Patent ID: 7327773

Claim:
A short pulse laser device with mode-locking, comprising: a resonator containing a laser crystal as well as several mirrors which define a long resonator arm as well as a short resonator arm, one of said several mirrors being a pump beam in-coupling mirror, and another of said several mirrors being a laser beam out-coupler, and a multiple reflection telescope increasing the resonator length and associated with one of the long resonator arm and the short resonator arm, said multiple reflection telescope being constructed using mirrors in order to reflect a laser beam coupled into the space between them back and forth between the mirrors several times before the laser beam is out-coupled back into the remaining resonator, sequential eccentric reflection points on the mirrors being offset relative to one another, wherein the telescope has only one curved mirror and a plane mirror, the position of the plane mirror being substantially midway between a first imaginary curved mirror and a second imaginary curved mirror forming an imaginary multiple reflection arrangement, the one curved mirror of the telescope being located in the position of the first imaginary curved mirror and containing the reflection points of the second imaginary curved mirror.