New system monitors laser beams in visible and infrared wavelengths
MKS Instruments has launched a new non-contact beam profiling system, Ophir BeamWatch Plus, for measuring focus shift, focus spot size, and position of high power industrial lasers operating in the VIS and NIR range.
Introduced at the Laser World of Photonics, BeamWatch Plus is a second-generation system that now measures high power lasers in VIS wavelengths (420-635nm), primarily green and blue lasers, in addition to the NIR region (950–1,100nm).
Designed for very high power YAG, fibre, and diode lasers used in industrial material processing applications, BeamWatch Plus is ideal for welding and cutting operations in material processing and automotive applications, such as copper welding for battery cells and hairpin welding.
The system takes continuous measurements, using the Rayleigh scatter caused by the beam. This provides instant readings of focus spot size, beam position, and the full beam caustic, as well as dynamic measurements of focal plane location during process start-up. Measurements of the beam are taken at frequent intervals without having to shut down the process or remove extensive tooling and fixtures.
“Because there is no contact with the laser beam, BeamWatch Plus has no power restrictions,” said Reuven Silverman, General Manager at Ophir Photonics. “It has been successfully used on high power lasers with no upper power limit and tested up to 100kW. Conventional beam measurement systems place a probe in the beam, causing potential damage and slowing the measurement process to as long as two minutes to gather data and characterise the beam. BeamWatch Plus provides instant readings of focus spot size and beam position, as well as dynamic measurements of focal plane location during process start-up.”
The BeamWatch Plus profiling system features high magnification optics that measure beams with spot sizes down to 45µm. This allows for smaller, more precise cuts with less waste of material. Focal spot location can be measured at several times per second to track if there is any focal spot shift during critical start-up moments. The system provides a dual axis measurement, which lets users see the laser beam from two orthogonal axes. Measurements are calculated on each axis, providing detailed information about how the laser is operating. Focal shift can be tracked on both axes and the measurements can be used to determine the roundness of the beam or the presence of astigmatism.
Its software accurately analyses the images created by the laser’s Rayleigh scatter in real-time. Calculations are made of beam waist size and position, focal shift, M2, divergence, and other quality parameters. Key laser performance parameters are compared against preset ranges to provide Go/No-Go readouts so the laser user knows when to take corrective actions. The software also includes an Automation Control Interface for system integration.