635nm C-mount Lab Laser

I know Jack over and Opto has some good optics, maybe give him a buzz.

lazeerer said:

Hey Have you tried the 2 lenses that are above the Red LED.?

There are 2 lens in that black section. I think the are Coated for Red too. There is One below and one above. The one below is Smaller then the one above.


Not sure How much of the Projector you actually had and if the Phatlight LED was still in there.

Click to expand...

This is a good idea!!.. I'll have to take a look at it again. If they are coated I would think that they would be for the red wavelength. I haven't touched the LED from the strip down hoping to find some way to fire it up at some point(too many projects..........)

@ Toaster....I'm going to put in a small order through surplus shed, they have the lens that i'm interested in trying, even though not coated for the wavelength

Edit: you know looking at that picture I think that i'll have to take that thing apart and look at it's over-all use for perhaps housing a C-Mount diode itself. MMMMMMMMM(creative juices flowing....)...............(usually i'm too poor to purchase items that were actually made for their use)

Well. If you do not want to take your apart my offer is still there. I have quit a few to say the least.

I can ship you the black part with the lenses if you wish. No Charge.

Send me a PM.

Thats very cool of you!!! I may take you up on that....:beer::beer:
I still think that LED has great potential for some cool project of some sort.

I'll strip mine apart tomorrow and take some pictures of what I find inside and with the lens applied to the 635nm

MMMMM!!!!!!

I seem to be running into some trouble here....as I leave it on for a longer time it seems to be loosing intensity. Now I would think that this thing is more than heat-sinked with the jig and copper backing.

What i'm seeing is that the flares that are coming out of the top and bottom in the pictures above are fading and the square in the center is loosing it's intensity as well. I would think that this is a symptom of higher heat and that might be but it seems that I have that base covered and TEC cooling might be over the top.

Now i'm afraid to leave it on for a longer period, so far not much longer than 5 min(WAY OFF SPEC from what I was looking for).
It's a bit late now so i'll get back to work on this thing tomorrow and see what I can see, hopefully nothing is wrong.
Micro-Flex @800mA
Regulated 3V 1A wall adapter.,,,,,mmmmmmm???

Yes let me know.

You dont even want to know what iam doing with them.>:evil:


Edit:

Just seen you second Post above^^^. Hmmm not sure. I dont think its do to heat. Those heatsinks are pretty big. However it has to travel through that bracket that the C mount is on. This might be heating up allot faster then its able to transfer the heat to the larger heatsink.

Maybe tec cooling will solve this.

Forgive me if I've overlooked something, but is the TEC running? I can only see one set of wires going to the diode.

Because if it isn't running, a TEC is a damn good insulator. And if that's what's happened, chances are you've already wrecked the diode.

Also, for collimation, none of the lenses from the projector will work as an initial collimation lens.

You'll be looking for something with an extremely short focal length, and positioned near (as in <1cm) to the diode's die. You might want to use corrective optics such as a prism pair or cylindrical lenses after the collimator. The XJ-A140 lenses would work well for a beam expander, though.

None of the Crapio lenses would be suitable; Thorlabs or similar might have the appropriate lens. You'll never be able to get proper collimation with any of the Casio lenses (just like how it's near damn impossible to collimate a laser diode with a magnifying glass).

I'm no optics expert (that'd be Mister Cyparagon), however, what I do know is you will need the ultra-short focal length lens near the diode itself. You can use one of those alone, or in conjunction with another long focal length lens to make a beam expander of sorts.

Your best bet for a collimator is jayrobs aspheric for 650.. As mentioned above
you want it close to the die as possible...

An aspheric will bring the lens in nice and close for parallel focus, then you need
to either add Dr.Lavas cylindrical set or a prism pair.

Your going to lose a lot of power if your collimator doesnt sit right
on the LD..

You can also use an aspheric with the lens from the red LED on
the projector as an expander, but your initial beam width is gonna be
pretty big..

Ive had a few cmounts from coherent that use an aspheric then prisms.
Seems to be the ideal config..



