Wakrah
Active member
- Joined
- Jan 9, 2021
- Messages
- 90
- Points
- 28
I purchased two 700 mw 638 nm diodes from DTR today, the Sharp GH0637AA2G and the Oclairo HL63193MG, I will test both of them and take photo's. Will likely use the DTR G8 lens.
Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers
Buy Site Supporter Role (remove some ads) | LPF Donations
Links below open in new window
FrozenGate by Avery
Which Diode has the best Divergence:Power Ratio?
- Thread starter gazer101
- Start date
Wakrah
Active member
- Joined
- Jan 9, 2021
- Messages
- 90
- Points
- 28
We had one fellow on here in the past, probably still active under a new ID now though, who claimed his NUBM44 had uber low divergence with a lens which was far too small to produce the amount he claimed. I believe he was focusing the beam down to a spot and thought that was the divergence. Divergence can only be measured at infinity focus, and finding infinity focus can be problematic, for one thing, with our laser diodes we have the fast and slow axis, each with their own individual amounts of divergence, then you must be sure the focus is really set to infinity focus. If beyond infinity, the beam will spread faster, if inside infinity focus, the beam will converge to make a smaller diameter spot in the distance due to that, but not at infinity.
When I want to find infinity focus, I take my pointer outside and rotate the pointer until I see the wide side of the beam, then while watching and pointing strait up, adjust the focus back and forth to see it get wider each way I turn from infinity focus, that way I know I found it, then try to estimate how much to turn the focus to be half way between each direction I turn to where I see the beam get wider at the far end of the beam, thousands of feet up.
There is another way you can do this though, if you have a plano convex cylinder lens, when the beam is set to infinity focus, the cylinder lens will produce a fine line on the wall, or upon some structure far away, adjust the focus back and forth until the line is as sharp and fine without blur as you can get it, then you are at infinity focus. When at infinity focus, it doesn't matter how near or how far from the cylinder lens you place the pointer, the result will be the same fine line, if out of focus from infinity, the focus of the line will change as you move the pointer closer or further away from the lens.
When I want to find infinity focus, I take my pointer outside and rotate the pointer until I see the wide side of the beam, then while watching and pointing strait up, adjust the focus back and forth to see it get wider each way I turn from infinity focus, that way I know I found it, then try to estimate how much to turn the focus to be half way between each direction I turn to where I see the beam get wider at the far end of the beam, thousands of feet up.
There is another way you can do this though, if you have a plano convex cylinder lens, when the beam is set to infinity focus, the cylinder lens will produce a fine line on the wall, or upon some structure far away, adjust the focus back and forth until the line is as sharp and fine without blur as you can get it, then you are at infinity focus. When at infinity focus, it doesn't matter how near or how far from the cylinder lens you place the pointer, the result will be the same fine line, if out of focus from infinity, the focus of the line will change as you move the pointer closer or further away from the lens.
