What kind of rod is it?

[Alaskan]

Guys, can someone give me an opinion of what you think this is? I'm being told it is a ND YAG by the seller and someone else who saw the photo that it is ND Glass, probably Russian manufacture.

 

[BowtieGuy]

Looks like a glue stick to me. :crackup:

 

[GSS]

Looks like a glue stick to me. :crackup:

:crackup:

 

[BobMc]

I’m gonna go with a glass rod.

(Sorry couldn’t help myself).

 

[CurtisOliver]

It's really hard to tell just from a few images. As both Nd:YAG and Nd:Glass appear pale pink/purple like that.
How does it compare to the other YAG rods you have?

 

[Alaskan]

I think it looks like a glue stick too. I don't have it, but wanted to know. ND glass rods have end sections on them like this, I have also seen end caps made out of sapphire for high pulse energy rods too.

e: I believe the reason my YAG expert buddy, from the above photo's, thinks they are ND Glass is due to what appears to be end sections on the rod, but this morning I've viewed more photo's which give the impression it is one continuous rod. If so, it must be a YAG. The color looks right for a YAG, glass is usually a bit richer hue, but lighting can affect it so much too.

Here's a ND:glass which appears pink:

https://www.ebay.com/itm/Neodymium-ND-Glass-Laser-Rod-100x5mm-/222697580367

Here's one which appears blue:

https://www.ebay.com/itm/GLS-9P-9-Neodymium-Nd-Phosphate-Laser-Glass-Rod-10-x-260-mm/152628606906



One of the reasons ND Glass is used for decorative glass is how it can appear either light to dark pink, to blue, depending upon the lighting. There is so much to learn in this hobby, obviously, I'm still learning about these rods.

 

[CurtisOliver]

It could have a lower dopage intended for pulsed output. Just a thought.

 

[Richie89]

Looks like a glue stick to me. :crackup:

I agree! I think it’s a glue stick

 

[Alaskan]

I think these are all low dope level rods made for flash lamp pulsing.

 

[styropyro]

I think these are all low dope level rods made for flash lamp pulsing.

FYI, lower dopant levels are found in rods for CW lasers, not pulsed output. Peak pump power is MANY times higher in a flashlamp setup, therefore they add more Nd3+ to it so it can store and output more energy at once.

It's hard to tell if it's glass or YAG (or something else) based on the photos alone. Plus if you don't know the doping concentration, it makes it very hard to try designing a good pumping scheme for it. The rod is only a fraction of the cost of your total setup for something like this. If you are going to spend the money on optics, energy storage capacitors or laser diode arrays, etc., you might as well get a good rod with known doping and build an optimized laser.

Also, I'm gonna recommend reading this book if you want to build a YAG, ruby, or glass laser. Lots of great info. Hell I may have already recommended it to you before. https://www.ebay.com/itm/Solid-Stat...id=2137676&hash=item3f928a4b1b:i:273041476379

 

[Alaskan]

You are right, forgot it's the other way around for doping, less for CW rods. I had even chimed into to another thread once pointing out CW rods are lower doped, how could I turn that around! Only reason I was interested in this rod is it has mirrors deposited on the ends for HR and OC. I would flash lamp drive this, already have the HV power supply and flash lamps I need, just need a mount and reflector cavity, to get it to produce the best power output.

 

[CurtisOliver]

My fault Chris. I got it backwards. :banghead:
Has not been my day today.
Good explanation though styropyro. Especially for those who want to learn or relearn.

 

[Alaskan]

It happens, even master Cyp. got it backwards in a thread once, the only time I caught him and for that one moment, he bowed to my small sliver of superior knowledge!

I ordered that book, thanks Styro, I will find a way to get it to me in Qatar later.

 

[CurtisOliver]

Lol, been busy with work and that and the weather has drained me tonight.
Anyway, people get things wrong and a bit of humility is always good.

 

[Alaskan]

I think most of us initially think the doping would be higher for a flash lamp pumped rod, simply because the peak energy of the pulse is so high we think the doping needs to be too, but it's the inverse, with a high amount of peak power into the rod, the less dopant is needed, but you already realise you fell into the same hole I did today, and even the laser Jedi master once.

 

[paul1598419]

I've got a newer edition in hardcover. It is an excellent text with a fair amount of math too. I have been reading it since I got it some months ago. It is also a great reference if you need to look something up quickly, but only after you are familiar with it.