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Easy Solution for Beam Improvement of 445nm Diode






Jmillerdoc

Jmillerdoc

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I read carefully but didn't pay too close attention to the picture ...looks as if you used a lens with the housing around it at first glance...the link appears to be a bare lens...on review though it appears that's exactly what you used:) so, of using the STD AixiZ thread and lens depth would you need to increase the depth of the lens chamber? How thick are these biconcave lenses?
 
foulmist

foulmist

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Cyparagon said:
Divergence?
Click to expand...

at aperture I get 5mm and at 5 meters I get 10mm.. Can this be right? I can't be sure if it set to exactly infinity... It's pretty hard to tell.

so that would make a 0.9999996666668668mRad? :thinking:

what's the mRad of a normal build with no expansion lens?

EDIT: Ok now I focused it better I get 6 to 7mm at 5 meters.
mRad = 0.39999997866666875 ? I am getting confused :D

Jmillerdoc said:
How thick are these biconcave lenses?
Click to expand...

2mm high, 5mm wide
 
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Jmillerdoc

Jmillerdoc

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I just unscrewed the lens out of a 5mw green module I had laying around. When I get home tonight I am going to try to fit it into one of my 445's and take some LPM readings for everyone. Not sure how well it will work as it's not the exact same lens but it should give some idea of the power change. I am hoping it will pass 95% or better...if it does every one of my blues will get this mod...next project will be the horrible 635.... Hopefully this will help that as well....
Great mod! I was hoping I could find an easy fix...
 
foulmist

foulmist

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not all dpss lenses expand the beam the same way. I just tried one (and it was plastic :D it was very bad (don't try it if it is plastic).. It stars melting right away :D
 
Cyparagon

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Hmm... 0.3mRad, round, and only 5% loss?

i-call-dibs.gif


:)
 
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Benm

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Bionic-Badger said:
I wonder about the losses too... is it just blocking off the edges like those circular light blockers on the cheap red laser lenses?
Click to expand...

I seriously doubt its that simple: The narrow side of them as emitted near the output lens becomes the wide part of the resulting bar in the far field. So simply adding a circular aperture would not help things at all.

Still, i'm curious about the power loss too - i imagine that some of the output must be clipped to get this kind of an improvement with circular optics of any kind.
 
rocket689

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Nice result. :) It will be interesting to see the power loss. :pop:
 
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danefex

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Awesome!! I'm also curious what the power loss is..... + :beer:
 
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saabluster

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It is quite clear what is going on. The concave lens is broadening the beam so much that the next lens can't capture all the light. The narrow side of the beam although getting expanded as well started off smaller and can still manage to be collimated. That's my story anyway. No free lunch I say. LPMed it would show a loss commensurate with the amount of missing area in the beam plus some loss for the optic. Doesn't sound like an improvement to me but I have other goals than some I guess.
 
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foulmist

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Cyparagon said:
Hmm... 0.3mRad, round, and only 5% loss?

:)
Click to expand...

well I didn't say anything about 5% loss... I know it is way over that. About the divergence.. I have never ever measured it before and I am not exactly sure what am I doing... sort of..

and the line does get a little bended from the center to the edges so when focused to infinity it is not a line anymore but more of a smudged line ..

and the beam doesn't get round it just gets, well - expanded. It is just somehow filling in the empty space at the top and bottom of the line.. at expense of power of course at the edges of the line...

EDIT: this is not a solution for all .. I just thought I find it easy enough and still remain some usable power for everybody who would like to see a more "rounded" shape of the 445nm beam.
I made this for me and to share my experience with you :)

I removed my lens last night, started on the laser and I didn't like it as much as with the lens. so I put it back :D although I have a big power loss I like the shape more :)
 
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DrSid

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I was playing with this a bit .. my concave lens perfectly fits Aixiz lens inner diameter, so it was really simple.
And I think this wont work. The concave lens are too strong. The widen the beam a lot. I think what we see on the pictures is indeed just middle of the beam enlarged and cropped, so most of the energy is gone.
Also the beam is problematic to focus. I could not do it with aixiz lens. I would have to dismantle them to get the back element closer to concave lens. Maybe even then it would not work, the concave lens (at least the one I have) is simply too strong.
 
Cyparagon

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foulmist said:
well I didn't say anything about 5% loss...
Click to expand...

I know. Someone else did though. :shhh:

You need to focus the dot on something FAR away... something like 30 meters minimum to have it collimated properly. Otherwise you're just focusing it at 10ft
 
foulmist

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Cyparagon said:
I know. Someone else did though. :shhh:

You need to focus the dot on something FAR away... something like 30 meters minimum to have it collimated properly. Otherwise you're just focusing it at 10ft
Click to expand...

I don't have big enough room here. :D I will try it outside somewhere but I don't know when... and yes we see the center of the beam larger that's what happening... I don't know what to do now... should I keep it with a lens or remove it?

What do you guys think? :thinking:
Since I don't have a LPM I can't measure the power loss, although it's still pretty strong... Is there a lens that can correct the slow axis without cropping it and make it better? I mean single lens not a set of lenses that will take too much space... :thinking:
 
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