Chirped stimulated adiabatic passage with nonzero two-photon detuning

We develop a theory of stimulated Raman adiabatic passage (STIRAP), and fractional STIRAP (FSTIRAP) using frequency-chirped pulses. In both configurations, we find that pulse chirping faciliates higher contrast, a broader range of parameters for adiabaticity, and enhanced spectral selectivity. Additionally, we demonstrate that the pulse chirping allows for the relaxation of the condition of two-photon resonance necessary for adiabatic passage in STIRAP and FSTIRAP. Adiabatic passage to a predetermined state between two nearly degenerate final states, while unachievable in conventional STIRAP, is achived in chirped STIRAP by setting the condition |α|=|δ|/(t_p−t_s). This condition is accessible over a broad range of values for the two-photon detuning, δ, the chirp rate, α, and the pulse decay (tp-ts). In chirped FSTIRAP, chirping of the pump and Stokes pulses permits a complete compensation of the two-photon detuning that results in a selective maximum coherence of the initial and the target state with higher spectral resolution than in conventional F-STIRAP.

These proposed schemes will broaden the scope of quantum control methods and contribute to advancements in the fields of quantum imaging, sensing, and metrology.