Diode Upgrade?

GVLLD M981 · Apr 25, 2014

I had an old 5mw, 532nm pen that sucked particularly bad, so I took it apart, removed the driver board, and pulled the diode out. So just for giggles, I ordered a 400mw, 808nm diode and appropriate driver board, and am waiting on those. But if anyone can possibly answer, I have a couple of questions going in: How many ma should the original one have been, to get "5mw" output, as claimed? I know that the original wanted 300ma input, and I looked at 2 diodes, both wanted 400ma in, one was 300mw out, and the one I got was 400mw. I assume that this will give more power, but I am just guessing, since I have nothing better to do, or do with the dead pointer. Does anyone know what the factor is for diode to output ratio for these dpss lasers?

Teej · Apr 25, 2014

GVLLD M981 said:
I had an old 5mw, 532nm pen that sucked particularly bad, so I took it apart, removed the driver board, and pulled the diode out. So just for giggles, I ordered a 400mw, 808nm diode and appropriate driver board, and am waiting on those. But if anyone can possibly answer, I have a couple of questions going in: How many mw should the original one have been, to get "5mw" output, as claimed? I know that the original wanted 300mw input, and I looked at 2 diodes, both wanted 400mw in, one was 300mw out, and the one I got was 400mw. I assume that this will give more power, but I am just guessing, since I have nothing better to do, or do with the dead pointer. Does anyone know what the factor is for diode to output ratio for these dpss lasers?

The cell(s) powering them are the input to the driver....after that, its just a question of how hard the driver drives the diode.

Its like the driver of a car, if two drivers have identical cars (Batteries and diodes, etc), but one driver is set to drive with the pedal to the metal, and the other driver is set to drive at idle, they will have different "output ratios".

The idling driver will of course get better mpg, but will be more boring.

The pedal to the metal guy will get terrible mpg, but you might be awake the entire trip, etc.

So, you SET the driver to drive the diode at YOUR desired pace, and, depending on the working limits of the diode, you would say push it as hard as you thought you could get away with w/o frying it too soon.

Going from 532 to 808 nm might mean the wiring is different, I don't know your two set ups, but sometimes one takes the cells positive to the head, and, some take it positive to the tail (Opposite of most flashlights).

So, take a good look at the wiring set up before doing the swap....in case they are less compatible, etc.

PS - 808 nm means you will need safety goggles meant for that nm range...especially as the beam might be invisible to you, etc....and its easy to reflect it back into your eye w/o noticing. Your 445 nm goggles probably don't include 808 nm for example.

ChaosLord · Apr 25, 2014

I think the OP is wanting to replace the dead ir diode in his pointer with a new one. He's not switching wavelength, just getting a new pump diode, right?

If that is what your doing, the first thing I thought of was I'm not sure 808nm will work. I'm not one hundred percent sure, but I think 532 dpss generally uses a longer wavelength, deeper into ir. So if the diode you removed was 1200+nm, the crystals may not react to 808nm.

I know very little about dpss, but if you did "upgrade" the diode, 100mW extra ir may show a tiny boost in 532 ouput.

GVLLD M981 · Apr 25, 2014

ChaosLord said:
I think the OP is wanting to replace the dead ir diode in his pointer with a new one. He's not switching wavelength, just getting a new pump diode, right?

If that is what your doing, the first thing I thought of was I'm not sure 808nm will work. I'm not one hundred percent sure, but I think 532 dpss generally uses a longer wavelength, deeper into ir. So if the diode you removed was 1200+nm, the crystals may not react to 808nm.

I know very little about dpss, but if you did "upgrade" the diode, 100mW extra ir may show a tiny boost in 532 ouput.

That is exactly what I am going to try to do. I tried once, already, with a diode from a cd burner, but that failed. From what I could gather, reading and not just asking stupid questions, it has to be 808nm. I just wondered if anyone had a clue what kinds of diodes would get what out of a green dpss, there has to be some loss incurred between the pump diode and the cavity. I do think that this will give up more power, though, since I am sure that I am going to be using a more powerful pump diode. If it works at all, that is. This might be a way to get more power on a budget, or at least be something neat to do with dead green laser pens.

