Parity-time-symmetric optical lattices in atomic configurations

In this chapter, we show how to theoretically design and experimentally construct exact parity-time (PT) symmetric optical lattices with gain and loss in atomic configurations. By making use of the advantages of light-induced atomic coherence in multi-level atomic systems, spatially extended gain and loss arrays with real-time reconfigurability and multiple-parameter tunability can be effectively obtained in hot atomic vapors. We have constructed periodically alternative gain-loss structures with two very different schemes based on spatially-arranged optical induction techniques. With the required symmetric/antisymmetric spatial distributions for the real/imaginary parts of the refraction index satisfied, PT-symmetric optical lattices can be achieved with easy controllability. The dynamic behaviors of light propagating inside the induced non-Hermitian optical lattices are investigated by measuring the relative phase difference between two adjacent gain and loss channels.