Multimode Laser Beam Profile

Intensity profile of a multimode beam which has about the maximum possible m 2 value for efficient launching into the fiber.

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. B 3d beam intensity profiles of the multimode dpss laser at the constructed far field using a converging lens. 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. Here we investigated the effect of changing the input angle of a focused laser beam into a multimode fiber patch cable.

Focusing the light normal to the fiber face produced a near gaussian output beam profile figure 1 and increasing the angle resulted in top hat figure 2 and donut shaped figure 3 beam profiles. 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. Initial profile input angle 0. A comparison of gaussian and multimode beams with equal energy was carried out in order to estimate influence of beam profile only.

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.