Laser micromachining through a protective member

A laser micromachining system that removes target material from a workpiece, comprising:

• a laser beam source emitting a laser beam that propagates along a beam path for incidence at a target location on a working surface of a workpiece, the laser beam removing target material from the workpiece at the target location and thereby producing ejected target material spewing in a direction away from the working surface;
• a lens positioned in the beam path to focus the laser beam at the target location on the working surface of the workpiece, the lens set at a working distance from the working surface of the workpiece, the working distance being sufficiently short to permit unimpeded spewed ejected target material to reach the lens;
• and
• a sacrificial protective member positioned between the lens and the working surface of the workpiece, the sacrificial protective member transmitting without appreciable distortion and adsorption the laser beam focused by the lens and incident on the working surface, and the sacrificial protective member intercepting the ejected target material to prevent a sufficient amount of it from reaching and thereby appreciably contaminating the lens.