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Nice New Large HeNe

diachi said:
Nice HeNe! Tubes looks stunning, everything looks to be in a good condition too! How much did that run you? :p


I can see the Compass I sold you in the background :D
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Yap! Thanks :) It works great! I actually realized that it was in the box Jason sent it to you in! I traded this to Jason a while back :P
 





Actually, the magnets are there to surpress the superradiant IR lines by using the zeeman splitting of those lines to reduce the gain of them. Polarization is probably guaranteed by brewster angle windows. But compressing the plasma? with magnets on 1 side?
 
Polarization, probably ..... these tubes was usually stated as TEM00 non polarized units, IIRC ..... and the magnets are not just on one side ..... in the piece that is visible yes, but in my unit they are on both the sides of the L-shaped support (means, side and bottom of the tube), around the central part of the tube .....
 
the polarization is guaranteed by the brewster windows, there would be absolutely no way any amount of magnets would make it any better. I have a spectra physics sp-120, and here the magnets are only below the bore. The magnets are there to surpress the IR lines. Nothing to do with polarization of plasma stuff.
 
The magnetism can make it difficult for the longer wavelengths to lase.

Believe it or not, the highest gain in a HeNe is not 632.8nm, it is around 1.5um.

I was wrong on the magnets, I was thinking of an argon laser.
 
And in an argon laser, the magnets are around the tube, not just on one or two sides.
 
Laser_Ben said:
The magnetism can make it difficult for the longer wavelengths to lase.

Believe it or not, the highest gain in a HeNe is not 632.8nm, it is around 1.5um.

I was wrong on the magnets, I was thinking of an argon laser.
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Hate to nitpick, but the highest gain line is 3.39 uM, even a short bar code tube has to have mirrors coated to kill it. It will lase off a first surface AL mirror and your reflective fingernail. The Zeeman splitting is what kills it and a bit of the 1.5 uM line.

Too much Zeeman will kill the the red as well. That is why they use the cheap fridge magnets. If you have a red unpolarized hene tube, you can use weak magnets to favor a polarization.


Steve
 
Can you take a picture with the cover off the head? This laser is really epic long :)
 
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