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Fun with a Ruby laser Rod [pic heavy]

KapHn8d

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nifty!

Thanks for sharing... good stuff.


/c
 



Benm

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The pictures don't seem to work from my connection, anyone else having problems too?
 

paul1598419

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Why are we in this old thread? Is there something new that isn't apparent from the new posts? Last time I talked to ultimatekaiser he hadn't done anything more with this rod. I've seen these types of rods before and one only pumps the Cr3+ doped part. The mirrors are separate and are placed parallel to each other at an integer number of 694nm times in length. This is most easily done with the use of a He-Ne laser. Anyway, that's all I know about this particular thread.
 
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ultimatekaiser

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This is an ancient post....and no, I sold this rod, but I do have 2 others that are much higher quality now, as well as an HR. I have made small ruby lasers...it's not too hard. finding the optics at a good price is hardest. assembly isn't too bad. Lamps are stupid expensive though.
 

Radim

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I just noticed this thread was revived. Whatever nice pics. I dreamed about getting ruby laser in the past. They are reminding me the physics history.

Seeing this awesome fluorescence I have to ask: Did you try to experiment with something else than flash lamps for pumping to get laser? If I remember well, there was diode pumping discussed, but I did not find whether it might actually work.
 

ultimatekaiser

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It's theoretically possible with 405nm diodes, but at the time the power required was unattainable. Nowadays, might be possible with stronger diodes... But you'd need so much power it'd be difficult. Flash lamps are probably really the only realistic way of a getting the power density needed while maintaining a good setup. Would be a fun experiment if I had the time and money though.
 

Richard Mally 2nd

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..thanks for the responses...glad forum is alive and well....old post??..not to the new guy ��...diode pumped maybe with the 3.6w blues available today... always wanted to make a ruby laser since 1963/4 when at the tender age of 7 i read and reread an article in reader's digest.." lasers the light fantastic "...i guess maybe I. 2012 or so some place in Europe made a cw ruby...didn't make it in the market though... couldn't find out much on the innards though...maybe 532 pump...
 

Radim

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It's theoretically possible with 405nm diodes, but at the time the power required was unattainable. Nowadays, might be possible with stronger diodes... But you'd need so much power it'd be difficult. Flash lamps are probably really the only realistic way of a getting the power density needed while maintaining a good setup. Would be a fun experiment if I had the time and money though.

Thanks. I could imagine some little rod diode pumped with high powered 405 nm. Since laser diode has narrower spectre and is absorbed well, therefore I guess the efficiency of conversion might be much better than with flashlamp with much wider spectre, where only tiny part is accepted. Still, the question is, if diode pumping is sufficent to create sufficient popullation inversion, as you mentioned.
 

Peter Zeboroff

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Indeed. just to clarify it's not 'lasing' it's just 'excited' there isn't stimulated emission happening here in full, except perhaps a little bit at the core under the herc usage...but any gain is lost to to ruby long before it leaves the rod laterally in any significant amount. you need flashlamps to operate a ruby laser. End-pumping simply won't do it realistically. I hope I can obtain some mirrors someday to make a laser out of it.
Hi, Did you ever finish your Ruby Laser? I too am and have been extremely fascinated with Ruby Lasers for many decades and I too have acquired a suitable Ruby Rod which is 240mm long and 15mm in diameter and I too am hoping to one day build a laser that actually puts out the brilliant deep red laser pulses. I am looking for anyone willing to help me in the acquiring parts for it as well as all the calculations needed to calculate how many input joules I will need to reach threshold and how many capacitors in general I need. I will be using two 5000 joule flash lamps. If you are interested in sharing info or helping me in any way, please contact me.
 

ultimatekaiser

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That’s because they’re not anymore. The original picture host changed it’s policy in those pictures no longer exist. I’m sorry I haven’t replied as I haven’t been on in quite a while I do have several rods and mirrors, but none are presently in a laser.
Making a ruby laser isn’t super hard, but it is pretty challenging nowadays to find all the parts.
 

Peter Zeboroff

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That’s because they’re not anymore. The original picture host changed it’s policy in those pictures no longer exist. I’m sorry I haven’t replied as I haven’t been on in quite a while I do have several rods and mirrors, but none are presently in a laser.
Making a ruby laser isn’t super hard, but it is pretty challenging nowadays to find all the parts.
I have also been gathering the parts to build a Ruby laser for close to 60 years now. I finally found a suitable high quality New rod 240mm long and 15mm in diameter with perfectly polished and parallel ends. It has also taken me several decades to find some suitable di electric mirrors that are specifically made for high power Ruby Lasers. Ruby laser mirrors essentially do not exist in the used laser market and the companies that make these mirrors want an absolutely absurd amount of money to make a pair of them. Now I am trying to find the proper 3 axis adjustable mirror mounts that will hold the 30mm wide and 10mm thick mirrors. Of course after that I will need the two linear flash lamps I intend to use with this rod and of course a fairly large number of proper capacitors. Can you recommend any good and reliable sources for the capacitors? E bay is full of them but I also happen to know that the Chinese have fooded the world and most likely E bay with counterfeit and totally fake capacitors as well as just about every other component. I would greatly appreciate any advice or help in acquiring the rest of the components needed and then to calculate the proper capacitance needed and the amount of capacitors that I will require. Also once I have all the required components, I want to either make or have made a proper 2 piece Aluminum housing that will hold the Rod and the Flash Lamps and be sealed so I could have it liquid cooled which will likely be milled out of solid aluminum. I forgot to ask you,what is the largest Rod you have and would you ever consider selling any of your larger Ruby Rods?
 

ultimatekaiser

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I've worked with some really big ones, the largest being from a Korad machine that was quad pumped and about the size of a billy club/baton. I could've beat someone over the head with it. it was huge. The large one that I do have I don't remember the size of. most of the ones I use are quite small, around 3" long. It's quite hard to pump a ruby the bigger it gets, as you run into thermal issues and saturation problems.

