Semi-Classical Description of Rayleigh Light Scattering

This chapter delves into a semiclassical description of high-intensity Rayleigh scattering, employing the Heisenberg-Langevin operator equations. In this analysis, we treat the incident field as classical while considering the scatterer as quantum. Within resonant scattering, where the external field’s frequency matches the transition frequency of a two-level atom, we unveil an intriguing phenomenon in the response spectrum. Alongside the narrow Rayleigh scattering line, three new lines emerge. Among them, one aligns with the incident light’s frequency, while the other two exhibit frequency shifts corresponding to the Rabi frequency. This phenomenon is recognized as the Mollow triplet. We also explore the nonresonant scenario, where the most intense line aligns with the atom’s transition frequency, while the remaining two lines are significantly weaker. These two lines manifest in Raman scattering as background noise, often eclipsing the Raman effect and requiring careful consideration.