Fiber Laser Collimator

[jlrsamuel]

It is my understanding that a collimator is required when using a fiber laser to cut materials such as metal. Collimating makes the rays parallel allowing the beam to focus properly through a focusing lens (in a nut shell). Any thoughts on what would happen if I did not use a collimator and used just a plano/convex lens in an attempt to focus the beam? Low power and cutting plastic.

TIA,

JLR

[LightComm]

or the laser diade might burn down

[Riner]

It is my understanding that a collimator is required when using a fiber laser to cut materials such as metal. Collimating makes the rays parallel allowing the beam to focus properly through a focusing lens (in a nut shell). Any thoughts on what would happen if I did not use a collimator and used just a plano/convex lens in an attempt to focus the beam? Low power and cutting plastic.

TIA,

JLR

You could use a plano/convex lens but then you would need to design to focal point exactly. A collimator is a device that narrows a beam of particles or waves. To "narrow" can mean either to cause the directions of motion to become more aligned in a specific direction. The advantage of using a collimator is that you don't have to worry so much about the focal point/length.

[Timelord]

Another point is that the collimator inserts the relatively parallel beam path section that allows the Z axis of the cutter table to be adjusted, as Riner suggests, your focal point will be relatively fixed, moving a single lens will also vary the focal spot size. In addition, if the beam path length from the collimator position, usually at the fiber's outlet aperture, to the new single lens is significant it may also require a larger aperture single focusing lens. What does your whole beam path look like? What is the divergence angle without the collimator?

Timelord