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Resonance fluorescence and superfluorescence of intersubband transitions

Resonance fluorescence and superfluorescence of intersubband transitions
Resonance fluorescence and superfluorescence of intersubband transitions
Intersubband transitions are unbound electronic transitions of doped quantum wells, semiconductors heterostructures with a planar symmetry. I theoretically studied the fluorescence of a strongly pumped intersubband transition, finding that the many electron nature of such a system leads to a modification of the usual Mollow triplet. In particular, the intensity of the central peak in the fluorescence spectrum becomes a function of the electron coherence, allowing access to the coherence time of a quasi two-dimensional electron gas through a fluorescence intensity measurement. Moreover, while transitions between the two states of the ac Stark-split doublet are forbidden in centrosymmetric systems, and thus almost impossible to observe in experiments performed with atoms they become allowed in asymmetric quantum wells, in which the wave function symmetry can be broken. I developed a many-body theory describing also this intradoublet emission, showing that by using doped asymmetry, the emission can be orders of magnitude higher than in previously studied systems. This opens the way to the realization of monolithic and tunable terahertz emitters since the Rabi frequency at which this emission occurs lies in the terahertz range and can be tuned by the pump power. Finally, I have investigated if superfluorescence can occur in intersubband transitions. In order to do so I used a general quantum master equation that includes dephasing and nonradiative emission to model the many-body system in solid state. Performing a second-order approximation allowed to obtain a closed system of equations that were studied analytically and numerically, verifying that in the regimes characteristic of intersubband transitions cooperative effects leading to powerful bursts of light could be observed experimentally.
University of Southampton
Shammah, Nathan
cefd9591-cc9b-4d59-abf4-1b1f62fc4300
Shammah, Nathan
cefd9591-cc9b-4d59-abf4-1b1f62fc4300
De Liberato, Simone
5942e45f-3115-4027-8653-a82667ed8473

Shammah, Nathan (2016) Resonance fluorescence and superfluorescence of intersubband transitions. University of Southampton, Physical Sciences and Engineering, Doctoral Thesis, 137pp.

Record type: Thesis (Doctoral)

Abstract

Intersubband transitions are unbound electronic transitions of doped quantum wells, semiconductors heterostructures with a planar symmetry. I theoretically studied the fluorescence of a strongly pumped intersubband transition, finding that the many electron nature of such a system leads to a modification of the usual Mollow triplet. In particular, the intensity of the central peak in the fluorescence spectrum becomes a function of the electron coherence, allowing access to the coherence time of a quasi two-dimensional electron gas through a fluorescence intensity measurement. Moreover, while transitions between the two states of the ac Stark-split doublet are forbidden in centrosymmetric systems, and thus almost impossible to observe in experiments performed with atoms they become allowed in asymmetric quantum wells, in which the wave function symmetry can be broken. I developed a many-body theory describing also this intradoublet emission, showing that by using doped asymmetry, the emission can be orders of magnitude higher than in previously studied systems. This opens the way to the realization of monolithic and tunable terahertz emitters since the Rabi frequency at which this emission occurs lies in the terahertz range and can be tuned by the pump power. Finally, I have investigated if superfluorescence can occur in intersubband transitions. In order to do so I used a general quantum master equation that includes dephasing and nonradiative emission to model the many-body system in solid state. Performing a second-order approximation allowed to obtain a closed system of equations that were studied analytically and numerically, verifying that in the regimes characteristic of intersubband transitions cooperative effects leading to powerful bursts of light could be observed experimentally.

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More information

Published date: July 2016
Organisations: University of Southampton, Physics & Astronomy, Quantum, Light & Matter Group

Identifiers

Local EPrints ID: 405495
URI: http://eprints.soton.ac.uk/id/eprint/405495
PURE UUID: e6faa854-1dbb-4b15-b7a2-750798b85f69
ORCID for Simone De Liberato: ORCID iD orcid.org/0000-0002-4851-2633

Catalogue record

Date deposited: 18 Feb 2017 00:23
Last modified: 24 May 2019 00:31

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