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Title: A study of optical properties of strongly coupled organic and inorganic semiconductor microcavities
Author: Samira , Ceccarelli
ISNI:       0000 0001 3548 092X
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2007
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In this thesis, an investigation into the optical properties of strongly-coupled inorganic and organic semiconductor microcavities is presented. An analysis ofthe polarisation properties ofthe signal emitted from a GaAs microcavity with InGaAs quantum wells for resonant excitation with one continuous wave laser beam is reported. Polarisation properties of the signal are discussed with respect to the power and linear polarisation of the excitation beam. Near-field spatial images of the signal are also presented. Results from theoretical numerical models are shown to agree with experimental results. Polarisation and spatial emission of the signal have also been studied for resonant excitation ofthe cavity with two independent laser beams. This led to the observation of a polariton state at nil wavevector and at the same energy of that ofthe OPO idlers. New scattering processes to explain this polariton state formation are presented. A variety of strongly-coupled organic semiconductor microcavities has been fabricated and characterised. Strong coupling is reported for cavities containing J-aggregates of a cyanine dye absorbing at near-infrared wavelengths. The result is a step towards the fabrication of hybrid structures containing organic and arsenide-based semiconductors. Here, evidence of a 'hybrid' organic-inorganic polariton state is reported for a cavity containing organic (molecular dye ZnTPP) and inorganic (perovskites) materials. The relative population of the polariton branches in strongly-coupled cavities containing J-aggregates of a cyanine dye have been investigated as a function of Rabi-splitting energy. Experimentally measured photoluminescence emission has been compared with a full quantum-mechanical model. Here, indirect experimental evidence of scattering of upper branch polariton states to the exciton reservoir is presented. This is shown to be more efficient when the energy separation between the polariton state and the uncoupled exciton is in resonance with the molecular vibrational modes of the organic material.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available