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Motivation: telegraphic fluorescence (driven spontaneous emission) of single atoms

Example single V-systems: two upper levels 1 (fast spontaneous emission) and 2 (slow spontaneous emission), one lower level 0 driven by two lasers. Transition $ 0\to 2$ traps the system in 2 for a long time. Resonance fluorescence intensity $ I(t)$ therefore exhibits jumps: `telegraphic fluorescence' with random switching between bright and dark periods. Aim: calculate distribution of dark periods.

Length $ T_D$ of dark period can be simply calculated from the density matrix element $ \rho_{22}$

$\displaystyle T_D^{-1}$ $\displaystyle =$ $\displaystyle \dot{\rho}_{22}(t=0),\quad \rho_{22}=0,$ (138)

where the derivative is calculated from the underlying equation of motion (Master equation). However, the calculation of other, more complicated quantities related to the description of telegraphic fluorescence turns out to be technically complicated within the Master equation formalism. Example: `exclusive probability' $ P_0(t)$ that, after an emission at time $ t=0$, no other photon has been emitted in the time interval $ [0,t]$.


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Next: Unravelling and Decomposition into Up: Introduction Previous: Introduction   Contents   Index
Tobias Brandes 2004-02-18