Three-color reflections in one-dimensional ordered and disordered atomic lattices with trapped N-type cold atoms

Investigating and controlling light propagation in one-dimensional (1D) ordered and disordered atomic lattices is critical both fundamentally and for applications. In this study, cold atoms are trapped in 1D optical lattice and driven to the four-level N configuration. In each period, the atoms exhibit a Gaussian density distribution with the average atomic density N0 (1 + increment k). When the random number increment k = 0 (the atomic density Nk(z)) corresponding to an ordered 1D atomic lattice, there are three reflection regions of high reflectivity located in two EIT windows and one large detuning range. However, the atomic density may increase (Nk+ (z) with increment k > 0) or decrease (Nk-(z) with increment k < 0) owing to the imperfect manufacturing process or random distribution of atoms corresponding to a disordered atomic lattice. The results show that the width and height of reflections can be raised (reduced) by the increased (decreased) ratio of Nk+ (z)/Nk(z) (Nk- (z)/Nk(z)) with the random distribution of lattice cells with Nk+(z) (Nk-(z)). When a cluster of disordered lattice cells with Nk+ (z) and Nk- (z) is located at the front or tail of the atomic lattice, reflection symmetry can be broken. However, the symmetry and robustness can be well preserved with the random fluctuation of the average atomic density in each lattice cell.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement