Subtractive Laser Processing Using Extended Depth of Field Focusing

The removal of material through ablative processes has been studied extensively since the development of the laser. As applications employing such processes have become increasingly complex, requiring precise control while increasing speed and throughput, more advanced methods of beam delivery have been developed to achieve these goals. One important emerging methodology is the use of high depth of field optical elements to produce a line focus or other higher dimensional intensity patterns. In contrast to traditional beam focusing where the light is concentrated to a single location in xyz space, by using high depth of field focusing, it is possible to efficiently deliver energy through an extended region of space, thus gaining a number of important benefits for subtractive laser processing. This chapter reviews some of the current methods of producing a high depth of field and discusses the implications and benefits of such approaches for marking, cutting, and drilling of opaque and transparent materials.