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arXiv · 2512.21740

Properties of a Three-Level $\Lambda$-Type Atom Driven by Coherent and Stochastic Fields

Sajad Ahmadi·Mohsen Akbari·Shahpoor Saeidian·Ali Motazedifard
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Abstract

We present a theoretical investigation of a three-level $\Lambda$-type atom driven by a strong coherent laser and a weak stochastic field exhibiting amplitude and phase fluctuations. The stochastic field is modeled as a complex Gaussian-Markovian random process with finite bandwidth to describe realistic laser noise. Using the Born-Markov and rotating-wave approximations, we derive a Lindblad-form master equation that incorporates spontaneous emission and noise-induced terms, and we solve for the steady-state regime. We examine level populations in both the bare and dressed bases and compute the incoherent resonance-fluorescence spectrum. Our analysis shows that the stochastic drive is not merely a source of decoherence but a versatile control parameter. By detuning the stochastic-field central frequency relative to the coherent drive (especially for narrow bandwidths), we observe pronounced changes in emission characteristics, including selective enhancement or suppression, and reshaping of the multi-peaked fluorescence spectrum when the detuning matches the generalized Rabi frequency. Numerical results reveal nontrivial steady-state modifications distinct from purely coherent driving, enabling precise control of populations and suggesting applications in quantum control, quantum technologies, spectroscopy, and noise-assisted manipulation of atomic systems.

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Sajad Ahmadi, Mohsen Akbari, Shahpoor Saeidian, Ali Motazedifard. 2025-12-25. Properties of a Three-Level $\Lambda$-Type Atom Driven by Coherent and Stochastic Fields. https://arxiv.org/abs/2512.21740

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