The general internal construction of the unstabilised laser heads can be found in U.S. Patent #3,626,323: Thermal Stabilizing Arrangement for a Laser Device. Yeah, I know it has "stabilizing" in the title but don't be fooled! :)
The principles of operation but NOT the internal construction for the Perkin Elmer 5800 stabilized HeNe laser is covered in U.S. Patent #3,793,595: Single Frequency Stabilized Laser.
The is a really old HeNe laser made by Perkin Elmer. It consists of a two-Brewster tube with a heated filament in a laser head enclosure that looks like something out of a James Bond flick. A separate power supply about the size of a PC mini-tower attaches via a fat cable.
This laser head may be very slightly newer than the one above, but also uses a two-Brewster laser tube. It's actually called a "Tooling Laser", so it was probably intended for applications like alignment and positioning in a factory. It uses the more modern 5204 power supply, and as can be seen, it still works. :)
There are actually two filaments in this laser head (and probably the others as well), one being a spare. A jumper inside the power supply is used to select the desired filament, presumably to be changed if the first filament burns out. CAUTION: Do NOT change the jumper on a working laser or randomly mate a laser head to power supply without confirming the jumper setting. If an unused (but good) filament is powered, it will outgas causing the discharge color to change dramatically - probably turning blue at which point lasing will cease abruptly. Doing this accidentally for only a few seconds required several hours of running on the original filament to recover. If continued, it probably would have taken much longer.
This is the later model power supply that runs lsaer heads like the the 5600, above. It's about 1/10 the size and weight of that other monster!
This is a very early model Perkin Elmer HeNe laser power supply. The identify of the mating head is unknown but based on a 1968 brochure, it had a minimum rated output power of 1.0 mW (1.5 mW typical), divergence of 0.8 mR (full angle), and an expected life of 4,000 hours. The cost of the system in 1968 was $295.
The is the laser head HeNe laser made by Perkin Elmer. It consists of a two-Brewster tube with a heated filament in a short squat laser head sealed enclosure. A separate large controller/power supply attaches via a cable the thickness of a garden hose.
