Any of several devices that convert incident electromagnetic radiation of mixed frequencies to one or more discrete frequencies of highly amplified and coherent ultraviolet, visible, or infrared radiation. 激光器使偶然的混雜頻率的電磁輻射,變為一個或更多的高度強化和連續的紫外線、可見光或紅外線輻射的分離頻率儀器中的一種