Hi I have built a 600mW 808nm IR laser, the diode itself is a TO-3 open can type, but a simple laser pointer type lens just collimates the beam to a diverging line, what other optics do i require to correct this?
Its always going to diverge some, but if you let the beam expand a little before you collimate it, it will be less diverging. In my 2w laser, I used an old telescope eyepiece to collimate it, the focal length is about 1.25 inches. try using a lens that allows it to expand a bit before collimation. the more it expands, the more collimated the beam will be, but the bigger around it will be, my beam is about a half inch in dia. but it looks awesome at 2.2 watts!
thanks peeps, i know what NIR stands for lol, & i have discovered i need a fast axis collimator to correct this, i will give the old telescope optics trick a try however, as i cannot afford such a complex bit of optics at the moment