Kryton DIY Green laser

"he's got crystals that are already mounted in a coper heatsink capable of producing up to 300mw from a 2 Watt C-mount diode."


What!?!

--hydro15

hydrogenman15 said:

"he's got crystals that are already mounted in a coper heatsink capable of producing up to 300mw from a 2 Watt C-mount diode."


What!?!

--hydro15

Click to expand...

Is that disbelief that he's got crystals that innefficient, or that he's got crystals that efficient?

Since these mountings are already setup to have the crystal in the DEAD CENTER. I'm figureing it would be easy to thread it in and will always remain centered. From there it's moving the crystals away or closer to the diode.

Click to expand...

It's not just the centering that counts - that's probably not the hardest part... you do need independant control of rotation and distance from the pump, so that would result in requiring a thread to adjust for distance and then some secondary mechanism for rotation.

The other option would be to focus the pump light into a paralel beam, which takes the distance out of the equation to some degree. This would work similar to a red laser pointer, but the beam would have to be more narrow to fit the crystal - i doubt it can be done with a single lens.

Cheap pointers often omit all of the above, and just glue the crystal set nearly flush with the diode, perhaps with a predefined spacer in between. The only thing to get correct then is rotation. For example, many of the DX lasers are constructed this way.

If you'd go for superb performance, there are also thermal considerations: the crystal set has an optimum (in fact, both crystals in the set have their own optimum), and the pumps output wavelength depends on its temperature too.

All in all i think this project will be a major challenge, and it would require thourough investigation of all parameters before you can start turning barrels. There are a lot more things to get right (or screw up) compared to building just diode based red or bluray lasers. As these components will run pretty expensive, getting it wrong would be an expensive adventure.

Benm said:

Since these mountings are already setup to have the crystal in the DEAD CENTER.  I'm figureing it would be easy to thread it in and will always remain centered.  From there it's moving the crystals away or closer to the diode.

Click to expand...

It's not just the centering that counts - that's probably not the hardest part... you do need independant control of rotation and distance from the pump, so that would result in requiring a thread to adjust for distance and then some secondary mechanism for rotation.

The other option would be to focus the pump light into a paralel beam, which takes the distance out of the equation to some degree. This would work similar to a red laser pointer, but the beam would have to be more narrow to fit the crystal - i doubt it can be done with a single lens.

Cheap pointers often omit all of the above, and just glue the crystal set nearly flush with the diode, perhaps with a predefined spacer in between. The only thing to get correct then is rotation. For example, many of the DX lasers are constructed this way.

If you'd go for superb performance, there are also thermal considerations: the crystal set has an optimum (in fact, both crystals in the set have their own optimum), and the pumps output wavelength depends on its temperature too.

All in all i think this project will be a major challenge, and it would require thourough investigation of all parameters before you can start turning barrels. There are a lot more things to get right (or screw up) compared to building just diode based red or bluray lasers. As these components will run pretty expensive, getting it wrong would be an expensive adventure.

Click to expand...

If I didn’t know any better id say you’ve ripped apart a ton of DX greenies? ;D Very simple design in most of them, and a good source for parts. The newish type modules have the fast axis setups by way of two lenses in between the pump and the medium, and 2 paper thin brass shims to get the distance required.

I have found nice beefy crystal sets in typical 5mW leadlight pointers. They are about 5x the size of that found in any DX laser, each one having its own serial number etched into them. The one that I had time to test and play with gave me more than 30% efficiency, but I didn’t put it in front of a 1watt, so im not sure how far they can be pushed, or how susceptible they are to heat and mode issues.

I'm not saying that this is going to be "precise" or "optimum". In a newwish style pointer the setup is pretty simple and probably pretty easy to reproduce in a simple setting like my Kryton barrel. I'm looking at a cheap means of producing your own higher powered laser pointer and of course there will be a lot of different means to adjust both the crystals and the diode as well as the optics. The way I see it as long as your IR beam, be it focused or colimated, gets pumped into the center of the crystal and affects the crystals the way they are supposed to. The beam exits the crystals and goes to another optic or set of optics to colimate the output from the cyrstals. I don't understand how the rotation of the crystals from the diode is going to affect things. but as I've indicated I don't know a whole lot about the internal workings of the DPSS. I'm currently reading the page on DIY DPSS at sam's
http://www.repairfaq.org/sam/lasercds.htm

Kenom, this project really really interests me.

I was too late in joining this forum to get one of your groove barrels, however I did recently get a smooth blu ray unit from daguin.

If you were to source out the components (or even put together a full kit) you could count me in on being a part of it!

