High Power Density Focusing Optics™, HPDFO for short, is a patented system composed of a collimator and a specially designed HPDFO lens kit. The collimator expands and “straightens” the beam as it exits the laser, and then the HPDFO lens kit focuses the laser beam onto a much more concentrated spot than can be practically achieved with standard optics systems, increasing the power density of the laser. In order to produce a similar spot size using standard optics, the focal length would need to be as short as .75″ to 1″, which is too short to be usable in most applications. These optics allow the laser beam to be focused to a much smaller spot, producing sharper images at tighter tolerances. It’s particularly suited to intricate engraving and direct marking on some metals.