Multimode Laser Beam Profile

As the input angle was increased the proportion of meridional rays to skew rays increased first forming a top hat and then a donut beam profile.

Multimode laser beam profile.

For example light from stationary high power lasers of various types can be sent to material processing stations for cutting or welding where e g. Multimode fibers are used for the transport of light from a laser source to the place where it is needed particularly when the light source has a poor beam quality and or the high optical power requires a large area of the fiber core. Single mode lasing gaussian beam results in better reproducibility of analytical signals compared to multimode lasing while laser energy reproducibility was the same for both cases. B 3d beam intensity profiles of the multimode dpss laser at the constructed far field using a converging lens.

A comparison of gaussian and multimode beams with equal energy was carried out in order to estimate influence of beam profile only. Here we investigated the effect of changing the input angle of a focused laser beam into a multimode fiber patch cable. Modifying beam profiles with multimode fibers by increasing the launch angle of a gaussian beam into a multimode fiber the output beam profile can be modified. The maximum beam spot size is 3 4 mm at z 0 and at 50 cm away from the laser it becomes 5 8 mm.

The figure below shows the intensity profile of a monochromatic beam from a numerical simulation where the power is well spread over all guided modes.