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FrozenGate by Avery

REO Ohmeda Raman Gas Analyzer

How about a single diffraction grating just before a short negative focal length lens, like a concave doublet?
 





I use a reading lens for the divergence, focal length is like 2-3ft which is a PITA when the laser itself is about 3in off the ground. NEED helping hands ASAP. I could try a grating, problem is, the average grating (plastic/film) lets a small out of the output through. A glass mirror grating would be better. I like prisms, but I have too small a room for prisms to work efficiently. They don't spread well since they're so close in the gran scheme of things.

I'll look for a 500-1000line/mm mirror.

This isn't a problem I've face before. There's enough distance between 594/604/612 to allow a good spread. Though I do lose a lot of output. Hopefully with this mirror and my new fog machine, I could get some good beamshots :whistle:
 
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Yes, the main advantage of a diffraction mirror over a transmission grating is that instead of only a small fraction of the output being spread, the entire output is spread.

On my 40mW ML Argon about 28mW gets through completely untouched, it is the other 12mW that gets broken up into 2 to 8 orders, so the split beams are relatively weak.

Bloom, if you find a good source for a 500-100 line/mm mirror clue me in please. I couldn't find anything under $100 for a tiny piece.
 
Just shot that 12mW multimode bare tube I got from cheech226 at my diffraction mirror and got this. Am I looking at 2 lines here or is it just some weird reflection?
 
I looked around for anything in the right ball park. Dave said they range for about $100 on fleebay but you can get lucky and find a cheap one here and there. Will definitely add them to my list of usual fleebay searches.

Speedy, that DOES look orange..curious. Try to put some smoke in the path and see if you notice a difference in color. There are over a dozen RAMAN wavelengths so it's possible it could be any number of them. I'd expect 612 if anything though given the distance way from the main line.
 
T_J...wow, that actually meant a lot to read.. It's nice to hear that from you. Truly. All the talk about me in the past is part of what drives me to be honest. Comparable to an athlete striving to disprove the ones who said otherwise.

Thank you...brother. It's been a pleasure. Email me at any time. :)

Sean
 
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In your opinion, does it look like another color? Does it look orange? Hard to tell via the pics.
 
Its hard to tell with the intensity of the other beam. It shouldnt come out at a dofferent angle if its the sma e wavelength right?
 
Hey Speedy -

I think I recognize that tube. I got it from Dave, and I sold it to cheech. I remember seeing a faint dot often appearing below the primary emission. I always thought it was a back reflection from the HR, which is why the faint dot is always slightly mis-aligned with the bright one. Here's the data for that tube:
LongHeNe.jpg


Its a multi-mode tube - so I'd assume its a "mode gone wild".
 
Ahh ok that makes sense. There is s sort of weak dot around and offset the main dot but then that stargler that clearly comes off at a different angle on my diffraction mirror. Was surprised when I saw that.
 
That would explain why they still seemed like the same color in the beam pics. I didn't know of another way besides it being a separate line. Though the fact that it was MM did stick out. Well I'm glad that's all figure out. Sorry Speedy..
 
Tomorrow I'm going to make a big, comprehensive HeNe/Gas thread for myself with all of my current interesting gas units, as well as all future units and experimentation. Theory is that it'll be a good place to read on info, and get decent pics of some rarely seen wavelengths and lasers. Eventually this will be complimented with a better camera...Any ideas on the camera portion? I also have my new fog machine so some cool beamshots will be taken as well. Girls night out tomorrow so I have all the night to do this. Man time :D
 
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Good idea, Bloom. I've still been unable to get a good picture of the rarer lines from my ML (it does 8 between 458 and 514!) since the individual beam powers are less than 5mW since I'm using a transmission grating, and that is on the first order.
 
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