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Plasmon-enhanced terahertz emission in self-assembled quantum dots by femtosecond pulses

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Carreño Sánchez, Fernando and Antón Revilla, Miguel Ángel and Melle Hernández, Sonia and Gómez Calderón, Óscar and Cabrera Granado, Eduardo and Cox, Joel and Singh, Mahi R. and Egatz-Gómez, Ana (2014) Plasmon-enhanced terahertz emission in self-assembled quantum dots by femtosecond pulses. Journal of Applied Physics, 115 (6). ISSN 0021-8979

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Official URL: http://dx.doi.org/10.1063/1.4863781




Abstract

A scheme for terahertz (THz) generation from intraband transition in a self-assembled quantum dot (QD) molecule coupled to a metallic nanoparticle (MNP) is analyzed. The QD structure is described as a three-level atom-like system using the density matrix formalism. The MNP with spherical geometry is considered in the quasistatic approximation. A femtosecond laser pulse creates a coherent superposition of two subbands in the quantum dots and produces localized surface plasmons in the nanoparticle which act back upon the QD molecule via dipole-dipole interaction. As a result, coherent THz radiation with a frequency corresponding to the interlevel spacing can be obtained, which is strongly modified by the presence of the MNP. The peak value of the terahertz signal is analyzed as a function of nanoparticle's size, the MNP to QD distance, and the area of the applied laser field. In addition, we theoretically demonstrate that the terahertz pulse generation can be effectively controlled by making use of a train of femtosecond laser pulses. We show that by a proper choice of the parameters characterizing the pulse train a huge enhancement of the terahertz signal is obtained.


Item Type:Article
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Copyright (2014) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, 2014, 115 (6) and may be found at http://scitation.aip.org/content/aip/journal/jap/115/6/10.1063/1.4863781

Uncontrolled Keywords:Quantum dots, Plasmons, Nanoparticles, Semiconductors, Coherent population transfer, Raman-Sscattering Optical pulses, Cascade-laser
Subjects:Sciences > Physics > Optics
Sciences > Physics > Particles
Sciences > Physics > Quantum theory
ID Code:30092
Deposited On:18 May 2015 12:04
Last Modified:25 May 2015 14:30

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