Just a quick note, if the diode is dropping output, you may want to
back off the current a bit..

@532, even though it will be difficult I think some experimenting and input from those with knowledge here, will get you a reasonable, but not perfect beam. Certainly not a narrow beam, but one that doesn't diverge horribly.

Great work on a worthwhile project! :beer:

goninanbl00d said:

Forgive me if I've overlooked something, but is the TEC running? I can only see one set of wires going to the diode.

Because if it isn't running, a TEC is a damn good insulator. And if that's what's happened, chances are you've already wrecked the diode.

Also, for collimation, none of the lenses from the projector will work as an initial collimation lens.

You'll be looking for something with an extremely short focal length, and positioned near (as in <1cm) to the diode's die. You might want to use corrective optics such as a prism pair or cylindrical lenses after the collimator. The XJ-A140 lenses would work well for a beam expander, though.

None of the Crapio lenses would be suitable; Thorlabs or similar might have the appropriate lens. You'll never be able to get proper collimation with any of the Casio lenses (just like how it's near damn impossible to collimate a laser diode with a magnifying glass).

I'm no optics expert (that'd be Mister Cyparagon), however, what I do know is you will need the ultra-short focal length lens near the diode itself. You can use one of those alone, or in conjunction with another long focal length lens to make a beam expander of sorts.

Click to expand...

Thanks all for the input.....
There is not TEC, I had discussed it earlier in my other thread and we had decided that the metal heat-sink should be enough. It's only 300mW diode and not a 1-2W 808nm. I'v also been checking the diode after I use it every time just to see if its all right still. Seems so, all Five of the tiny wires on it are still attached and the FAC looks okay too.
I wonder if the voltage or current is dropping for some reason as it heats up?
I turned it on for a a few seconds again this morning and it's back to looking like it's old output, so I don't think that i'v done any damage to it yet.

@ wannaburn: I'v been looking at the prism pairs and been think about them. The diode does have correction through the FAC so I was hoping to avoid them and just use the lens, but if I have to....I have to.
Perhaps someone knows what lenses are in Dr.Lavas cylindrical set? My rig is really set up more for larger lens and I would really have to work it to get that little lens up close and adjustable. The prism pair I think I could work into the design a bit easier though if I end up needing them

Also with the current, I could give it a try turning it down. I thought I set it at a pretty conservative range of 800mA, by the sheet..it looks like the threshold is 643mA and I should be getting around 200mW of the 300-350mW with it set to 800mA.

Thank you all for your input here with the Optics, I'v been trying for a while now to get anyone with a bit of knowledge to chime in. I'm really surprised just how little all of us know about optics!(I think we need to have a class)


Edit: I just put in an order through Surplus Shed for some optics to work with.....
SKU: PL1107
PRECISION PCX LENS 30MM DIAMETER, 1000MM FL
Lens: PCX, Dia: 25, Focal: 41,
Lens: PCX, Dia: 28.1, Focal: 561, Coated
Lens: PCX, Dia: 35, Focal: 175, Coated
Lens: PCX, Dia: 26.5, Focal: 48, Coated
Lens: PCX, Dia: 27, Focal: 33, Coated
Lens: PCX, Dia: 24, Focal: 61, Coated

I still need to find Anamorphic Prism Pairs....I left a PM on PL and I also see a pair from that 473nm labby that people are buying from Ebay. If anyone here has an extra pair that they would like to sell please post here or PM me. I'm starting to think that I may need these, but hopefully the lenses that I have coming will correct most of my troubles.

My experience with optics is just like anything else with lasers.. trial and error.

None of my red c-mounts have FAC so I have not tried any combinations
with that type of diode, but if anything it should make it easier..

The coherent 670nm LD I have does have it, and it still was set up with
an aspheric and prisms.. But keep in mind it was originally a 'pumping' module
so there is reason for extra optics there.. Still produces a square beam though.

