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Asymmetric two-dimensional electromagnetically induced grating controlled by a vortex field

A new theoretical scheme for two-dimensional (2D) electromagnetically induced grating (EIG) is proposed in a three-level Ξ-type atomic system. The system is driven by a weak probe field and two position-dependent coupling fields—a 2D standing-wave field and a vortex field. Due to lopsided spatial modulation of the vortex Laguerre–Gaussian field, the weak probe light could be diffracted into different domains and asymmetric 2D EIG is formed. The result shows that the diffraction patterns and efficiency could be effectively modulated by the azimuthal parameter of the vortex field. Also, the system parameters such as the probe field detuning, the intensity of the vortex field, and the interaction length could be used to regulate the diffraction properties of the 2D EIG effectively. The scheme of asymmetric 2D EIG may have some potential application in all-optical information processing and the design of quantum devices.