Correlated intensity fluctuations in a double resonance experiment

Bongjune Kim, Byoung‐Uk Sohn, Woojin Shin +2 more

We have demonstrated anticorrelated light switching between multiphoton transition channels in a nonresonant double-Λ system. Two-color probe transitions, using rubidium D1 (795 nm) and D2 (780 nm), were included in our double-Λ system. In anticorrelated light switching, one of two probe transitions is selected as transparent while the other is selected as opaque. In this configuration, we observed completely different behavior from that seen in a resonant double-Λ system, in which both probe transmissions are transparent or opaque simultaneously. Furthermore, we observed a noise correlation between two-color probe transmissions when the phase fluctuation of the two probe lasers was converted to the intensity fluctuation. The relative phase fluctuation between the two probe lasers induced an anticorrelation between the intensity noises of two probe lasers in a nonresonant double-Λ system, while a correlation was induced in a resonant double-Λ system. The intensity fluctuation (correlated or anticorrelated) was easily controlled by detuning the double-Λ system. The noise anticorrelation effect is clearly interpreted as arising from the anticorrelated light switching in a nonresonant double-Λ system. This system can be used for noise control as well as optical switching between incoherent two-color laser lights.

M. Wiegand

S. V. Lawande, Ravinder Rupchand Puri, Richard D’Souza

A formalism is presented to treat the effects of finite-bandwidth excitations on the fluorescent spectra and second-order intensity-correlation functions in optical double resonance. It is assumed that the bandwidth arises from the phase and/or amplitude fluctuations in the fields driving a three-level atom. Under the conditions that one or both these fields are intense, secular approximation and the theory of multiplicative stochastic processes are invoked to derive a Markovian master equation for the atomic-density operator averaged over both phase and amplitude ensembles. The quantum regression theorem is used to derive analytical expressions for the fluorescent spectra and the second-order intensity-correlation functions.

Georg M. Meyer, G. S. Agarwal, Hu Huang +1 more

W. Martienssen, Eberhard A. Spiller

A quasithermal, quasmonochromatic lamp is described which serves as a highly degenerate light source with adjustable coherence time between 10−5 sec and 1 sec. This lamp is used for several demonstration experiments concerning the relations between coherence and fluctuations: The intensity interferometer of Hanbury Brown and Twiss is applied to measure the correlations between intensity fluctuations. The double slit experiment of Young serves to stress the role of fluctuations for classical interferometry. Interference patterns from two independent quasithermal lamps are presented.

M. S. Kim, P. L. Knight, K. Wódkiewicz