The middle infrared (IR) 3–12 μm range is of great importance in many applications due to the transparency windows (3–5 μm and 8–12 μm sub-ranges) in the atmosphere. A variety of nonlinear materials have been developed for frequency conversion from near IR to 3–12 μm spectral ranges [
1–
3]. As pumping sources for frequency conversion 1.064 μm Nd:YAG and (0.7–1.1 μm) Ti:sapphire lasers are the most desirable. Nd:YAG lasers possess high power, good optical parameters, and have been widely distributed and used in mobile systems, which permits us to design a wide band of 3–12 μm sources of coherent radiation. In turn, frequency conversion of Ti:sapphire laser is also desirable for designing middle IR tunable femtosecond sources. However, most middle IR nonlinear crystals (CdGeAS
2, ZnGeP
2, AgGaSe
2, CdSe, etc.) are not transparent or have big loss, or can not be phase matchable at the near IR regions. AgGaS
2 can be used with the pumping source of 1.064 μm Nd:YAG lasers, but it has low thermal conductivity and low damage threshold, leading to a lack of high-energy AgGaS
2 frequency converter operating at 3–12 μm range.