the invention concerning a pulsed laser is provided and includes an optical resonator being defined by at least two reflective elements , and the optical resonator defining a laser radiation beam path ; the laser further including a solid - state gain structure arranged so as to be in the beam path , the gain structure being operable to emit laser radiation by stimulated emission upon being pumped ; a housing operable of maintaining a vacuum or gas composition different from ambient gas within the housing , the housing defining an inside , which encloses at least a part of the optical resonator , so that at least a part of the beam path proceeds within the housing ; and a mode locker arranged so as to be in the beam path ; wherein the gas composition and / or gas pressure in the housing is controlled , and a gas mixture inside the housing has an optical nonlinearity which is lower than the nonlinearity of air .