Strange He-NE? Anybody know?

argon said:

Maybe this is not a Helium-Neon-Laser, but a Helium-Cadmium-Laser. HeCd-Lasers also need a high voltage as HeNes and are similar in several ways...

Greets argon

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Greenmechanic said:

I saw this laser on eBay and wondered if anybody knows exactly what it is. It was listed as a He-Ne. (and

That is a Research Electro Optics (REO) tube rebranded by DATEX-OMeda. The o2 and n2 numbers are for a instrument it was used it, it looked at what the patient breathed out when under anesthetic. It used intra-cavity RAMAN scattering to measure the gases. There is a brewster windowed gas cell in between the hene's brewster, a intracavity prism, and then the high reflector. Yes, both ends had high reflectors, the one I have leaks about 500 uW when running for a reference beam.

If you find a working one, you can pop out the gas cell, realign it, and get the orange and other red lines with the intracavity prism.

In other words its your garden variety external mirror hene tube, albeit a bit higher quality then usual. Your other part in the picture contains four photomultipliers or avalanche photodiodes (depending on model) behind dichroic filters that look at the raman signatures scattering off the intracavity gas. The heatsinking is for stabilty as they heat the internal gas cell to keep water vapor out.

I've never seen a green one, but I gave one like that in the picture, to Sam... I have one on my bench. The N2 (purple) will clean up when ran,, but it really never gets to enough gain to get to 1 mW, let alone 4 once they are purple. If you can get the full assembly, the weak OC coupling will support tuning red through orange but not yellow. You can get yellow with a change of optic. Well, I can, but its a 250$ mirror that is not out there on surplus.

Dead ones have a nice removable and quite rare broadband hene mirror that you can align to even a sealed mirror hene and start seeing other colors (3 mirror cavity, I taught Sam that trick)

That thing in the background the rest of the assembly, the prism is in the AL box with round flange and with the brass hose fittings on it.

Cheers,

Steve

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