Restoration of the NEC GLG-3023 Argon ion laser head

Science fiction from the '70s and '80s was literally obsessed with these kinds of devices. Apart from their obvious scientific importance, back in the day the laboratory experiments with laser light were quite spectacular. Gas lasers in the visible spectrum employing an open bulb tube will most certainly remain as one of the top SciFi motives for long, with that pleasant retro note. Scenes from the Alien (1979) movie, when John Hurt descends to the pit full of xenomorph eggs, were recorded with the help of the frosty blue argon laser light. A similar special effect was used at the beginning of the Aliens (1986) movie, for the scanner investigating the shuttle with Sigourney Weaver on board.

The time of these old fashioned devices has passed, they were largely replaced by the more efficient solid state devices, an inevitable improvement in practicality, but at the same time a big step back in style. Unfortunately as time passes, more and more technically interesting devices are being transformed to "featureless black boxes". But there is also an army of sentimental junkyard scavengers, fighting against this trend by salvaging precious technical artefacts from scrapped equipment and bringing them back to life.

And this is how I found this device, in of my regular surveys of Belgrade's cyber junkyards. I cast everything from my rich bartering spellbook and got it really cheap. The head was incomplete, both the cover and the power supply were missing. It also looked pretty battered, and the prism mount was dismantled and damaged. It seemed that it will end up as just an awkward decoration item. But not on my laboratory's watch, this thing simply had to be brought back to life :)

Technical notes

This laser head employs an integral wavelength selection prism that can be tuned for a selected line. It took a lot of effort to align it with the OC mirror and persuade the tube to start lasing. In the overall absence of online manuals for alignment of such systems, I compiled an instruction manual outlining the procedure I developed and used. Hope that somebody finds it useful:

Resonator alignment of a small argon laser with internal mirrors and a wavelength selection prism

The head after cleaning up the dust and dirtInitial high voltage test of the tube, showing promising signsTube filament powered upArgon plasma glow, stable anode currentA view of the bore where laser magic is supposed to happenTube filament surrounded by the blazing argon plasmaWavelength selection prism after repairsThe OC mirror on the anode sideMy old He-Ne laser on the platform of an old theodolite, prepared as an alignment toolThe first flash of laser light after a lengthy resonator alignment procedure488nm blue argon laser beam488nm blue argon laser beamHe-Ne laser plasmaHe-Ne laser plasmaHe-Ne laser plasmaAll three of my lasers together, argon, He-Ne, and green DPSSThese are the 4 major argon lines: 514.5nm, 496.5nm, 488.0nm and 476.5nm