The invention relates to a light source, comprising an optical resonator (1) and an optical medium (2) arranged therein that can be excited so as to emit light, wherein the optical medium (2) comprises at least one two-level system, in particular a two-level system that is not population-inverted, having an at least metastable lower state, and the optical length of the resonator (1) comprising at least one curved mirror (1) is selected such that the free spectral bandwidth of the resonator is equal to or greater than the absorption bandwidth and/or fluorescence bandwidth of the optical medium (2) and only a single longitudinal mode and a plurality of transversal modes of the resonator (1) are arranged within the fluorescence bandwidth. The invention further relates to a method for producing light by means of an optical resonator (1) and an optical medium (2) arranged therein that can be excited so as to emit light, wherein at least one two-level system, in particular a two-level system that is not population-inverted, having an at least metastable lower state is selected as the optical medium (2), and the optical length of the resonator (1) comprising at least one curved mirror (1) is set in such a way that the free spectral bandwidth of the resonator is greater than the absorption bandwidth and/or fluorescence bandwidth of the optical medium (2) and only a single longitudinal mode (3) and a plurality of transversal modes (4) of the resonator (1) within the fluorescence bandwidth of the optical medium (2) are produced by means of excitation.