Abstract: A device for calibrating a laser beam system includes a calibration member having a surface positioned at a predetermined distance from the base datum of the unit. Further, the system includes a mechanism for focusing the beam to a focal point and for moving the focal point relative to the surface of the calibration member. When the focal point reaches the surface of the calibration member, Laser Induced Optical Breakdown (LIOB) is induced. Thereafter, the position of the location of LIOB may be measured relative to the base datum to calibrate the laser beam. Further, patterns may be applied to the calibration member using LIOB to calibrate tilt/decenter of the beam and to determine the energy density and uniformity in the focal spot of the laser beam.