Dear all,

This is my first post here. I have checked the forum but I didn't find anything that could help me on other posts, but I wanted to give it a try if anyone has already done anything similar to what I need.

I have been checking several fiber laser up to 250W for 1060-1080nm. I need a laser spot at a working distance of 1.2-1.4m, so I am not looking for a small spot size, I need it to give heat a material. So, my idea was, as the specs of the fiberlasers have a good beam quality (M^2 <1.3) I expect that a fiber laser without any lens, or only with a collimator or beam expander, would be enough to achieve a spot size of 2.3mm at the distance of 1.2-1.4m. Am I correct? I don't have the chance to test this, and I am going to ask some providers for quotations, but I don't know if my assumption is correct.

I have heard that the beam angle divergence stablishes the beam diameter "growth" for a meter distance, I mean, 1mrad beam divergence = 1mm/m diameter growth per meter distance. Is this correct?

Thank you to all,
iosef