Noninterceptive Beam Profiling of High‐Power Industrial Lasers

Abstract

High-power 1 -100 kW industrial lasers typically undergo thermally-induced optical effects that change the laser beam and laser beam delivery to the work piece. Knowledge of any changes such as focal shift may be important for particular welding or cutting processes. Conventional beam profile diagnostic methods are not practical and fall short at such high powers. A new profiling technique that uses Rayleigh scatter from the beam overcomes the power obstacle and allows laser characterization that was previously impossible to perform.In high-power laser welding and cutting applications operating over "long" times at the minute scale, the delivery optics are heated and typically the focal spot shifts in position, and the spot size and other beam parameters also change. The higher the power, the greater the shift, and this could be critical to the process. With observed focal shifts on the order of 0

Fast Laser Beam Characterization

“…The highly concentrated light around the laser's beam waist is scattered off nearby air molecules; this phenomenon is captured by a camera from the side using a telecentric lens assembly on a CCD or CMOS camera, which allows for analysis of the laser's beam waist without ever touching the beam. The measurement technique needs no water cooling, has no moving parts, and there is no upper limit on the power of the laser to be analyzed [3]. And, since it is a camera-based system, it provides data up to 15 times per second, allowing the laser technician to see more time-based characteristics of the laser system: Specially-designed software provides size measurements of the laser focus (beam waist) as well as the location of the focus over time.…”

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…In laser-based devices, it is often the case that light travels through optical components before interacting with its target. The profile of the laser beam at the end of the optical track may differ from the desired one due to the heating of mirrors, lenses, and polarizers, which causes their deformation [8].…”

Development and validation of an inverse method for identification of thermal characteristics of a short laser pulse

“…Most of the available measuring devices cannot be applied for direct analysis of the high-power lasers in industrial environment and their response time and mounting is inadequate for fast or on-line measurements [9]. For example, the high sensitivity of the camera profilers requires the laser power to be reduced by many orders of magnitude using beam sampling or optical attenuation [10]. Recently a new profiling technique which based on the Rayleigh scatter from the beam have been proposed [10].…”

“…For example, the high sensitivity of the camera profilers requires the laser power to be reduced by many orders of magnitude using beam sampling or optical attenuation [10]. Recently a new profiling technique which based on the Rayleigh scatter from the beam have been proposed [10]. This method overcomes the power obstacle and allows dynamic measurement and diagnostic of the beam parameters as well as determination of M 2 parameters of laser beams with power from 1kW to 100 kW.…”

“…Thermophysical parameters of the aluminum alloy AW2017A T4[10]. Initial and boundary conditions as well as the laser beam parameters for the considered cases.…”