Traditional focusing optics for IR lasers are refractive lenses and off-axis reflective mirrors. ZnSe meniscus and plano-convex lenses dominate the refractive lens types in use today for CO2 laser cutting, welding, marking, and engraving systems, to name a few of the more common applications.
Silicon and copper spherical mirrors that are used near normal incidence and off-axis copper parabolic mirrors dominate the type of reflective mirrors used in very-high-power CO2 lasers for welding and heat treating. These types of mirrors are made with common polishing and diamond-turning techniques that are well known.
In the last three years, advances in fabrication techniques have allowed optic manufacturers to produce more advanced optical surfaces on metal and refractive materials. This paper will provide details of some of these novel focusing optics for IR laser applications. The paper will include design details of ring-focus off-axis parabolas, focused flat-top generators, toroidal lenses and mirrors, faceted integrators, and long-radius off-axis parabolas. Both design and theoretical performance will be given for the optics. In some cases, laser test data will also be provided.