System technology for dynamic beam shaping

Abstract

Since the power of continuous wave laser sources have reached one kilowatt, beam shaping is an important topic in the sector of laser material processing. The high intensity allows the increase of process speed, but the extreme local overheating often decreases the quality. Typically beam shaping solutions use a static beam adaptation by optical elements. For laser cutting for example, the increase of sheet thickness requires larger Rayleigh length what will be achieved by adapting the conditions of the incident ray at the focalization element. In this case the cutting quality increases but the cutting speed decreases. The advantage of high intensity gets lost. The dynamic beam shaping is known from the electron beam, and already applied in laser hardening and welding applications using galvanometer scanners. While the galvo-systems reached the physical limitations, the frequency is not high enough to achieve the desired effects. Resonance galvanometer scanners are limited by the atmosphere damping, too.This paper will introduce a new possibility of dynamic beam shaping, using MEMS technology in a low pressure atmosphere. It describes the reached steps to transfer the technology from display and sensor applications with low apertures and laser power to laser material applications with large apertures and high laser power. Finally, the technology possibilities are disclosed for the complete field of laser application.Since the power of continuous wave laser sources have reached one kilowatt, beam shaping is an important topic in the sector of laser material processing. The high intensity allows the increase of process speed, but the extreme local overheating often decreases the quality. Typically beam shaping solutions use a static beam adaptation by optical elements. For laser cutting for example, the increase of sheet thickness requires larger Rayleigh length what will be achieved by adapting the conditions of the incident ray at the focalization element. In this case the cutting quality increases but the cutting speed decreases. The advantage of high intensity gets lost. The dynamic beam shaping is known from the electron beam, and already applied in laser hardening and welding applications using galvanometer scanners. While the galvo-systems reached the physical limitations, the frequency is not high enough to achieve the desired effects. Resonance galvanometer scanners are limited by the atmosphere damping, too.T...