Mode coupling and cavity-quantum-dot interactions in a fiber-coupled microdisk cavity
- Center for the Physics of Information, California Institute of Technology, Pasadena, California 91125 (United States)
- Department of Applied Physics, California Institute of Technology, Pasadena, California 91125 (United States)
A quantum master equation model for the interaction between a two-level system and whispering-gallery modes (WGMs) of a microdisk cavity is presented, with specific attention paid to current experiments involving a semiconductor quantum dot (QD) embedded in a fiber-coupled Al{sub x}Ga{sub 1-x}As microdisk cavity. In standard single mode cavity QED, three important rates characterize the system: the QD-cavity coupling rate g, the cavity decay rate {kappa}, and the QD dephasing rate {gamma}{sub (perpendicular)}. A more accurate model of the microdisk cavity includes two additional features. The first is a second cavity mode that can couple to the QD, which for an ideal microdisk corresponds to a traveling wave WGM propagating counter to the first WGM. The second feature is a coupling between these two traveling wave WGMs, at a rate {beta}, due to backscattering caused by surface roughness that is present in fabricated devices. We consider the transmitted and reflected signals from the cavity for different parameter regimes of {l_brace}g,{beta},{kappa},{gamma}{sub (perpendicular)}{r_brace}. A result of this analysis is that even in the presence of negligible roughness-induced backscattering, a strongly coupled QD mediates coupling between the traveling wave WGMs, resulting in an enhanced effective coherent coupling rate g={radical}(2)g{sub 0} corresponding to that of a standing wave WGM with an electric field maximum at the position of the QD. In addition, analysis of the second-order correlation function of the reflected signal from the cavity indicates that regions of strong photon antibunching or bunching may be present depending upon the strength of coupling of the QD to each of the cavity modes. Such intensity correlation information will likely be valuable in interpreting experimental measurements of a strongly coupled QD to a bimodal WGM cavity.
- OSTI ID:
- 20982190
- Journal Information:
- Physical Review. A, Vol. 75, Issue 2; Other Information: DOI: 10.1103/PhysRevA.75.023814; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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