Fig. 1. Robust and nonreciprocal adiabatic passage.

a Stimulated Raman adiabatic passage in a three-level system (left panel). With a counterintuitive electromagnetic pulse sequence that S(t) precedes P(t) with $\Delta t$ (shown in the right panel with the vertical coordinate for electric field $E$), the population in |1〉 can robustly transfer to |3〉 without transient population in |2〉. b A schematic for the transient acoustic adiabatic passages with three detuned cavities resonant at $f_A$, $f_B$ and $f_C$, respectively (left panel). In addition to the Gaussian-shaped envelops, the signs of the couplings ${\kappa }_{AB}\left(t\right)$ and ${\kappa }_{BC}\left(t\right)$ are periodically flipped to realize temporal quasi-phase mismatching between the waves in adjacent cavities (right panel). The sequential dynamic couplings bring a robust transfer from cavity A to cavity C and can enable our system to be a circulator or a unidirectional absorber for the transient waves, with the detailed results presented in the following sections.