He-Ne Laser

A helium-neon laser is a gas laser, consisting of a mixture of helium and neon gas in a ratio between 5:1 and 20:1 bound in a glass tube. The pump energy of the laser is provided by an electrical discharge of several hundred Volts between an anode and cathode at each end of theglass tube. A current of 5 to 100 mA is typical for continuous wave operation. The used He-Ne tube has Brewster's angle windows at both ends. The He-Ne laser can work at different wavelengths. There are infrared emissions at 3.39 µm and 1.15 µm and different emissions in the visibles pectrum. Normally, a He-Ne laser is working at the red 632.816 nm wavelength with a very narrow gain bandwidth of a few GHz, which is dominated by Doppler broadening.

Further content and detailed descriptions are available to enrolled students via the course's page at the Moodle website of the Friedrich Schiller University Jena.