KRNAZNBOY · Apr 25, 2014

No, 808nm pump is what you want.

To be blatant, you will probably fail in your quest. Lining up DPSS optics is a b1tch, and you need to be VERY experienced to do it. Even though all the crystals are already arranged, the diode will have to be identical, mm to mm in specs and orientation if you want any output at all.

IF you manage to get it to work, chances are your efficiency will be about 5-15% IMO.

Best case scenario, you will get about 30mw.

Sorry, but this (probably) simply can't be done.

If you want a working and of quality 532nm pen, visit laserbtb.com

:beer:
-Matt

Teej · Apr 25, 2014

KRNAZNBOY said:
No, 808nm pump is what you want.

To be blatant, you will probably fail in your quest. Lining up DPSS optics is a b1tch, and you need to be VERY experienced to do it. Even though all the crystals are already arranged, the diode will have to be identical, mm to mm in specs and orientation if you want any output at all.

IF you manage to get it to work, chances are your efficiency will be about 5-15% IMO.

Best case scenario, you will get about 30mw.

Sorry, but this (probably) simply can't be done.

If you want a working and of quality 532nm pen, visit laserbtb.com

:beer:
-Matt

LOL

It didn't even occur to me that he was trying to match a set.

I thought it was to just make the pen an 808 nm.

:thinking:

crazyspaz · Apr 25, 2014

KRNAZNBOY said:
No, 808nm pump is what you want.

To be blatant, you will probably fail in your quest. Lining up DPSS optics is a b1tch, and you need to be VERY experienced to do it. Even though all the crystals are already arranged, the diode will have to be identical, mm to mm in specs and orientation if you want any output at all.

IF you manage to get it to work, chances are your efficiency will be about 5-15% IMO.

Best case scenario, you will get about 30mw.

Sorry, but this (probably) simply can't be done.

If you want a working and of quality 532nm pen, visit laserbtb.com

:beer:
-Matt

youd be surprised- these cheap chinese modules are easy as pie to realign. Just sticky the already algined and glued together crystal set on its mount, not even rotation dependent- just get it over the diode until you see the most green, really, then glue it down.

Flaminpyro · Apr 25, 2014

KRNAZNBOY said:
No, 808nm pump is what you want.

To be blatant, you will probably fail in your quest. Lining up DPSS optics is a b1tch, and you need to be VERY experienced to do it. Even though all the crystals are already arranged, the diode will have to be identical, mm to mm in specs and orientation if you want any output at all.

IF you manage to get it to work, chances are your efficiency will be about 5-15% IMO.

Best case scenario, you will get about 30mw.

Sorry, but this (probably) simply can't be done.

If you want a working and of quality 532nm pen, visit laserbtb.com

:beer:
-Matt

Isn't it funny how these 14 year old kids come here and learn a couple things and then they know it all, to be Blatant they will tell some one it can't be done
and I'd bet $100.00 he hes never tried it him self, yea lets tell some one any thing just so we can get our opinion out there whether it's right or not :crackup:

crazyspaz said:
youd be surprised- these cheap chinese modules are easy as pie to realign. Just sticky the already algined and glued together crystal set on its mount, not even rotation dependent- just get it over the diode until you see the most green, really, then glue it down.

ultimatekaiser · Apr 25, 2014

There's alot of variables here. more than just getting it all lined up correctly that will affect the output of the green. more pump power, means different mode structure and divergence. alignment of the crystal and surfaces is only one slice of the pie. to get max efficiency, and an increase in power, you have to take into account the new mode spacings, and modes involved...you'll also have to factor in heat. not just cooling for the diode and module, but what waveshift this will cause, as well as how it will affect the crystal's happiness. even a nm shift decreases your output drastically. IR diodes for this are special, usually wave locked, and the crystals get hot easy, from normal pumping, let alone getting heat from the body instead of the other way around. too much heat from the casing can make it worse to the point of damage as well as the loss of the lasing line(s) you want. they're optically contacted, but enough stress can fracture the crystal and coatings. polarization and thresholds have to be noted as well. dropping in a new diode will likely emit some green, but most of the time, your gains are usually modest at best, and are short lived due to the additional stresses...plus...more power usually results in a wider, and more square, and more unstable input, and you need good mode limiting to get quality results. those small modules are only made to do about 5mW. pushing them beyond about 10 and they overheat pretty quickly. that's why the ebay pens are so short lived, they're grossly overpowered for their size, and they can't take the stress.

