“…One of the most important aspects of these properties is the modification of the absorption, dispersion, and nonlinearity of the system. Due to interaction of optical fields with nonlinear media, many interesting phenomena such as electromagnetically induced transparency [2,3], lasing without inversion (LWI) [4], high refractive index without absorption [5,6], four-wave mixing [7], optical solitons [8], optical bistability [9,10] and so on [11,12] have been investigated. Moreover, experimental evolution of above nonlinear optical phenomena has been reported and discussed.…”