Mainz 2017 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 32: Rydberg gasses I

A 32.1: Vortrag

Freitag, 10. März 2017, 11:00–11:15, HS 20

Rydberg blockade of excitons in Cu₂O — •Julian Heckötter¹, Marcel Freitag¹, Marc Aßmann¹, Tomasz Kazimierczuk², Dietmar Fröhlich¹, and Manfred Bayer¹ — ¹Experimentelle Physik 2, TU Dortmund, Dortmund, Germany — ²Institute of Experimental Physics, University of Warsaw, Warsaw, Poland

In this work we report on absorption measurements on Rydberg-Excitons [1] in Cu₂O with quantum numbers up to n=25. In Cu₂O, excitonic states with an odd angular momentum quantum number, such as P- and F-excitons, are dipole allowed. We study the interaction between P-envelope states of high principal quantum numbers. For non-degenerate states the concept of the Rydberg blockade mechanism [2] is introduced to explain the decrease in absorption for increasing laser powers. We find a scaling of the blockade efficiency as n¹⁰ in accordance with theory [1].

In recent two-color pump-probe experiments we used two narrow bandwidth dye lasers to investigate the interaction between degenerate states. For high pump powers, we find a decrease in absorption at the resonances of high n but also an enhancement in between. Here, the blockade efficiency shows a n⁸ scaling behaviour. In addition, for lower n states, the reduction of absorption is overlayed by an initial increase of the oscillator strengths.
[1] T. Kazimierczuk et al., Nature 514, (2014), p. 343
E. Urban et. al, Nature Physics 5, (2009)