spectra physics 255 exciter and laser

Does the plasma tube light and stay on? Can you increase the current? As usual, more information is needed.

He says it flashes a few times and turns off.

He also says it doesn't lase.

So, there may be more than one problem, or the gas may be contaminated affecting both the operating voltage and the gain.

What color is the discharge when it is on?

Does it match one of these?:

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Hello Sam,

I would have to say the "moderate no output" would be the closest. The professor opened it up to demonstrate optical amplification as part of our laser optics course. He has used this for this purpose for a few years now. He said that on the day we were supposed to see it, he heard a 'pop' and then it stopped working. I found one of the professors in another lab today who has a high voltage scope probe and he is going to check the output voltage from the exciter. He is an electronics type and said it's probably a cap in the power supply. It's vintage. We shall see.

Thanks for the reply Sam,

Joe

Could be, though that would be unusual on a SP-255. The caps are high quality and none are electrolytic.

What is the laser? An SP-124? These may go bad on the shelf since many, if not all, are soft-sealed tubes.

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Are any of these "vintage" he-ne lasers worth anything? I've got an old circa 90s he-ne with pwr sply and everything. I'll have to dig it out to see if it still works and the brand/model.

nb

THATS IT!!! NO MORE CRACK!!! I QUIT!!! I read problem with Spectra-Physics 255 laser and my brain converted it to 265 laser.

To me, vintage is 1960s, maybe 1970s for selected lasers.

You can check eBay or post here for what your late model laser is worth. :)

They are worth something.

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o me, vintage is 1960s, maybe 1970s for selected lasers.

You can check eBay or post here for what your late model laser is worth. :)

They are worth something.

You are right there I think I pay about a penny per pound, and sell them for about 2 cents per pound. :)

"Pat B." wrote in news: snipped-for-privacy@n67g2000cwd.googlegroups.com:

Are you hinting at some quasi magical ability to buy UK lasers and sell them in the US against the current exchange rates? I'm just making this up as I go along, but it would be kind of cool if you had, and did.

Hello Sam,

You were correct. They checked out the power supply today, apparently the electronics prof went to my prof after I talked to him yesterday and they tested the supply. It checked out, so my prof told me when I went to class. He said something about contamination in the cavity, or byproducts forming causing it to malfunction. I don't know what model the laser is. They did this before I arrived for class, so I was a little miffed that I didn't get to watch. Anyway, I don't know if he is going to get a new laser or not. He said you can't buy them like that any more. He's been into lasers since the early 70's. I didn't ask him what he meant about the laser diodes because he started his lecture right away, so I just paid attention and wrote. But I think you are right, he is an old time laser guy, and he is having trouble dealing with how inexpensive the laser pointers and laser diode products are nowadays. He has mentioned it a few times to the class.

What is meant by a soft sealed tube?

Joe

A soft-sealed tube has the mirror basically glued on with Epoxy (well, perhaps TorrSeal or something more exotic than hardware store Epoxy) but it still leaks and outgases. So, over time, these tubes die on the shelf. That time can be anywhere from a year or so to forever, but mostly a few years.

A hard-sealed tube has all joints made either with glass-metal seals or with glass "frit", sort of like solder for glass. When properly made, neither of these leaks on any time scale that matters. Most modern lasers use hard-sealed tubes.

If he wants the laser evaluated, have him contact me.

Sometimes, if the tube can be convinced to stay lit, it will come back at least partially after a few hours.

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Ah, vintage lasers. I once had the open cavity HeNe laser from Bill Rogrod's famous laser modes photo, [W.W. Rigrod, Appl. Phys. Lett. 2 1963 51] the one that's reproduced in many laser texts. I lost track of it in one of my lab moves and it went in to storage. Actually there were two of them side by side, one at 6328 and the other at

1.15 (or 1.5) microns depending on mirrors used. There may be some photos of it in the NYC laser and holography museum.

Those were the days.

Later...

Ron Capik

too many times you have said look into my eyes.. They were just too blood shot!

yeah, I've had a pretty luff rife :)