lots of extra IR not absorbed....heat
more pump power in the same small space with no cooling...heat
rotation is off by even fractions of a millimeter...heat
angle is off...heat
longitudinal modes wrong...you guessed it. more heat, as well as tons of transverse hopping and hotspots.

its a fun experiment i've done before a couple times. it sometimes works once in a blue moon, with tinkering...but its usually not worth the effort without a bigger cavity and crystals.

Teej · Apr 25, 2014

ultimatekaiser said:
There's alot of variables here. more than just getting it all lined up correctly that will affect the output of the green. more pump power, means different mode structure and divergence. alignment of the crystal and surfaces is only one slice of the pie. to get max efficiency, and an increase in power, you have to take into account the new mode spacings, and modes involved...you'll also have to factor in heat. not just cooling for the diode and module, but what waveshift this will cause, as well as how it will affect the crystal's happiness. even a nm shift decreases your output drastically. IR diodes for this are special, usually wave locked, and the crystals get hot easy, from normal pumping, let alone getting heat from the body instead of the other way around. too much heat from the casing can make it worse to the point of damage as well as the loss of the lasing line(s) you want. they're optically contacted, but enough stress can fracture the crystal and coatings. polarization and thresholds have to be noted as well. dropping in a new diode will likely emit some green, but most of the time, your gains are usually modest at best, and are short lived due to the additional stresses...plus...more power usually results in a wider, and more square, and more unstable input, and you need good mode limiting to get quality results. those small modules are only made to do about 5mW. pushing them beyond about 10 and they overheat pretty quickly. that's why the ebay pens are so short lived, they're grossly overpowered for their size, and they can't take the stress.

lots of extra IR not absorbed....heat
more pump power in the same small space with no cooling...heat
rotation is off by even fractions of a millimeter...heat
angle is off...heat
longitudinal modes wrong...you guessed it. more heat, as well as tons of transverse hopping and hotspots.

its a fun experiment i've done before a couple times. it sometimes works once in a blue moon, with tinkering...but its usually not worth the effort without a bigger cavity and crystals.

So, NOT just gluing it when it looks more green?

:crackup:

Not having attempted it, it never occurred to me it was easy to do, but then I saw the "Just get it more green" post, and was thinking, maybe I'm over thinking it?

Now, I see I'm glad I didn't "just go for more green and glue" etc.

Of course, its also why I thought the OP was just trying to make a 808 nm pen.

Thanks for the great explanation!

:thanks:

KRNAZNBOY · Apr 25, 2014

Flaminpyro said:
Isn't it funny how these 14 year old kids come here and learn a couple things and then they know it all, to be Blatant they will tell some one it can't be done
and I'd bet $100.00 he hes never tried it him self, yea lets tell some one any thing just so we can get our opinion out there whether it's right or not :crackup:

Still pissed at me? All right. I was told you might do that :crackup:

And yes I tried it last month with a fasttech module. It took me 20 minutes just to get it glued in the right place, even then, I only had a low efficiency and poorly aligned module.

Can I have my $100 now?

I never said it can't be done. I said it is difficult and results will probably be poor.

And my age doesn't matter. Quality of info matters. Right now, telling off a 14 year old is bullcrap that no one wants to hear. What people want to hear is info about the given subject. I thought that I did that, and you certainly did not.

If you want to keep doing this, which is fine by me, you need to get your facts straight before you make assumptions. I hope you haven't been doing this all your life

To the OP.
go ahead and try it. You may be surprised! It will be a fun learning experience regardless.

