Quantum jumps, atomic shelving and Monte Carlo fluorescence spectra

Abstract

We study the resonance fluorescence dynamics of a driven three-level atom in a “V”-configuration in which one transition is to a strongly fluorescing level and the other transition is to a metastable shelving state. This is the configuration in which quantum jumps, periods of bright fluorescence randomly interrupted by periods of darkness, have been studied experimentally using single three-level trapped ions. We use a Monte Carlo wavefunction simulation method to describe the evolution of single quantum systems. We concentrate on mean values for populations and intensities and also correlation functions for sequential detection of decay photons. For a single ensemble member the population of the state |;1〉 undergoes rapid oscillations which are interrupted by the detection of a photon. This resets the system in the ground state |;0〉. Very infrequently the oscillations die out as the system evolves into the metastable level |;2〉; this is the period of darkness which is terminated (in direct detection) by a quantum jump into the ground state. The ensemble averaged population shares features of the second order correlation function g (2) which we calculate using a recently-developed Monte-Carlo wave function method. We present results for the first and second order correlation functions and the spectra.