# Time-domain grating with a periodically driven qutrit

## TL;DR

This paper demonstrates the experimental realization of a time-domain grating using a superconducting qutrit, revealing novel diffraction effects and phase relationships in a three-level quantum system under periodic modulation.

## Contribution

It introduces the first experimental implementation of time-domain gratings in a three-level quantum system and analyzes the associated interference and diffraction phenomena.

## Key findings

- Modulated Autler-Townes and diffraction effects observed.
- Diffraction fringes linked to three-level phase, not just two-level.
- Fringe widths are independent of control-field power.

## Abstract

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. Here 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 however 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 multi-level systems and may find promising applications in fast all-microwave switches and quantum-gate operations in the strong-driving regime.