Jayrob sells the 650nm AR for 25$ IIRC which is a good start for a collimator..
In the setups ive tried with aixiz lenses, the loss was really high, they sit
too far away from the LD.

With Lava's optic set, there are 2 pieces, couldnt tell you what the specs for
them are, but you only need the set and a collimator to get your beam..
The smaller of the two can be mounted right on the collimator, and the second
sits within 20mm which also acts as an expander.. Im sure there a some unused
sets floating around here somewhere.

If you need a prism pair, I have a few sets left but they are coated
for 808.. Not sure what the losses would be like. They are the sets from
the 473nm labby's..

Heres a pic of a really ugly 635. This one was a damage LD, but you can
see how fast the beam spreads.. The rest of the raw output cant be seen
here, but was much longer. I mounted this with indium and was experimenting
with a damaged LD before even considering the same setup with a good LD..

wannaburn said:

My experience with optics is just like anything else with lasers.. trial and error.

None of my red c-mounts have FAC so I have not tried any combinations
with that type of diode, but if anything it should make it easier..

The coherent 670nm LD I have does have it, and it still was set up with
an aspheric and prisms.. But keep in mind it was originally a 'pumping' module
so there is reason for extra optics there.. Still produces a square beam though.

Jayrob sells the 650nm AR for 25$ IIRC which is a good start for a collimator..
In the setups ive tried with aixiz lenses, the loss was really high, they sit
too far away from the LD.

With Lava's optic set, there are 2 pieces, couldnt tell you what the specs for
them are, but you only need the set and a collimator to get your beam..
The smaller of the two can be mounted right on the collimator, and the second
sits within 20mm which also acts as an expander.. Im sure there a some unused
sets floating around here somewhere.

If you need a prism pair, I have a few sets left but they are coated
for 808.. Not sure what the losses would be like. They are the sets from
the 473nm labby's..

Heres a pic of a really ugly 635. This one was a damage LD, but you can
see how fast the beam spreads.. The rest of the raw output cant be seen
here, but was much longer. I mounted this with indium and was experimenting
with a damaged LD before even considering the same setup with a good LD..

Click to expand...

Thanks for all that input. I'v put in a good order with surplus shed to do just as you said, experiment a bit and see if I can make things work.
The one thing they didn't have was a prism pair. I'll PM you.

By the way, even though it's a poor output for a beam,......Nice Pic! My camera just won't pickup on the lines and blurs it all out in light.

In reading this thread, I'm left feeling like there must be a more objective way to determine the appropriate lenses, rather than trial and error. IE, given that the divergence degrees for both axes are known (roughly), there must be a mathematical formula (even if complicated) that could produce figures for lens focal length, and position from emitter.

Right now I'm sort of "not really here" (don't have permanent internet access setup yet). But in a few weeks, if someone is able to tease out some math for the above, I'd be happy to put it together into a web-app tool. I was already planning to turn cyparagon's diffraction grating math into a tool, so I could tackle this while I'm at it.

Anyway, great work 532, I'm really enjoying this thread.

"there must be a mathematical formula"

I was allowed to take Logic instead of Math:banghead: at my college.

There are formulas for this, and an app has been posted before (cant find the link).

Considering most of us use harvested parts, experimenting is key.. Besides, why
take the fun out of things with math

Optics are fairly simple if you know what your goal is. The only thing I have found
needed to be specific is the coatings.. and even then there is a ton of tolerance..

Any aspheric that sits close to the LD for a parallel focus is the starting point..
You can adjust the aspheric leaving the second lens static and get the desired
results simply by adjusting the focus.

WWMD?



@532, returning PM...

wannaburn said:

Any aspheric that sits close to the LD for a parallel focus is the starting point..
You can adjust the aspheric leaving the second lens static and get the desired
results simply by adjusting the focus.

WWMD?

Click to expand...

You have some great photo's man! I love this one!

I have to ask....why an aspheric? what would be the difference between using that or a plano-convex as first optics? I'v seen these used as first optics off the diode, but i'v also seen plano-convex....:thinking: