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FrozenGate by Avery

Cyan Heart: Handheld diode laser at 488nm (HEAVY PICS)

CurtisOliver said:
It's an alright laser, could of thrown more money at it IMO! :crackup: JK, I'm not jealous at all. :whistle: :D

Seriously fantastic job. I would love to be the one owning the cyan heart right now.
plusreplpf.png
from me. Yellow OPSL portable next? :p
Click to expand...

Well, unfortunatelly, no OPSL is coming up :yh:
But I do have a couple of ideas to think about for building something intersting in future. The only problem is getting the parts. I have realized that any of high quality optical components are really hard to get (I am talking about parts for a specific application, f.e. lens with some required coating, diameter and focal length). So, this would be the wall for me right now. Thinking about solving these issues. :undecided: Will see.
 
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I am looking forward to see what you will do in the future. I'm guessing others on here are too. :) A 488nm handheld is an excellent project. :p
Parts are never easy to get hold of, unless you have lots of disposable income. :(
I hope you can resolve the issues with your new project. :beer:
 
Ivan, what a nice build/tutorial thread featuring such the beautiful 488nm cyan wavelength! :beer:
Handling that expensive diode had make you a tiny bit nervous I'll bet; the finished product is spectacular though.

I'll bet every single member here would love to have one of these in their collection!
:gj: and :kewlpics: +rep!
 
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It will be dark in a few hours for me, so will have a look for that beam then. :D
 
Alaskan said:
I wonder what the divergence is?

Screen%20Shot%202017-05-08%20at%206.23.38%20PM.png
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Well, I was trying to measure it today, but I think my calculations are a bit wrong, just because I am unable to find a perfect focus to infinity.
I tried to use my corridor, it is long enough. So, after a bit of time playing with the lens nut I got these (without the aperture cap):
At the aperture, the width of the beam is 4mm;
(note that I was measuring the slow axis)
At 2.5 meters, the width is 3mm;
At 6 meters, the width is 3.5mm with some interference pattern, but the most bright spot is near 3.5mm;
With these results, the divergence calculator gave me a value of -0.4mRad. This is probably because I had it focused to a spot much smaller than the beam size at the aperture.
As to my bare eye, this diode is very similar to 405 diode when talking about divergence.
The only problem (and the reason of that interference pattern) is the diode's window. I have noticed that the window of this diode is very dirty.
And it seems that this is not a dust or something similar, the problem is with the window's glass itself (I tried a hand air blower) -- it has couple of anisotropy points, which is damaging the beam profile:

IMG_8572.jpg


This is a really sad point about this diode :(
I was already thinking about removing the cap with window, but I dont know is it worth it or not.
When focused pretty well, the beam looks just fine. The only thing I want to do here is find a lens nut for reducing the size of collimated beam. After all, I don't really care if the spot size gets even near 1 cm at 15 meters. The tight beam going out of the aperture is always a beautiful thing. And since this diode has very low divergence, it should handle these kind of optics pretty well. I found something on Ebay and waiting for it to try, will see.
For now it uses a simple 3 element glass lens.
 
A better way to calculate it is to measure the spot at 1m and again at 20 m. I think you are getting an erroneous measurement at the aperture. I didn't realize you have a problem with the diode window. For the money you spent on this diode, to me, that is totally unacceptable. I would at least send a photo of it to the seller to see if they are willing to compensate you.
 
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Ivansuper said:
The only problem (and the reason of that interference pattern) is the diode's window. I have noticed that the window of this diode is very dirty.
And it seems that this is not a dust or something similar, the problem is with the window's glass itself (I tried a hand air blower) -- it has couple of anisotropy points, which is damaging the beam profile:


This is a really sad point about this diode :(
I was already thinking about removing the cap with window, but I dont know is it worth it or not.
Click to expand...

Amazing build. Great job.:drool:

Looking at that picture it looks like just a few tiny dust particles in the center an something a little bigger on the bottom but not in the main light path. If you are contemplating taking drastic steps like decanning I would attempt cleaning it first. I am sure it would clean up very easy based on what I see. Suggest cleaning it with some 97% alcohol or lens cleaning solution, a glue free q-tip and some compressed air before thinking about decanning.
 
