Asymmetric high-intensity diffraction via the vortex light in quantum dot molecules system

We propose an alternative scheme for implementing a two-dimensional (2D) asymmetric grating with high diffraction intensity in a five-level quantum dots molecules (QDMs) system, which is induced by the interdot tunneling and is driven by a 2D standing-wave field and a vortex optical field. In the presence of the vortex beam, diffracting a weak probe beam into higher-order directions could be achieved, where the diffraction direction could be switched among different quadrants by simply adjusting the orbital angular momentum. Furthermore, other parameters such as tunneling strength, probe detuning, beam waist and Rabi frequencies have a certain impact on diffraction intensity and diffraction direction. The scheme we present has the striking feature for effectively controlling the diffraction direction and greatly improving the diffraction efficiency in 2D space, which is beneficial to the potential applications in quantum information processing and design of optical devices.