Fiber lasers are up and coming for deep engravings. They work by sending pulses of light through a fiber-optic cable, the light bounces off the sides creating a certain wavelength. At the end of the tube there are mirrors that are computer controlled which direct the laser beam down on to what you are engraving. You can engrave a variety of materials from metal to leather with high precision for detailed engravings. Fiber lasers are also capable of marking stainless steel to produce a color.