OPTICAL FREQUENCY MULTIPLICATION

An apparatus for generating laser radiation at a frequency multiplied as compared with a base frequency, has an optical resonator, in which input laser radiation circulates resonantly at the base frequency, and at least one conversion element through which the input laser radiation circulating in the optical resonator radiates, and which converts this radiation, at least in part, into output laser radiation at the multiplied frequency. At least one compensation element is provided, through which the input laser radiation circulating in the optical resonator also radiates, and which absorbs this radiation, in part, wherein the compensation element balances out a temperature-dependent variation of the optical path length of the input laser radiation in the conversion element, at least in part. Furthermore, a system generates laser radiation.