microtoroidal resonators, where the light is typically guided in a narrow ring along the equator of the structure, the prolate shape of our bottle microresonator gives rise to an advantageous mode structure with two independent coupling points accessible for two nanofiber-couplers. This makes our resonator a real four-port device. Moreover, at a wavelength of 852 nm, the resonator yields an ultra-high intrinsic quality factor Q exceeding 108 and a mode volume around V = 1300 µm3. The resulting Q2/V-ratio is among the highest realized for optical microresonators. The shift of resonance frequency in units of the linewidth scales with this ratio. Therefore, despite the small nonlinear refractive index of silica we observe optical bistability and all-optical switching at thresholds of some 100 µW via the Kerr effect and of some tens of µW for the slower thermo-optical effect. Finally, the possibility of enhancing the Kerr nonlinearity by coating the resonator with thin polymer-films is discussed.
Financial support by the DFG, the ESF, and the Volkswagen Foundation is gratefully acknowledged.