Expressions of “fast” and “slow” chameleon dressed states in Autler–Townes spectra of alkali-metal atoms

We have investigated the formation of laser-dressed states in HF components of sodium atoms and their manifestations in Autler–Townes spectra. An explicit procedure is proposed for constructing a specific Morris–Shore wave function basis, within which two-photon excitation schemes are reduced to sets of mutually orthogonal 3- and 2-level excitation sequences, and single uncoupled states. It has been demonstrated that the Morris–Shore basis states correspond to bright and dark states, along with chameleon states introduced in our recent work. Numerical simulations of the Autler–Townes spectra reveal that chameleon states can be further categorized as “fast” or “slow.” Our extended classification of dressed states enables more accurate reconstruction of excited state properties in optical methods for atomic media diagnostics.