Mike

OK here is kind of what I'm looking at accomplishing inside one long threaded hole.

http://www.laspro.de/body_a.htm

Too bad I can't read German.

and here.  This is a Homemade 400mw Green DPSS laser. (at least according to sam's laser FAQ's)

http://www.missilistica.it/laser/dpss.htm

Kenom said:

[quote author=hydrogenman15 link=1225075706/0#16 date=1225160732]"he's got crystals that are already mounted in a coper heatsink capable of producing up to 300mw from a 2 Watt C-mount diode."


What!?!

--hydro15

Click to expand...

Is that disbelief that he's got crystals that innefficient, or that he's got crystals that efficient?[/quote]

Thats an efficiency of 15%. :-/ I think the power level will be what makes this practical.

--hydro15

I don't understand how the rotation of the crystals from the diode is going to affect things.

Click to expand...

Yet it does, this is easily demonstrated by dislodging the crystal set of a (cheap) green laser pointer, and rotating it in respect to the pump diode (or vice versa). It has something to do with an optimal polarization direction of the pump light relative to how the crystal is grown.

The german site is an excellent example of what you should try to accomplish, i think. It also suggests carefully adjusting the distance to the pump diode/lens first, and rotating for optmum output power after. On the end he mentions this is much the case for Nd:YVO, but much lesser for ND:LSB (i have no idea what that is exactly).

Also, he employs a thermostat mechanism to keep the pump diode at 25C, and suggests it would be beneficial to rig some kind of thermostat construction for the KTP, although it has not been implemented in that design yet.

I'm not saying that this is going to be "precise" or "optimum". In a newwish style pointer the setup is pretty simple and probably pretty easy to reproduce in a simple setting like my Kryton barrel.

Click to expand...

I would go for a much more precise setup than found in the simple DX pointer. In honesty, there is absolutely no point in recreating, for example, a laser with the performance of a 'true DX50' which ends up costing $100++ in parts.

If you are looking for that kind of performance, it would be better to use the complete diode-crystal-lenses assembly from such a DX pointer, but mount it in a case with better cooling and provide a better driver and batteries for it. Lets be realistic in that respect: a DX pointer sources you all the parts required, and could be brought to great performance using a proper casing and power supply. If you could combine a ~$100 laser from DX with ~$50 in casing a driver to form a stable 100 mW+ green laser, that is an achievement in itself!

I think someone should try a proof of concept test to see how much energy we can get out of the crystals.

--hydro15

here ya go... kinda helps

http://translate.google.com/transla...?q=http://www.laspro.de/body_a.htm&hl=en&sa=G

http://translate.google.com/transla...www.missilistica.it/laser/dpss.htm&hl=en&sa=G

Why not shoot for the 473nm blue instead of working on a DIY green? I mean, at this point in time, it's not hard for any of us to buy a (working) green laser at any decent power.

What we really can't get is a blue. I know, there is pretty much no way I can afford a blue, unless it's a 5mw and I save for a very long time. I really think that you should shoot for bringing blues to the people instead of greens :-/

simplysped2 said:

Why not shoot for the 473nm blue instead of working on a DIY green? I mean, at this point in time, it's not hard for any of us to buy a (working) green laser at any decent power.

What we really can't get is a blue. I know, there is pretty much no way I can afford a blue, unless it's a 5mw and I save for a very long time. I really think that you should shoot for bringing blues to the people instead of greens  :-/

Click to expand...

We need to make greens before we start going for blues cause there REALLY complicated and inefficient.

--hydro15

simplysped2 said:

Why not shoot for the 473nm blue instead of working on a DIY green? I mean, at this point in time, it's not hard for any of us to buy a (working) green laser at any decent power.

What we really can't get is a blue. I know, there is pretty much no way I can afford a blue, unless it's a 5mw and I save for a very long time. I really think that you should shoot for bringing blues to the people instead of greens  :-/

Click to expand...

because it is not likely to be done by us. you need some expensive tools to align everything correctly and to get any sort of blue you will need a lot of power from your pump diodes...

take a look into this 473nm blue module



much more complicated

Anything is possible to those determined enough!!!

I'd have to agree on the green-first idea.

The crystal sets for green dpss have made major improvements in the last couple of years. Alignment isn't super-duper-critical to get at least a glimmer of green and optimize from there... I suspect this will be much much harder with a blue dpss - the processes being as inefficient as they are there, you'd have to get it exactly right to get any result at all.

It would probably be best to get some relatively availble to get parts (pump, crystals) and try to replicate the result from the german page. With readily available i mean parts that can be obtained in the future too by others - mind you that all crystal sets are different and interchanging them will not always work.

The variability in parts makes this already a much bigger challenge compared to the red/bluray barrel that will work with almost any diode that more or less fits mechanically.

I can read german to a reasonable degree, so if there are any translations required for an attempt i'd be happy to give it a go!