Stimulated Terahertz Emission from Intraexcitonic Transitions in Cu 2 O
2006; American Physical Society; Volume: 96; Issue: 1 Linguagem: Inglês
10.1103/physrevlett.96.017402
ISSN1092-0145
AutoresR. Huber, B. A. Schmid, Y. R. Shen, Daniel S. Chemla, Robert A. Kaindl,
Tópico(s)Strong Light-Matter Interactions
ResumoWe report the first observation of stimulated emission of terahertz radiation from internal transitions of excitons. The far-infrared electromagnetic response of Cu2O is monitored via broadband terahertz pulses after ultrafast resonant excitation of three-dimensional 3p excitons. Stimulated emission from the 3p to the energetically lower 2s bound level occurs at a photon energy of 6.6 meV, with a cross section of approximately 10(-14) cm2. Simultaneous excitation of both exciton levels, in turn, drives quantum beats, which lead to efficient terahertz emission sharply peaked at the difference frequency.
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