Tunable optically-induced transmission grating via interacting dark resonances of microwave-driven Rydberg atoms

This study theoretically investigates a two-dimensional (2D), microwave-controlled hybrid amplitude-phase grating formed in a rubidium Rydberg atomic ensemble. In the proposed system, spatial modulation of the external fields induces a position-dependent atomic coherence, which in turn produces a spatial modulation of the susceptibility and refractive index. Consequently, a reconfigurable optical grating is formed, whose period and modulation depth can be controlled through the parameters of the applied fields. In particular, the microwave (MW) field provides an additional control mechanism for tailoring the Fraunhofer diffraction pattern by modifying both the amplitude and phase of the probe transmission function, thereby redistributing optical energy between the zeroth and higher diffraction orders. The effects of probe-field detuning, MW and coupling-field strength, propagation length, and Rydberg–Rydberg interactions on the diffraction characteristics are theoretically examined. The findings establish microwave-controlled Rydberg atomic gratings as a promising platform for reconfigurable spatial light modulation and potential applications in optical signal processing and microwave–optical communication.