DTR said:
Amazing build. Great job.:drool:

Looking at that picture it looks like just a few tiny dust particles in the center an something a little bigger on the bottom but not in the main light path. If you are contemplating taking drastic steps like decanning I would attempt cleaning it first. I am sure it would clean up very easy based on what I see. Suggest cleaning it with some 97% alcohol or lens cleaning solution, a glue free q-tip and some compressed air before thinking about decanning.
Click to expand...

Good idea. But for some reason I am afraid of any liquid applied to such an important place. One day I have had tried to clean G2 lens this way, and now it behaves even worse. But the idea with compressed air sounds good.

PS Your driver is not what it should be. Definitely :p
Just now tried another G2 lens from another laser and LPM now gives me stable 107mW for a time near a 1 minute. This is not even near the specified 60mW. Still working, not warm at all. I wonder now how big this diode is overdriven ... And if not, and you are sure the driver is working around 70mA, then I have got an extremely efficient unit.

paul1598419 said:
A better way to calculate it is to measure the spot at 1m and again at 20 m. I think you are getting an erroneous measurement at the aperture. I didn't realize you have a problem with the diode window. For the money you spent on this diode, to me, that is totally unacceptable. I would at least send a photo of it to the seller to see if they are willing to compensate you.
Click to expand...

Good point about the divergence. I have already found a way on how I would achieve this range without corrupting the beam. Will post result later.
As for the beam profile, I bet they would tell me that this is my fault. And, I have no proof to not resist this, although I have installed it very carefully, and no one of others in my collection is having a dirt/dust on its window.

EDIT:
I have done some poking with q-tips, as DTR suggested. Luckily, this helped a lot.

IMG_8574.jpg


Then I measured the divergence with G2 lens installed. The divergence is 0.72mRad, and the point size at 17 meters is 15mm.
Well, this was expected, because G2 gives more thin beam. Smaller beam size leads to bigger divergence.
I bet the spot at 17 meters with 3 element glass lens would be around 8mm, giving a bit smaller angle of divergence.
But I will stay on G2 here. At least because it uses almost all radiation emitted (far more, 88mW vs 107mW), and the beam is more tight and accurate.
 
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That looks a lot better. +rep DTR for the advice. What an amazing colour. :beer:
 
So is 622nm build on your list next?

Check out LDX 622nm laser diode... they come in 9mm package and cost a lot less than 488nm diode...$622 USD to be exact...or 503nm diode to match your LED... $2700 USD from you know who..
 
Ivan, nice job cleaning that window, looks great now.

On the difference between a three element lens and most versions of the so called and shorter FL "G2" single element aspheric lens sold by many sellers; three element lenses have about a 8 mm focal length which allows the beam to expand more prior to collimation and thus lower divergence, but I'm saying the same thing you did, in different words.

The three element has more loss, but the beam is wonderful. If you don't mind the loss, three element lenses are great for single mode diodes which won't have much, if any, of their output cut off inside the barrel diameter due to spreading too fast. Although due to the reduced power output of many single mode diodes as well as their inherent low divergence (compared to MM diodes), my choice would be some kind of single element aspheric lens like the G2 to allow more output power. Aspheric lenses are normally considered superior to PCX or bi-convex lenses for laser diode collimation too.

G2 Specs as sold by Laser 66: http://www.laser66.com/html/405-G-2.pdf

Planck, 622 nm, hmmm.... I'm going to check that out, shorter than 638 nm, especially by that much sounds interesting. Only thing, that diode should be run at 5 to 10 C, better at 0 C, so needs cooling. Spec: https://www.laserdiodesource.com/pdfs/product-109/622nm-150mW-TO-can-c-mount-LDX-Optronics.pdf
 
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Ivan, that looks much better, what a great improvement. I didn't think that a cleaning would help to this extent; I think I'd leave it as is and not try for any more improvements. :yh:
:gj:
 
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