My DIY orange laser

Here I'd like to share my experience of building a real orange laser! this is a pulsed laser, that uses pure neon as a lasing medium. As far as we know, pure neon can lase only at one IR line in CW mode, mixing it with helium is needed to get visible output. Red he-ne lasers are the most widespread, he-ne of other colours are much more rare, their gain and output power are low. But everything changes when you apply high voltage very short pulses to the tube with pure neon. It begins to lase at various wavelengthes including red (626 nm), orange (614, 594 nm) and green (540 nm)!! Moreover, lasing is superradiant without any mirrors, because gain is extremely high! On the other hand, output pulses are very short (approximately 1 ns), pulse energy is quite low too. Anyway, the simplicity of the laser motivated me to try to make one. I had a broken LE Nitrogen laser tube and brought it to the local neon sign shop. I asked the glassblower to fill it with pure neon at the pressure of 1 Torr or somewhat lower. The appendix on the tube is the getter, to burn the crud out from the gas. Then I installed this rebuilt tube into the nitrogen laser frame, removed the mirrors and attached it to the nitrogen laser supply. And it works! The lasing line is 614 nm, as it is the strongest one according to russian literature. When I split the beam with the diffraction grating I didn't find any other lines. Lasing is superrardiant, adding mirrors doesn't affect performance. The high voltage pulse should be shorter, on the PSU with "fresher" thyratron lasing was more stable and brighter.

Here is the video from youtube: https://youtu.be/42HIzaLnx40

According to the same literature it is worth trying to fill with neon old long (at least 1 meter) He-Ne tube as it can give good lasing at green 540 nm line. Only after building this unit I found Mark Csele's article about building a neon laser from small he-ne tube.

And here are some photos of my setup.

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