Buying from BarnettUnlimited is safe. My orders always arrive quickly. https://www.ebay.com/str/Barnett-Unlimited?_trksid=p2047675.l2563Thanks, and after searching for a bit i found out you can buy of this forum, seems a bit sketchy, is it safe?
I was wondering if i should get the 7w nubm44 module or the 2w m140 module, the thing is i'm concerned that the beam divergence on the 7w laser is to much when looking at the beam at night, is it to noticeable if you used a 3 element lens?Buying from BarnettUnlimited is safe. My orders always arrive quickly. https://www.ebay.com/str/Barnett-Unlimited?_trksid=p2047675.l2563
Sorry if this is a retarded question, i just got started building lasers and cant find anywhere to buy laser hosts, and also is dtrs laser shop still alive?
An expander will decrease the fast and slow axis. Will it still be noticeable yes. But your personal level of tolerance is what matters. A suggestion would be to use a cylindrical lens pair to correct both axis. Or just one cylindrical lens to correct the fast axis. That will create a square-ish beam that at some distance will look round.I was wondering if i should get the 7w nubm44 module or the 2w m140 module, the thing is i'm concerned that the beam divergence on the 7w laser is to much when looking at the beam at night, is it to noticeable if you used a 3 element lens?
Just to clarify:Yes the divergence of the NUBM44 is 3 times as wide as the m-140, with a 3E lens the m-140 looks like pretty much like a beam when shown into the far field, but the 44 makes a noticeable line, granted the m-140 makes a line 1/3 as long but is looks a lot better to the naked eye when viewed safely, even at short distances viewed through laser safety glasses you can see how much more divergent the nubm44 is, all mine use beam expanders and/or c-lens correction, for desktop duty I still enjoy a 7875.
To be clear, he is talking about the beam profile. The NUBM44 has an axis that is three times as divergent as the M140 diode. To correct for that we use both 6X cylindrical lens pairs and beam expanders to tame its wild divergence. The cylindrical lens pairs are mounted very close to the collimating lens. The BE is then put on the outside of the host at its aperture.Just to clarify:
1) You said "the m-140 makes a line 1/3 as long" Does this mean the M-140 beam is 1/3 as long as a NUBM44 beam when looking at the beam from the side at a distance? So the NUBM44 beam has a roughly 3 times longer reach into the sky?
2) At distances beyond roughly 100 - 200 ft, does the NUBM44 beam have a more or less intense beam toward the end point of the beam when compared to the M-140? Just asking because even though the NUBM44 is more powerful than the M-140, that power is spread out over a wider beam.
3) Is it correct to assume a beam expander (like the Sanwu) will make a NUBM44 beam look like a M-140 beam in terms of beam divergence? Or is the NUBM44 beam too wide to expect that much of an improvement using an expander?
Thank you for your input.