A pulsed solid-state thin-disk laser comprises an optical resonator and a
solid-state laser gain medium placed inside the optical resonator. The
laser gain medium is in the shape of a thin plate or layer with two end
faces, the extension of the end faces being greater than a thickness of
said plate or layer measured in a direction perpendicular to one of the
end faces. One of the end faces comprises a cooling surface, via which the
laser gain medium is cooled. A pumping source is provided for exciting the
laser gain medium to emit electromagnetic radiation. The thin-disk laser
further comprises means for passive mode locking placed inside the optical
resonator. The mode-locking means are preferably a semiconductor saturable
absorber mirror (SESAM). The laser offers a high average power, a good
beam quality, short pulses and a high efficiency. Problems such as thermal
lensing, Q-switching instabilities and damages of the mode-locking means
are avoided. Moreover, the output power of the laser is scalable, i.e.,
may be increased without increasing the above-mentioned problems.