Product Code: ICAL06_702

Optics Evaluation for Multikilowatt Solid State and Fiber Lasers
Authors:
Harald Schwede, PRIMES GmbH; Pfungstadt Germany
Reinhard Kramer, PRIMES GmbH; Pfungstadt Germany
Stefan Wolf, PRIMES GmbH; Pfungstadt Germany
Volker Brandl, PRIMES GmbH; Pfungstadt Germany
Otto Marten, PRIMES GmbH; Pfungstadt Germany
Presented at ICALEO 2006

Laser macro processing, cutting, welding, and drilling, with multikilowatt solid state and fiber lasers is gaining more and more acceptance in industry, e.g. car industry, aerospace industry, or ship yards because of increased performance, quality, and high reliability resulting in acceptable overall costs. Standard fused silica optics used in focussing systems for laser macro processing are widely known as "rock solid" with conventional lasers. With the new laser typs, with their higher beam quality and higher power level, the requirements on focussing optics are highly increased. Three effects can be observed with not well optimized optics: drift of focus position, distortion of beam profile, reduced beam quality. For the evaluation of the performance of focusing optics we have developed a laser focus analyzer which can be operated in the 20 kW range using an camera based optical imaging system. We will discuss the demands and constraints of multikilowatt focus analysis. The achieved performance, allowable power loading, and damage mechanisms of the analyzer system will be described. The main advantages of the analyzer system are the measured beam paramters of the real focus, the short measurment cycles of less than one minute for full caustic scan, triggered operation for pulsed laser beams, high geometrical resolution and nearly no limitation to power density in the laser spot. We will show measurement excamples with optimized high quality optics compared to conventional optics with new high beam quality multikilowatt solid state and fiber lasers.