a Fabry-Perot resonator comprising a first optical reflector, a reflective diffraction grating, a first prism, and a second optical reflector,

wherein the diffraction grating and the first prism are located in an optical path between the first and second optical reflectors to direct light from the first optical reflector to the second optical resonator and vice versa, and

wherein the diffraction grating is positioned to direct light from the first optical reflector at a first location on the diffraction grating to the first prism and the first prism reflects the light back to a second location on the diffraction grating which directs the reflected light from the first prism to the second reflector which is oriented to reflect the light back to the diffraction grating to retrace an optical path from the first optical reflector to the second optical reflector via the diffraction grating and the first prism;

an optical saturable absorber unit located in the optical path between the first and second optical reflectors of the Fabry-Perot resonator;

a first optical gain medium located in the optical path between the first and second optical reflectors of the Fabry-Perot resonator, wherein the optical grain medium absorbs pump light at a pump wavelength to emit laser light at a laser wavelength different from the pump wavelength and produces an optical gain at the laser wavelength;

a first optical coupler located in the optical path between the first and second optical reflectors of the Fabry-Perot resonator to couple the pump light into the Fabry-Perot resonator to cause the optical gain medium to emit the laser light;

a second optical coupler located in the optical path between the first and second optical reflectors of the Fabry-Perot resonator to couple a portion of the laser light in the Fabry-Perot resonator out of the Fabry-Perot resonator as a laser output beam;

an optical amplifier placed in an optical path of the laser output beam to amplify power of the laser output beam;

an optical element to direct the laser output beam from the optical amplifier to the diffraction grating which directs the laser output beam along a first optical path; and

a second prism located in the first optical path to receive the laser output beam from the diffraction grating and operable in combination with the diffraction grating and the second optical reflector to direct the laser output beam, sequentially, from the second prism to the diffraction grating, from the diffraction grating to the second optical reflector, from the second optical reflector to the diffraction grating, from the diffraction grating to the second prism, from the second prism to the diffraction grating which further directs the laser output beam along a second optical path.