Magneto-optic Kerr effect metrology systems

A method comprising:

• directing a laser beam through an transmissive axicon telescope thereby transforming the Gaussian beam profile of the laser beam to a hollowed laser ring, wherein directing the laser beam through the transmissive axicon telescope includes:
• directing a laser beam with a Gaussian beam profile through a first axicon lens and a second axicon lens;
• directing the laser beam with the hollowed laser ring through an objective toward the wafer, wherein the objective is a Schwarzschild reflective objective;
• and
• adjusting a gap between the first axicon lens and the second axicon lens whereby a diameter of the laser beam with the hollowed laser ring is adjusted while collimation is constant;
• directing the laser beam with the hollowed laser ring at an optical component, wherein the optical component is a beam splitter or a fold mirror;
• directing the laser beam with the hollowed laser ring toward a wafer;
• directing the laser beam with the hollowed laser ring reflected off the wafer to a focal lens;
• and
• receiving the laser beam with the hollowed laser ring from the focal lens at a detector.