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ArcticMyst Security by Avery

Strange halo next to dot

T

TenderTendon

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Jun 20, 2012
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Hello,
Long time lurker with my first plea for help. This is my first build "from scratch", and I have an unusual artifact next to the dot. It is seen as the "hat" on top of the dot, and below the dot appears to be cut off. This is the 9mm Nichia with the lens that comes with it. I searched through image after image and couldn't find anything similar. This shot was taken at 130ma. but it is present at any power level. The lens is clean. The artifact does not follow rotating the lens, so it appears to be coming out of the can like this. The dot is un-affected. I can get it very sharp. There doesn't appear to be any obstruction in the apature anywhere. The diode and lens are centered very well. I included a pic looking down the apature into the lens. I can live with this, but if there's a way to eliminate or reduce it, I'm all ears. Thanks!

img0560j.jpg


img0573ljk.jpg
 
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Blord

Blord

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All 445nm diode have this behavior. I don't think you can do anything about it.

Aren't you getting the lens out and put it in the barrel ?
 
DTR

DTR

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Very nice job on that heatsink.:beer: It looks like a normal single element lens with the 445 diodes. Here is a good picture from Jay's thread on the G-1. The G-2 is the same way. It is way better than the artifacts that you get with the three element lenses. This is just a byproduct of the diode being a multi-mode diode.:)

445%20lens%202.jpg
 
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BShanahan14rulz

BShanahan14rulz

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TenderTendon said:
img0560j.jpg
Click to expand...

What shape is the artifact? Is it the massive rectangle above the line? I'd hazard a guess that it is scattered light being reflected back and illuminating the entire face of the die, which is in focus because of the aspheric lens.

If you look at a laser die head on while it is running (theoretically, obviously don't do this), you will see this block sitting on the gold pedastal, and a plateau on top of the block, barely distinguishable because it is so small. The active region and resonator cavity are in this tiny plateau.

So if you flip your image upside down and overlay it on top of another image of a diode face, I'd guess your artifact is the same width and height as the laser die.

It's been too long since I've read a PBD post, he needs to shine some more enlightenment this way :undecided:

edit: btw, this hasn't been proven, nor have I seen this idea anywhere else, but I'm just brainstorming/pondering.
 
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Wolfman29

Wolfman29

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There's no way you made those heatsinks manually unless you are very precise with your mill! Do you have a CNC?
 
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TenderTendon

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Wolfman29 said:
There's no way you made those heatsinks manually unless you are very precise with your mill! Do you have a CNC?
Click to expand...

These parts were made on my mini-lathe and micro-mill. I don't see why you feel I have to be very precise. These parts are quite ordinary. The only thing complicated was the material itself. Copper is a bitch to machine.
 
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Wolfman29

Wolfman29

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But... but... it's such clean machining! And the screws surrounding it, not being on axis, means that you had to do them on your mill... and they look perfectly spaced!
 
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TenderTendon

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All the work was done on the lathe except the screw holes. They were drilled on the mill while chucked in a small rotary table.
 
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