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频率上转换现象发现于40年代，50年代初开始了稀土离子的上转换发光研究，随后由于夜视等军事目的的促进，上转换研究有了一段发展较快的时期．1971年首次观察到了上转换产生的受激发射，但由于上转换激光器效率低，必须在低于液氮温度下运转，当时这方面的研究还未引起人们的
The up-conversion phenomenon was discovered in the 1940s and early 1950s, and the upconversion luminescence study of rare earth ions began. After that, due to the promotion of military purposes such as night vision, the up-conversion study developed rapidly. The stimulated emission from the up-conversion was first observed in 1971, but due to the inefficiency of the up-conversion laser, it was necessary to operate at temperatures below liquid nitrogen temperatures, when research in this area had not caused the