:beer:
-Matt

Teej · Apr 25, 2014

KRNAZNBOY said:
Still pissed at me? All right. I was told you might do that :crackup:

And yes I tried it last month with a fasttech module. It took me 20 minutes just to get it glued in the right place, even then, I only had a low efficiency and poorly aligned module.

Can I have my $100 now?

I never said it can't be done. I said it is difficult and results will probably be poor.

And my age doesn't matter. Quality of info matters. Right now, telling off a 14 year old is bullcrap that no one wants to hear. What people want to hear is info about the given subject. I thought that I did that, and you certainly did not.

If you want to keep doing this, which is fine by me, you need to get your facts straight before you make assumptions. I hope you haven't been doing this all your life

To the OP.
go ahead and try it. You may be surprised! It will be a fun learning experience regardless.

:beer:
-Matt

LOL

I remember many years ago when Video Stores opened and people were getting VCR's for the first time, and the joke was that your VCR would just blink 12:00 over and over again, forever, unless you could find a 12 year old to program it.

At 14, you might be TOO old now.

KRNAZNBOY · Apr 25, 2014

Teej said:
LOL

I remember many years ago when Video Stores opened and people were getting VCR's for the first time, and the joke was that your VCR would just blink 12:00 over and over again, forever, unless you could find a 12 year old to program it.

At 14, you might be TOO old now.

Some people think that cause they are older, they are smarter. Regardless of experience. I can't change that. I also can't change my crying rep page.

In all my year of being on the forum, I have never got neg rep for trying to help someone. That is when you can tell a grudge is involved

Teej · Apr 25, 2014

KRNAZNBOY said:
Some people think that cause they are older, they are smarter. Regardless of experience. I can't change that. I also can't change my crying rep page.

In all my year of being on the forum, I have never got neg rep for trying to help someone. That is when you can tell a grudge is involved

Sometimes its just chemistry. I just let it go and just worry about me.

In the long run, it all works out.

On the other hand, I was young, and, I remember feeling the same way you do right now...and its frustrating to know stuff, but have the adults not respect you for it, or, even resent you for thinking you know more than they do.

Interestingly, as I gained more and more life experience, I gained some perspective on what I actually knew, and realized that my life experiences to that point were not as encompassing as they had felt to me when I was younger.

I try to remember that when I talk to those older than I am (Running out of them lately though....), and realize that they are young kids who thought they knew every thing when they were kids, then, realized that they didn't when they were middle aged...but also realized that they still knew more than they did when half as old, and so forth.

IE: You don't really know less as you get older...you can keep learning.

So, take what you managed to learn by 14, ignore the first few years where it was about learning to use the toilet, etc....and imagine what you might be able to learn in ANOTHER 14 years.

And then another 14 years, etc.

It does add up.

Its something you can look forward to. As you're learned a lot in the first 14, you should be a rocket scientist by the time another 14 has rolled by, etc.

Enjoy it!

ultimatekaiser · Apr 25, 2014

Nailed it on the head. Though back on topic.

The Lightning Stalker · Apr 26, 2014

I haven't attempted this yet (though it is something I want to try) but I will tell you what I do know. The
diodes in these things are usually run at around 300mA. Since these modules are usually made of
brass, a replacement diode should not be pushed past its rating or else it will die. I have heard of these
being pumped with upwards of 500mW successfully, but that is way beyond their ratings and not all will
survive that kind of abuse, but some will, at least long enough to play around with.

You will also need glasses that reduce 532 and block 808 and 1064nm. Those don't come cheap. It
will cost as much as a few new lasers, so it isn't a viable option to just repair 1 bad unit. This is only for
someone who wants to 'play around' with DPSS.

Also keep in mind that weak output can sometimes be a problem with the crystal set itself and pushing
more power into it won't gain as much as using a good set. It's harder to justify breaking a working
laser though if it has good output. Sometimes we just make due with what we are "given".

Diode Upgrade?

GVLLD M981

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Teej

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ChaosLord

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KRNAZNBOY

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Teej

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ultimatekaiser

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Teej

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