BeamSquared® – Measurement of Long Rayleigh Range Lasers with Small Focal Spot

The development of remote material processing techniques requires increasing the accuracy of the process to permit creating smaller features. Laser systems, used for various industrial applications like material processing and micromachining, require small focal spots and at the same time, greater focal lengths.

Small focal spots and greater focal lengths at the same time

To achieve that, lasers systems combining larger beams, and lower M², combined with longer focal length lenses are used. This results in
smaller focal spots at longer distances from the laser and Rayleigh length, up to 20 meters.
A variety of single-mode fiber and solid-state lasers designated to meet the specifications of both a long-waist location and small focal spot size is now available on the markets. The laser systems require a new approach to
their beam analysis technique.

BeamSquared® – Higher measurement accuracy

Beam Propagation and Caustic analysis of lasers with small focal spot and long Rayleigh range performed by BeamSquared® (BSQ) equipped with conventional focusing lenses of 400 – 500 mm may not be ISO11146 Standard compliant due to pixel limitation of Beam Profiler camera.

The limitation occurs if the measured beam covers an area on the camera sensor less than 20 pixels in diameter. Even when the beam waist diameter is larger than 20 pixels, more accurate measurement results are achieved when more pixels are covered. An additional parameter of ISO11146 defines that the caustic propagation measurement space should be at least 4 times the Rayleigh length of the laser.

To support ISO11146 standard measurement of such lasers, longer focal length lenses with high focal length accuracy are required.

Ophir to the rescue!

Ophir now happy to introduce a set of lenses calibrated for accurate and repeatable propagation measurements of lasers having long Rayleigh length and small focal spot.

Read full article here