BaCa4Se7 compound, BaCa4Se7 nonlinear optical crystal, preparation method and application

The invention relates to a BaCa4Se7 compound, a BaCa4Se7 nonlinear optical crystal, a preparation method and application. The BaCa4Se7 compound is prepared by adopting a solid-phase reaction, and the BaCa4Se7 nonlinear optical crystal is grown by adopting a high-temperature melt spontaneous crystallization method, a flux growth method or a Bridgman method. In the growth of the BaCa4Se7 nonlinear optical crystal, the crystal is easy to grow and transparent and has no package and the advantages of higher growing speed, low cost, easy obtaining of a crystal in a larger size, and the like. The obtained BaCa4Se7 nonlinear optical crystal has the advantages of wider optical transparency range, larger hardness, good mechanical property, difficult cracking and deliquescence, easy processing and storage, and the like. The BaCa4Se7 nonlinear optical crystal can be used for preparing a nonlinear optical device.