科研之友
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摘要
The interaction of a coherent light field with two adjacent two-sided cavities, each containing a semiconductor quantum dot which is charged by a single excess electron, is studied within S-matrix theory. Dissipation in the nonresonantly driven dots and intercavity losses are treated phenomenologically. Light transmission is studied as a function of the initial state of the quantum dots (QDs), light polarization, dissipative losses, as well as dissimilarities between the two QD cavities. The transmission spectrum consists of a superposition of resonances from the individual cavities and Fabry-Perot-like resonances associated with the double cavity. Faraday rotation and phase shifts caused by the nonresonantly driven trion transition allow nondestructive distinction between parallel "up," "down," and antiparallel spin orientation for the two excess electrons for identical cavities. With increasing asymmetry between the two cavities, the transmission spectrum reveals more and more the initial spin orientation of the individual electrons. Selection of the center frequency and duration of the incident laser pulse allows us to reveal preferentially either the relative spin orientation, needed as prerequisite for entanglement generation, or the orientation of individual spins. A quantitative estimate of the effects on the transmitted light arising from various physical sources of dissimilarities, as well as the effect from remote transitions, is given for typical system parameters.
- 出版日期2008-1
