Concept and experimental implementation of a scalable high power and highly homogeneous laser line generator for industrial applications

Abstract

High power diode laser line generators are nowadays industrial standard for applications like plastic processing, vision inspection and drying. With increased beam quality, especially peak intensity and homogeneity, they also enable new applications like hardening, annealing or cutting of various materials. All of these applications have in common that simultaneous processing is limited by the scalability of the generated line length without changing process relevant parameters of the line like working distance, peak intensity, homogeneity and depth of focus. Therefore, a patent pending beam shaping concept is presented that enables the interconnection of an arbitrary number of nearly free selectable laser sources to generate scalable laser lines with outstanding beam parameters. System design, experimental setup and results of a laser line generator are shown. It is based on a stitching concept consisting of ten fibre coupled high power diode lasers, which generates a 200mm long and 2mm wide laser line with a homogeneity level of 97% p-v over a depth of focus of +/- 5 mm with an overall output power of up to 4.2 kW. The concept is discussed regarding industrial applications and the options for even higher beam quality, especially the capability of generating lines with increased power densities up to several kW/cm² and a line length of several meters.