Cool, that's good info, thanks. I have a glass flask of neon and a pyrex manifold for neon tubing but I was under the impression that I needed much more pure stuff. Neon tubes are quite tolerant of contamination relative to lasers. If I can use neon sold for signs and welding grade helium then I'm practically set already, I just need to get my vacuum system back together and give it a go. I picked up a turbopump last year that I need to build a controller for and machine some fittings, once I get that going I can retire the cumbersome diffusion pump and give this a try. I have a few really cool Hughes external mirror HeNe tubes with brewster windows on both ends that Sam G gave me. They have contaminated gas fill so they light up but no hope of lasing, I'd love to reprocess one of them.
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FrozenGate by Avery
Mirrors for SP 125
- Thread starter WizardG
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- May 9, 2011
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Thanks for the info Steve!. 57mW was what I saw the last time I ran the tube; over a year ago. Freshly filled I was getting ~150:yh: My wife and I are in the middle of remodeling our shop and soon I'll finally have a place to set up a proper optics bench for holography.
The last time I messed with holography was almost a decade ago and I can't wait to dive back in. I got the 125 just for it's long coherence length.
The last time I messed with holography was almost a decade ago and I can't wait to dive back in. I got the 125 just for it's long coherence length.
- Joined
- May 9, 2011
- Messages
- 1,219
- Points
- 113
"Where did you get the gas to refill HeNes? I have most of the equipment and considered trying to refill some tubes for the challenge but I hit a wall finding a source of small quantities of the ultra pure gases for a reasonable price."
Go to a neon sign place and you can talk them into a fill for an evacuated flask. If you don't have the glassware you can try filling balloons. If you have good gettering you can afford a little O2 in the bore.
Go to a neon sign place and you can talk them into a fill for an evacuated flask. If you don't have the glassware you can try filling balloons. If you have good gettering you can afford a little O2 in the bore.
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I'll give it a shot after I get my vacuum system set up, I've got a lot of other projects going on that are higher priority. I had no idea the neon for signs was anywhere near pure enough, my recollection is that a few parts per million of certain contaminates would kill lasing entirely. I didn't think welding grade helium was particularly pure but if it is then that's good news, it's gone up a lot but is still fairly cheap.