The Direct Diode Laser (DDL) is a laser oscillator that uses a prism and lenses to concentrate the laser beams coming from a Laser Diode (LD) stack module made up of semiconductor laser arrays. Laser beams. Direct diode lasers are laser devices where the output of laser diodes is directly used for an application — frequently in laser material processing, e. This eliminates the need for a complex beam delivery system, resulting in compact equipment, making it possible to combine multiple diode lasers to produce a powerful laser beam. Much of what will be discussed will be in general terms of laser diode performance, warnings, and tips.