A gas discharge laser in a sealed glass tube, emitting a clean TEM00 beam at 632.8 nm with powers from under 1 mW to a few tens of mW. Its stable, visible output makes it the standard for aligning invisible beam paths, interferometry and calibration, and optical flatness specs are quoted at its line. Lab people pronounce it hee-nee, and green, yellow and infrared versions also exist.
Co-align the HeNe with the IR through both irises, then we can do the rest of the cavity with the lights on.
Also heard as
- helium-neon laser
- He-Ne
- hee-nee
Related terms
Walk the beam
To align a beam onto a path using two steering mirrors adjusted in turn against two targets or irises.
Coherence length
The path difference over which a light source keeps a fixed phase relationship and can still form interference fringes.
Lambda over ten
Shorthand for an optic flat to one tenth of a wavelength, used to mean good-quality laser optics.
TEM00
The fundamental transverse mode of a laser: a single round spot with a Gaussian intensity profile.