I agree mirrors are hard to find, they were never common to begin with. a lot of old robust ones are destroyed from age, and new ones are expensive if not made in bulk. (true of any dielectric mirror frankly) a lot of the best ruby lasers were small, and often q-switched, using a prism and an unique etalon like optic at the front as they would last forever, since no coatings are involved that way rather than having to worry about degrading mirror coatings would from the high intracavity powers involved, though at the expense of power. You can often get by with only an HR and use a glass optical flat as an OC. be careful not to use 2 HRs or something too highly reflective or you can blow the coatings right off the mirrors. OC mirrors for ruby rods are only like 30-40% reflective in alot of cases, though some can be closer to 70% depending on the size and dopant levels of the rod.

Capacitors of that size are expensive, I imagine you cand find them at outlets like mouser, or by contacting places directly, but I wouldn't expect them to be cheap. HV parts are pretty niche now in the modern era and not really commonly available as much as they used to be. I'd have to do some research but I imagine you can find them with some hunting from old equipment or from other hobbyists, as well as from ebay with some care. I'm not sure how easy they'd be to find on places like mouser and such, but that'd be preferable to get them new if you can, and not cheap china-lytics. I wonder if you could find good supercapacitors that can tolerate that kind of voltage. the low impedance would be fantastic i'd imagine.

Your main challenge will be coming up with a decent cavity if you want it to have any kind of permanence. pumping a large rod is no joke and produces a substantial amount of heat. two lamps should be enough if they're well coupled to the rod, but that'd take some doing. thicker rods are quite hard to saturate, and if you don't get them fully saturated they will not lase, as they will reabsorb their own laser light unlike a YAG. The problem then becomes heat, as ruby does not conduct heat nearly as well as YAG does and uneven cooling, overpumping, and such can obviously cause the rod significant thermal stress from so much input and can shatter or crack the rod.

I'd focus on making your cavity first, and then worry about power supply after. you'll need a very rigid something to build it on, and to mount your mirrors, and you'll have to make a cavity that is reflective withe the rod and lamps mounted sturdy and with the light well coupled into the rod, and electrically safe. the rod will need to be mounted on the ends with as little waste as possible, so you minimize places light cannot reach.

a picture of your rod might help too. Is it one of those russian ones off ebay that has the transparent ends, that are doped only in the middle? They're not the best quality, but I've been told they do an ok job.
 

Peter Zeboroff

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I've worked with some really big ones, the largest being from a Korad machine that was quad pumped and about the size of a billy club/baton. I could've beat someone over the head with it. it was huge. The large one that I do have I don't remember the size of. most of the ones I use are quite small, around 3" long. It's quite hard to pump a ruby the bigger it gets, as you run into thermal issues and saturation problems.

I agree mirrors are hard to find, they were never common to begin with. a lot of old robust ones are destroyed from age, and new ones are expensive if not made in bulk. (true of any dielectric mirror frankly) a lot of the best ruby lasers were small, and often q-switched, using a prism and an unique etalon like optic at the front as they would last forever, since no coatings are involved that way rather than having to worry about degrading mirror coatings would from the high intracavity powers involved, though at the expense of power. You can often get by with only an HR and use a glass optical flat as an OC. be careful not to use 2 HRs or something too highly reflective or you can blow the coatings right off the mirrors. OC mirrors for ruby rods are only like 30-40% reflective in alot of cases, though some can be closer to 70% depending on the size and dopant levels of the rod.

Capacitors of that size are expensive, I imagine you cand find them at outlets like mouser, or by contacting places directly, but I wouldn't expect them to be cheap. HV parts are pretty niche now in the modern era and not really commonly available as much as they used to be. I'd have to do some research but I imagine you can find them with some hunting from old equipment or from other hobbyists, as well as from ebay with some care. I'm not sure how easy they'd be to find on places like mouser and such, but that'd be preferable to get them new if you can, and not cheap china-lytics. I wonder if you could find good supercapacitors that can tolerate that kind of voltage. the low impedance would be fantastic i'd imagine.

Your main challenge will be coming up with a decent cavity if you want it to have any kind of permanence. pumping a large rod is no joke and produces a substantial amount of heat. two lamps should be enough if they're well coupled to the rod, but that'd take some doing. thicker rods are quite hard to saturate, and if you don't get them fully saturated they will not lase, as they will reabsorb their own laser light unlike a YAG. The problem then becomes heat, as ruby does not conduct heat nearly as well as YAG does and uneven cooling, overpumping, and such can obviously cause the rod significant thermal stress from so much input and can shatter or crack the rod.

I'd focus on making your cavity first, and then worry about power supply after. you'll need a very rigid something to build it on, and to mount your mirrors, and you'll have to make a cavity that is reflective withe the rod and lamps mounted sturdy and with the light well coupled into the rod, and electrically safe. the rod will need to be mounted on the ends with as little waste as possible, so you minimize places light cannot reach.

a picture of your rod might help too. Is it one of those russian ones off ebay that has the transparent ends, that are doped only in the middle? They're not the best quality, but I've been told they do an ok job.
Hi, I took some photos of my Rod and will try and post them here. The Rod has no markings or damage on it of any kind and has chromium from end to end. Its 240mm long and 15mm wide.Please tell me what your opinion of this Ruby Rod is?20210925_013137.jpg20210925_013145.jpg20210925_013220.jpg20210925_013250.jpg20210925_013315.jpg20210925_013417.jpg20210925_013417.jpg
 




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