Post your interesting eBay finds...

[pschlosser]

I made the other offer, at $25.

Rare it may be, but fewer people are seeking, too.
I mean, a Pee-wee Herman lunch box is rare, too, but who wants one?

[SoulFeast]

I don't have a link to the listening, but a couple months ago I was able to snag a working Ohmeda Raman particle counter off of ebay for $125. Still operates in 6 lines, just took some severe gas doctoring to revive a presumably dead soft seal.

[lasersam]

That's the one I bought, or is this another one?

I've still got my 7 line Ohmeda. 604, 612, 629, 633, 635, 640, 650 nm.

--- sam

[SoulFeast]

I wish I had 2

This is the one you doctored....Dr. Sam (pun?).

Forgot that nobody over here really knows me (or at least a small pool). So nobody knows the origin of the Ohmeda. I found it on ebay, and sent a message to Sam, it looked strangely familiar, but I wasn't sure what it was. He told me all about it, and how it was just like the one he had on his FAQ. I could sense a tinge of jealousy in our emails Since we weren't sure of it's operational abilities, I made a deal with him for him to buy it, and I'd send him the money. That way it went straight to him for testing. First run, no dice. After several days of 24/7 operation, we were finally able to get about 1.2mW (I'll have to check my emails). With all 6 lines operational (the 640 was on/off at times). It was then (reluctantly :P) sent to me. There's a whole thread about it over on the other side of the force, but not sure about the rules of posting links to LPF. So I just won't until further guidance.

How's the output on that 604?

I was FINALLY able to separate the 629/633/635 bunch. Using a pair of diffraction glasses, and 2 prisms

I've also finally seen the 640. Probably the dimmest conglomerate of photons I've ever sen O.O

Cannot wait to have the honor of meeting you in person at SELEM. I happily consider you my mentor.

[SoulFeast]

[142laser]

Yes Sam is actually the man. I deal with this every day. I get to bounce all my stupid laser ideas off him but he takes walks to relieve the stress. I am so lucky.

I WANT ONE OF THESE LASERS TOO!!! (thumb sucking etc occurring).

Sam is going to SALEM; I stay home in sunny Fla and try to sell some of our lasers.

So say hi to Sam for me; I want to meet him also...

[SoulFeast]

I've heard a lot about you Phil!

You actually ran up the bid on the Ohmeda I mentioned :P

[lasersam]

There's actually a funny story about that Ohmeda. I had seen it on eBay first and knew it wasn't a Brewster tube so initially wasn't interested. Then SoulFeast emailed me about it and I got thinking - and referring to the Laser FAQ. I had forgotten about its serious multi-line aspects. 6 or 7 stable lines from any normal HeNe is totally unheard of. Phil also saw the auction but since SoulFeast saw it first, I offered him the option of my buying and testing it and then sending it to him essentially for cost. At first the discharge was sickly pink with no lasing at all, but the type of PMS/REO tubes used in the Ohmeda are unique in that they often recover with run time. And sure enough, this one recovered and is actually higher power than my 7 line Ohmeda, and interesting in that the 650 nm Raman line - which is extremely rare in any HeNe - is similar in power to the 633 line or perhaps even more powerful. The 650 nm line is also stable which is not supposed to be possible.

--- sam

[SoulFeast]

I actually did not know that first part!

The 650nm is actually the first to come in, then the ~630 clump, then 612, not sure when 640 makes its entrance however. I neglected it a bit and let it go about a month without firing it, and I watched it's warm-up process, it was like watching a campfire. I've never seen TEM changes so fast, it could be described simultaneously with elegant, and ugly. Very hard to put into words.

My to do list involves getting an optical LPM to test all these HeNe, but it won't do much good with the Ohmeda until I get 2-3 more prisms to split the beams up a bit more.

[lasersam]

With one diffraction grating, you can split the beam into its wavelengths. the *ratio* of power in each wavelength will be the same as in the original beam. So, then by measuring the total power and knowing the ratios, you will then be able to estimate the actual power in each wavelength.

--- sam