Publication

Ultrafast phase-locked spectroscopy of excitons in quantum nanostructures

Benoît Marie Joseph Deveaud
2002
Journal Articles

Abstract

We have investigated the ultrafast coherent dynamics of exciton-polaritons and excitons in semiconductor quantum nanostructures, including InGaAs/AlGaAs multi quantum well Bragg structures and AlGaAs/GaAs crescent shaped quantum wire samples, by using a phase-locked spectroscopic technique. In the multi quantum well Bragg sample, a two-stage decay due to the superradiant exciton-polariton mode is clearly observed at the resonant condition. In the crescent shaped quantum wire sample, the highly sensitive coherent control measurement enables us to observe the dephasing characteristics and a very fast dephasing time T-2 of 200 to 300 Is with power dependence was observed.

Official source

https://infoscience.epfl.ch/entities/publication/f5b9abd3-8161-49e1-bfbc-5ea2e9a89ad4

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Benoît Marie Joseph Deveaud
2002
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/f5b9abd3-8161-49e1-bfbc-5ea2e9a89ad4

About this result

Related concepts (31)

Ultrafast laser spectroscopy

Ultrafast laser spectroscopy is a spectroscopic technique that uses ultrashort pulse lasers for the study of dynamics on extremely short time scales (attoseconds to nanoseconds). Different methods are used to examine the dynamics of charge carriers, atoms, and molecules. Many different procedures have been developed spanning different time scales and photon energy ranges; some common methods are listed below. Dynamics on the as to fs time scale are in general too fast to be measured electronically.

Quantum dot

Quantum dots (QDs) – also called semiconductor nanocrystals, are semiconductor particles a few nanometres in size, having optical and electronic properties that differ from those of larger particles as a result of quantum mechanics. They are a central topic in nanotechnology and materials science. When the quantum dots are illuminated by UV light, an electron in the quantum dot can be excited to a state of higher energy. In the case of a semiconducting quantum dot, this process corresponds to the transition of an electron from the valence band to the conductance band.

Quantum well

A quantum well is a potential well with only discrete energy values. The classic model used to demonstrate a quantum well is to confine particles, which were initially free to move in three dimensions, to two dimensions, by forcing them to occupy a planar region. The effects of quantum confinement take place when the quantum well thickness becomes comparable to the de Broglie wavelength of the carriers (generally electrons and holes), leading to energy levels called "energy subbands", i.e.

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Ultrafast phase-locked spectroscopy of excitons in quantum nanostructures

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