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Largest Commercial Helium Neon Laser In The World (Spectra Physics 125A)

lasingfox

lasingfox

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Joined
May 2, 2020
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84
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18
sooooooo,

I picked this behemoth up for free nearby and I thought i'd share its journey.

It originally came from the university of california and survived the trip in the back of a truck all the way to massachusetts!! some guy was moving out and thought it deserved a good home and I offered to pick it up. it was non lasing a year ago when he tested it but i thought it'd just be misaligned. I picked it up along with a lexel model 75 but that's another story.
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I finally got back to my dorm and gave it a good scrub since it had maybe 50 years worth of dust in it.
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So, after bringing it up to the fourth floor with some help, I powered it up...
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yea.. filled with hydrogen.. soo, i ran it for a few hours in hopes of it cleaning up and then I started to notice a slight color change.
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until suddenly..
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after that cleanup, its up to 88mW!!!!! absolutely insane. and it can also do a ton of 612nm with external optics. i'm working on getting a new OC to tune to orange in normal operation.. did i mention it has a tuning prism?
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Nice safe! Good work!
Time to see some orange photons, gas is still way better than solid state. This is such a nice crisp beam and a cozy space heater too :D
 
lasingfox said:
sooooooo,

I picked this behemoth up for free nearby and I thought i'd share its journey.

It originally came from the university of california and survived the trip in the back of a truck all the way to massachusetts!! some guy was moving out and thought it deserved a good home and I offered to pick it up. it was non lasing a year ago when he tested it but i thought it'd just be misaligned. I picked it up along with a lexel model 75 but that's another story.
image0.jpg

I finally got back to my dorm and gave it a good scrub since it had maybe 50 years worth of dust in it.
clean.jpeg


So, after bringing it up to the fourth floor with some help, I powered it up...
image0.jpg
image0.jpg
image0.jpg

yea.. filled with hydrogen.. soo, i ran it for a few hours in hopes of it cleaning up and then I started to notice a slight color change.
image0.jpg
image0.jpg


until suddenly..
image0.jpg
image0.jpg


after that cleanup, its up to 88mW!!!!! absolutely insane. and it can also do a ton of 612nm with external optics. i'm working on getting a new OC to tune to orange in normal operation.. did i mention it has a tuning prism?
image0.jpg
DSCN1721.JPG
image0.jpg
image0.jpg
image0.jpg
image0.jpg
image0.jpg
Click to expand...
not try and get some 594!
 
That is a very cool find! Biggest russian He-Ne laser could do not more than 70 mW on 632 nm multimode.
 
lasingfox said:
brand new they can do about that with the RF module yea. i'm just amazed its doing almost 90mW after being practically dead to hydrogen.
Click to expand...
where did the hydrogen go, the discharge turned bright orange somehow?
 
The getter absorbed hydrogen. Getter is activated from the heat of the discharge in the laser tube.
 
Great save! Congratulations on getting this for free. And, considering its age......not bad at all. I have 6 HeNe lasers myself. I had been using them since 1980 to make holograms. I thought I might start doing that again, but need a sturdy place to do that as vibrations and air currents will ruin holograms.
 
someone just gave away one of them on the east coast. I just about snagged it, but decided, I don't have the room, or facility to take proper care of it. Those are awesome, but huge lasers. You NEED to run it on a regular basis to keep it happy. Very few of them are running anymore because of that. Glad you were able to bring it back to life.
 
If you ever get I. Trouble with it look up dale@hhr-lasers.com. He has refurb several. Expensive as it needs lots of helium3 which is rare and 2500 a liter plus special neon isotopes. 22 I think.
 
icecruncher said:
someone just gave away one of them on the east coast. I just about snagged it, but decided, I don't have the room, or facility to take proper care of it. Those are awesome, but huge lasers. You NEED to run it on a regular basis to keep it happy. Very few of them are running anymore because of that. Glad you were able to bring it back to life.
Click to expand...
oh don't worry. i plan to run it periodically along with my ions. i'll die before i let this thing die :)
 
I miss mine :-( The last attempt to regas the beast did not go well.
 
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