For accurate measurements, you’ll need an optical instrument such as a monochromator or spectrophotometer or optical spectrum analyzer. But to simply see the complexity of the discharge spectrum inside the bore of a He-Ne laser tube, it’s much easier and cheaper. (Spectra for various elements and compounds can be easily

Continue readingViewing Spectral Lines in Discharge, Other Colours in Output

Putting Together a Demonstration He-Ne Laser For a classroom introduction to lasers, it would be nice to have a safe setup that makes as much as possible visible to the students. Or, you may just want to have a working He-Ne laser on display in your living room! Ideally, this

Continue readingDemonstration He-Ne Lasers, Weatherproofing

Typical He-Ne Tube Specifications Prior to the introduction of the CD player, the red He-Ne laser was by far the most common source of inexpensive coherent light on the planet. The following are some typical physical specifications for a variety of red (632.8 nm) He-Ne tubes (all are single transverse

Continue readingInternal Mirror He-Ne Tubes up to 35 mW – Red and Other Colours

Early Versus Modern He-Ne Lasers In the first He-Ne lasers (see the diagram below), exciting the gas atoms to the higher energy level was accomplished by coupling a radio frequency (RF) source (i.e., a radio transmitter) to the tube via external electrodes. Modern He-Ne lasers almost always operate on a

Continue readingHe-Ne Laser Tubes, Heads, Structure, Power Requirements, Lifetime

There are many uses for even a 1 mW helium-neon laser. Most of these same sorts of things can also be done with a collimated diode laser (though some laser diodes may not have the needed coherence properties for applications like interferometry and hologram generation). Below are just a few

Continue readingApplications of a 1mW Helium-Neon Laser