TM²⁺ :Ⅱ-Ⅵ compounds have become the most potential materials used for infrared laser due to the advantage of wide tunable range, small excited state absorption, high absorption and emission cross section and high quantum efficiency at room temperature. The research progress of TM²⁺:Ⅱ-Ⅵ laser materials are retrospect in this paper. Both the applications of TM²⁺:Ⅱ-Ⅵ materials in laser devices and their preparation methods are reviewed, respectively. The laser performance of typical TM²⁺:Ⅱ-Ⅵ mid-infrared materials are summarized in detail, and the preparation methods for monocrystalline and polycrystalline of these materials are listed systematically. At last, the existing problems in this field are pointed out, and the development prospects and research trends are prospected.

Contents
1 Introduction
2 The structure and species of TM²⁺:Ⅱ-Ⅵ compounds
3 The laser properties of TM²⁺:Ⅱ-Ⅵ materials
3.1 Cr²⁺:ZnSe
3.2 Cr²⁺:ZnS
3.3 Fe²⁺:Ⅱ-Ⅵ materials
4 Preparation method of TM²⁺:Ⅱ-Ⅵ material
4.1 Preparation method of TM²⁺:Ⅱ-Ⅵ single crystal
4.2 Preparation method of TM²⁺:Ⅱ-Ⅵ poly-crystalline and ceramic materials
5 Conclusion