Patent ID: 7778306

Claim:
A laser system comprising: a laser source emitting a laser beam; an articulated arm comprising an optical arrangement for guiding the laser beam from the laser source along an optical path within the articulated arm to a target location; wherein the articulated arm comprises at least one arm section moveable in an articulated way and further comprises a hand piece; wherein the laser source has a plane in which plane a beam profile of the laser beam at least approximately does not change when pumping conditions of the laser source are varied; wherein the optical arrangement is adapted to image the plane where said beam profile of the laser beam at least approximately does not change onto the target location; wherein within the optical path at least one crossing area of the laser beam is provided; wherein the optical arrangement comprises at least one optical cell arranged in said arm section, wherein said optical cell comprises an input window that is a convergent lens and an output window that is a convergent lens for passing the laser beam therethrough; wherein the at least one crossing area is positioned within said optical cell between the input window and the output window such that the input window focuses the laser beam on the crossing area and a cross-section of the laser beam widens from the crossing area toward the output window until the laser beam enters the output window and the output window transmits the laser beam to the hand piece; and wherein said optical cell comprises a gas fill with an energy threshold for ionization which energy threshold is increased in comparison to an energy threshold of ambient air.