Electromagnetically induced transparency (EIT) effect is normally originated from a quantum interference occurring in three-level atomic systems and it is one of the important research objects in quantum optics. The EIT effect can provide a narrowband transparency window within a wide absorption spectrum, which has promising applications in light storage, communications and computations in both classic and quantum ranges.
Very recently, a novel structure called moiré patterns has been proposed, which is a man-made two-dimensional (2D) twisted structure of two identical periodic structures overlapped in a twisted angle. However, the fabrication of the moiré patterns in the gaseous medium is still a challenge. Therefore, a new type of structure is in urgent demand to further prompt the development of EIT generated from man-made structures.
In a study published in Frontiers of Physics, a research team led by Prof. Dr. ZENG Jianhua from Xi'an Institute of Optics and Precision Mechanics (XIOPM) of the Chinese Academy of Sciences (CAS) proposed a novel approach for generating EIT by moiré optical lattices in a coherent atomic gas.
According to the researchers, their theoretical bases for the proposed approaches to generate the EIT effect are related to the three-level Λ-type coherent atomic ensemble, which is a feasible method that can be experimentally implemented by the current conditions of realistic physical systems.
In their numerical simulation, the plane wave expansion was adopted to solve the eigenvalue problem. Moreover, due to the spatial periodic features of the proposed structure, the periodic boundary condition was also applied based on the Bloch theory.
In conclusion, a novel approach for generating EIT by moiré lattice was proposed, and the simulation results indicated that the lattice depth, twisted angle, and strength contrast were all have great influences on the shapes and the band-gap structures of the resulting moiré lattice.
The performance make the proposed approach feasible because it can be realized by the current conditions of physical systems.
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