二十年前的上个月(指1958年7月),汤斯和肖洛申请了激光的专利,此时正值汤斯末次申请微波激射器专利之后六个月.下文是汤斯根据自己在美国科学促进协会一次会议上的特邀讲演而改写扩充的. Last month, twenty years ago, in July 1958, Towns and Lowau filed a patent for the laser at exactly six months after the last application of the hammers patent. His own speech at a meeting of the American Association for the Advancement of Science to rewrite the expansion.