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Q: Fachverband Quantenoptik und Photonik

Q 28: Quanteninformation: Photonen III

Q 28.5: Vortrag

Dienstag, 3. März 2009, 17:30–17:45, VMP 6 HS-D

Amplification of a Laser Beam by a Single Molecule — •Jaesuk Hwang, Martin Pototschnig, Gert Zumofen, Robert Lettow, Alois Renn, Stephan Götzinger, and Vahid Sandoghdar — Laboratory of Physical Chemistry and optETH, ETH Zurich, CH-8093 Zurich, Switzerland

In a recent work, we showed that we can strongly couple a laser beam to a single emitter, achieving more than 10% extinction in transmission [1]. We have also shown theoretically that it is possible to reflect light with 100% efficiency from a two-level system [2]. In this presentation, we report on the amplification of a laser beam by a single molecule in free space. In order to populate the upper state of the molecule, a short pump pulse excites it to the first vibrational level of the electronic excited state. This state quickly relaxes to the vibrational ground state of the electronic excited state with 10 ns lifetime. During this time and before the next pulse arrives, a weak probe laser beam interacts with the inverted molecule. We observed that a starting 7 % extinction of the probe beam is transformed into a 0.6% amplification in the presence of the pumping beam [3]. We will present a simple theoretical model that yields a very good agreement with our experimental data. [1] G. Wrigge et. al. Nature Physics 4, 60-66 (2008). [2] G. Zumofen et. al. Phys. Rev. Lett. 101, 180404 (2008). [3] J. Hwang et. al. in preparation.