Theory of bandwidth induced asymmetry reversal in optical double resonances

Abstract

The authors examine the theory of optical double resonance using two lasers whose finite linewidths are produced by the process of phase-diffusion. Their lineshapes, which are nonLorentzian, are characterised by a bandwidth B and a cut off C. The authors are concerned with obtaining an analytic theory; they achieve this by assuming the ratio B/C to be small and work to first order in B/C (although the method can be extended to higher order in B/C). They obtain analytic expressions for the optical double resonance spectrum and discuss the results of recent experiments by Hogan et al. (1978) and Nitz et al. (1981) in which it was found that the asymmetry of the peaks in the optical double resonance spectrum changed with detuning. It is found that a qualitative understanding can be achieved but that a full quantitative comparison is not yet possible.