Comparison of optical properties between ladder and lambda-type EIT medium with Er3+ ion concentration in Er3+:YAG crystal

The effect of Er³⁺ doped ion concentration on optical properties of two type three-level schemes in 35 nm Er³⁺:YAG (yttrium aluminum garnet) crystal is studied. It is found that intensity threshold of optical bistability and multistability can be changed by Er³⁺ doped ion concentration. Moreover, switching from optical multistability to optical bistability can be done differently by Er³⁺ concentration in two types of three-level schemes. The steady-state and transient behaviors of absorption, dispersion and group index of weak probe field in two schemes are also discussed. In this study, we will report an initial study on optical properties in Er³⁺:YAG crystal and propose a basis for selecting the suitable concentration to carry out experimental investigations in the future.