Time-Domain Grating with a Periodically Driven Qutrit

Physical systems in the time domain may exhibit analogous phenomena in real space, such
as time crystals, time-domain Fresnel lenses, and modulational interference in a qubit. We report
the experimental realization of time-domain grating using a superconducting qutrit in periodically
modulated probe and control fields via two schemes: simultaneous modulation and complementary
modulation. Both experimental and numerical results exhibit modulated Autler-Townes (AT) and
modulation-induced diffraction (MID) effects. Theoretical results also confirm that the peak positions
of the interference fringes of AT and MID effects are determined by the usual two-level relative
phases, while the observed diffraction fringes, appearing only in the complementary modulation,
are related to the three-level relative phase. Further analysis indicates that such a single-atom
time-domain diffraction originates from the correlation effect between the two time-domain
gratings. Moreover, we find that the widths of the diffraction fringes are independent of the
control-field power. Our results shed light on the experimental exploration of quantum
coherence for modulated multilevel systems and may find promising applications in fast
all-microwave switches and quantum-gate operations in the strong-driving regime.