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Laboratoire Pierre Aigrain

Accueil du site > Séminaires > 2008 > Seminar - 02/18/2008

Séminaire du 18/02/2008

Emission and detection of polaritons

CARLO SIRTORI (Matériaux et Phénomènes Quantiques, Université Paris Diderot)

Intersubband polaritons have been recently observed in reflectance measurements [1]. Nowadays a considerable effort is devoted to the conception and realisation of devices operating in the strong coupling regime. In this context, the vacuum Rabi splitting has been observed in intersubband photodetectors [2], and electrically injected polariton emission has been realised in a cavity organic LED [3]. In this seminar I will describe our results on the observation of polariton emission and detection in a semiconductor intersubband device. The latter is a GaAs/Al0.45Ga0.55As quantum cascade structure, emitting at 7.6µm, embedded in a planar microcavity [4]. The light confinement takes place between an Al0.95Ga0.05As layer and a metal contact, which also assures the electrical injection. Circular mesas are etched to define the region where the current is flowing. The main motivation of this work is to create new light sources operating in the strong coupling regime, such as polariton lasers and emitter with enhanced spontaneous emission rate. In conclusion I will present some idea, in the THz range, on how to achieve the ultra-strong coupling regime. In this wavelength range the vacuum Rabi splitting is comparable to the photon energy coupled to the system [5].

  1. D. Dini et al., Phys. Rev. Lett. 90, 116401 (2003).
  2. L. Sapienza et al., Appl. Phys. Lett. 90, 201101 (2007).
  3. J.R.Tischler et al., PRL 95, 036401 (2005).
  4. R. Colombelli et al., Semicond. Sci. Technol. 20, 985 (2005).
  5. C. Ciuti et al., Phys. Rev. B 72, 115303 (2005).