Melles Griot Helium Neon Tube extraction.

After about an hour and a half of Dremmel cuts, prying with needle nose, plyers, and cussing, I finally got the tube out of my Melles Griot <5mw HeNe.

This is a project I've been wanting to get around to for a long time...but I was afraid I wouldn't be able to pull off the removal without destroying the tube.
I wanted to be able to see the ionized narrow gas capillary glowing while the HeNe was lasing...I love seeing that orange-red neon spectral line. I managed to nick the OC mirror a bit with the drimmel tool, as it was prone to zip around to the other side of that aluminum pipe at high speeds, but lukily I didn't cause any scratches to appear on the tiny spot where the beam exits.

Here's a picture showing the tube in operation post extraction:

Here's one that shows the weaker beam which actually makes it out of the rear, through the HR mirror:

Here's the abuse I had to heap on that Melles Griot aluminum tube before it would yield the laser head.

Nicely done.  Trust me.  I truly understand the nature of that long, shallow cut in aluminum




Peace,
dave

Dave,

Thank you, then you really understand the frustration I felt. Mine had a bunch of small dots, like little silicone divots on top of the "host", with soft rubber or plastic cushions that anchored the glass head in there surprising tightly. The first dremmel cut was painstakingly tedius, but then when it became clear that the only way I was going to be safe was by making a 2nd cut, I was devastated. Anything for science (and fun) though!

WOW! That lamp you made is truly amazing. I saw the thread when you unveiled it and was most impressed.

I have a question. Are the green mirror sets for HeNe easy to get (read affordable)? I guess you'd need a pair. Is that something you can scrounge from a dead or outgassed tube and then do the alignment yourself. I'd love to have a green Helium Neon, especially if it was one I converted myself from red, with my own two hands. Even just a few mw would be great.

-Brett

Brett Miller said:

Dave,
Thank you, then you really understand the frustration I felt.  Mine had a bunch of small dots, like little silicone divots on top of the "host", with soft rubber or plastic cushions that anchored the glass head in there surprising tightly.  The first dremmel cut was painstakingly tedius, but then when it became clear that the only way I was going to be safe was by making a 2nd cut, I was devastated.  Anything for science (and fun) though!
WOW!  That lamp you made is truly amazing.  I saw the thread when you unveiled it and was most impressed.  
I have a question.  Are the green mirror sets for HeNe easy to get (read affordable)?  I guess you'd need a pair.  Is that something you can scrounge from a dead or outgassed tube and then do the alignment yourself.  I'd love to have a green Helium Neon, especially if it was one I converted myself from red, with my own two hands.  Even just a few mw would be great.
-Brett

Click to expand...

The silicone "dots" are how most HeNe's are secured in the aluminum tube.

The mirrors on most HeNe's are "hard" sealed (read epoxied) directly to the glass of the HeNe tube. If you tried to remove the mirrors that are already there you would break the seal and release the gas. There ARE some that have clear windows and external mirrors or "soft" sealed mirrors, but you don't find those very often. If you want a green HeNe, you pretty much have to buy one.

What are you going to do with your little naked HeNe now?

Peace,
dave

daguin said:

What are you going to do with your little naked HeNe now?

Peace,
dave

Click to expand...

Well, I've had that <5mw Melles Griot for about 3 years or so, and while I used it every now and then, it hasn't seen regular use.  I figured it might be more fun for me uncovered...also, I wanted to try to ionize the gas via an external e-field, such as that of one of my tesla coils (another hobby of mine).  I have spark gap coils, Vacuum tube (833A, 813) coils, and Solid State (MOSFET and IGBT switched) tesla coils.  The Vacuum tube switched and solid state coils have very strong e-fields due to continuous wave operation, which should ionize the gas in the capillary and maybe cause lazing to occur sans power supply.  You would think someone would have tried that by now though, if it were feasible...and they probably have.

Another reason I did it was so that I could access the electrodes easier in the even that I decided to build my own HeNe power supplies, a skill that would be nice to have if I ran across any longer/larger higher powered tubes on ebay, or those sought after orange and green tubes.  If you run across any you don't want to bid on, PM me if you're feeling generous.  Most of the ones I've seen are around 300 dollars for a 3mw yellow tube.  I've personally never seen a green, but lately most of my searching has been regarding green DPSS, red, and blu-ray equipment.

Cheers!

-Brett