Efficient and Tunable Photoinduced Honeycomb Lattice in an Atomic Ensemble

Artificial periodic structures (APS) with controllable optical properties are highly demanded in all-optical devices and circuits in communication networks. However, APS realized in solid materials are usually non-tunable and inherently possess immutable photonic bandgap. In this article, a novel honeycomb lattice in an atomic ensemble by utilizing the multi-beam interference method is reported. Unlike the honeycomb lattice formed in solid materials, the optical properties of this photoinduced honeycomb lattice, such as the absorption/dispersion coefficients and the photonic bandgap can be efficiently tuned by two-photon detuning and Rabi frequency, resulting in both amplitude- and phase- type honeycomb lattice. Based on the two-photon quantum-imaging method, the near-field diffraction of the honeycomb lattice is also investigated. It is found that the resolution of the diffraction pattern is tunable by simply adjusting the manner of the two detectors scanning across the imaging beams. In addition, the contrast of the pattern can be greatly enhanced by tuning the optical properties of the lattice. Such an optical honeycomb lattice with tunable properties could find applications in all-optical switching at the few photons level and paves the way for the generation and manipulation of optical topological insulators.