Dynamically tunable three-color reflections immune to disorder in optical lattices with trapped cold <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Rb</mml:mi><mml:mprescripts/><mml:none/><mml:mn>87</mml:mn></mml:mmultiscripts></mml:math> atoms
Hong Yang, Tinggui Zhang, Yan Zhang, Jin‐Hui Wu
Abstract
We investigate a four-level tripod atomic sample trapped, respectively, in a one-dimensional order and disorder (atom number fluctuation) optical lattice to achieve the tunable and robust three-color reflections in the regimes of zero absorption. Based on electromagnetically induced transparency (EIT) and the periodic modulation of the atom number density, there are three reflection regions of high probe reflectivity in different frequency ranges, respectively. Such three-color reflections arise from the double-EIT atomic structure in the optical lattice and can also be observed by the suppression of the density of photonic states. One of them appears in the large detuning range, and the other two locate in two EIT windows, respectively, which are relatively narrow and can be dynamically manipulated flexibly. It is worth noting that such reflection scheme has strong robustness, i.e., it is immune to the atom number fluctuation in the disorder structure. Our results have potential applications in all-optical networks with respect to fabricating efficient devices (such as reflectors and diodes) for manipulating multicolor photon flows.