A quantum formalism for a terahertz acoustic laser



Título del documento: A quantum formalism for a terahertz acoustic laser
Revista: Brazilian journal of physics
Base de datos: PERIÓDICA
Número de sistema: 000159051
ISSN: 0103-9733
Autors: 1

Institucions: 1Universidad de La Habana, Facultad de Física, La Habana. Cuba
2Universidade Federal Fluminense, Instituto de Física, Niteroi, Rio de Janeiro. Brasil
Any:
Període: Dic
Volum: 29
Número: 4
Paginació: 694-701
País: Brasil
Idioma: Inglés
Tipo de documento: Artículo
Enfoque: Analítico
Resumen en inglés The aim of this work is to improve the study of a phonon laser (saser) proposed by us several years ago[1]. This is a device capable to generate an intense coherent beam of acoustical phonons. Our acoustic laser consists in a double barrier heterostructure tailored such the energy difference between the ground and the first excited state in the well is close to the energy of the LO phonon. The electrons are directly injected into the excited level. Therefore they decay producing a high rate of LO phonons. These phonons are confined inside the well and decay into a pair of phonons[2]: LO ® + TA. The TA phonons escape the well in the [111] direction constituting an intense coherent beam. Recently were studied (and sometimes realized experimentally) several kinds of phonon lasers. Up to our knowledge our saser is the only that has a very short wavelength (smaller than 25 Å) and a very long range (greater than 1000 mm). Because of that, such beam could have applications to acoustic nanoscopy, acoustic nanolithography and phonoelectronics. In early articles[1, 3, 4, 5, 6] we get the kinetic equations for the averaged electron and phonon populations. Quantum fluctuations were not taken into account. The system Hamiltonian is H = He + Hph + He-ph + Hph-ph + He-e. To solve this Hamiltonian we expand their eigenfunctions in the basis of the eigenstates ½jn1n2n3ñ of the single particle part of it. We obtain a set of coupled equations for the expansion coefficients that can be solved with some approximations. The results are qualitatively similar to those obtained previously
Disciplines Física y astronomía
Paraules clau: Acústica,
Física de materia condensada,
Láser,
Fonones,
Formalismo cuántico,
Heteroestructuras,
Pozos cuánticos
Keyword: Physics and astronomy,
Acoustics,
Condensed matter physics,
LASER,
Phonons,
Quantum formalism,
Heterostructures,
Quantum wells
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