STOCHASTIC DYNAMICS OF A SINGLE IMPURITY MOLECULE FROM THE VIEWPOINT OF CONTINUOUS MEASUREMENT THEORY

Stochastic dynamics of a laser-driven four-level system serving as a m odel or a single guest chromophore molecule in an amorphous polymer ho st is studied. The dynamics of ''slow'' transitions (spectral jumps), accompanied by instantaneous changes in the fluorescence frequency, is simulated on the basis of continuous measurement theory. It is shown that there is an opportunity to control the statistics of ''bright'' a nd ''dark'' periods by using laser fields to drive molecules having di fferent tunneling rates for the ground and excited electronic stales. The effect of population cycling in a four-level system and related ef fects of local heating or cooling of the environment are discussed. [S 1950-2947(98)07002-4].