A laser processing system in which a laser beam propagates along a beam axis and through a lens for incidence on a work surface of a target specimen mounted on a support. The lens forms a focal region of the laser beam. The support is operatively connected to a multiple-axis positioning system that moves the laser beam and the target specimen relative to each other to position the laser beam at selected locations on the work surface. An assembly includes at least one flexure that supports the lens and guides movement of the lens along the beam axis in response to a motive force to adjust the focal region of the laser beam relative to the work surface.