Beta-Cesium Cadmium Silicon Sulfide Compound, Beta-Cs2CdSi4S10 Nonlinear Optical Crystal and Preparation Methods and Applications Thereof

A method for preparing a β-Cs2CdSi4S10 infrared nonlinear optical crystal, which adopts a Bridgeman-Stockbarge method, comprising the following steps:

• a. Placing the β-Cs2CdSi4S10 compound prepared by a vacuum packaging method in a muffle furnace, heating the muffle furnace to 650° C. and maintaining the temperature for 100 hours to obtain a mixed melt;
• b. Obtaining seed crystals of β-Cs2CdSi4S10 by slowly cooling the mixed melt obtained in step a at a rate of 3° C./h to 300° C. and then rapidly cooling it at a rate of 5-15° C./h to room temperature;
• c. Placing the seed crystal prepared in step b at the bottom of a platinum crucible, and then placing the β-Cs2CdSi4S10 compound prepared in step a into the platinum crucible;
• sealing the platinum crucible and then placing it in a growth furnace;
• heating the growth furnace to 640-670° C. and maintaining the temperature for 100-200 hours;
• then lowering the platinum crucible at a rate of 1-10 mm/day while keeping the temperature of the growth furnace constant or cooling it at a rate of 2-3° C./h to 300° C.;
• quickly cooling it at a rate of 5-15° C./h to room temperature after finishing the growth;
• finally, opening the platinum crucible to obtain the desired β-Cs2CdSi4S10 infrared nonlinear optical crystal.

A method for preparing a β-Cs2CdSi4S10 infrared nonlinear optical crystal, which adopts a vacuum packaging method, comprising the following steps:

• Placing the β-Cs2CdSi4S10 compound prepared by a vacuum packaging method in a quartz tube;
• evacuating the quartz tube to a vacuum degree of 1×10−3 Pa;
• sealing the quartz tube at high temperature and placing it in a muffle furnace;
• heating the muffle furnace to 630-650° C. and maintaining the temperature for 100 hours, then cooling it at a rate of 3° C./h to 300° C. and then rapidly cooling it at a rate of 5-10° C./h to room temperature;
• finally, opening the quartz tube to obtain the desired β-Cs2CdSi4S10 infrared nonlinear optical crystal.