The invention relates to a laser (10), which at least comprises - an optical resonator (19) which has a transparent resonator layer (6), which is located between at least two mirrors (3, 11) and which is used to generate at least one resonance wavelength band Δλ at a defined resonator length I from a wavelength region defined by the design of the resonator (19), - a laser-active material (18) for generating the wavelength band from the wavelength spectrum, wherein the laser-active material (18) is located in at least a part of the resonator layer (6), - a pump source to excite the laser-active material (18), wherein the emitted wavelength band of the laser (10) is created at a defined pump performance from a superposition of the wavelength spectrum of the laser-active material (18) and the resonant modes of the resonator (19). The resonator (19) belongs to a thin layer actuator (14) and, as a layer stack together with the resonator (14), the thin layer actuator (14) forms an optical interference filter (27), wherein the thin layer actuator (14) has an actuator layer (13) between two electrodes (2, 5) which are linked to a voltage control unit (21) and are spaced from each other and are connected to the actuator layer (13), wherein the actuator layer (13) forms at least one part (4) of the resonator layer (6), which consists at least partially of elastic material which changes the resonator length I under voltage and wherein the elastic material is a reversibly deformable and dielectric elastomer.