Holographic diffraction grating, see through laser.
Holographic Rainbow Laser Diffraction

 

Code Number: 7G30.10

Demo Title: Wavelengths of a He-Ne Laser

Condition: Good

Principle: Atomic Excitation and Emission from a He-Ne Laser

Area of Study: Modern Physics, Lasers

Equipment: 

Holographic diffraction grating, see through laser.

Procedure:

Set the laser so that the tube is standing straight up and down.  Observe the emission lines of the tube with the grating.  A variety of emission lines should be present in addition to the 632.8 nanometer wavelength emitted by the laser.  In particular note the 543.5 nanometer green line.  (There should also be an infrared line at 1150 nm).  

The approximate mixture of gases in the tube should be 15 % He and 85 % Ne.

References:

  • David W. Steinhaus, "Measurements on the He-Ne Laser Lines Near 633 nm", AJP, Vol. 51, #9, Sep. 1983, p. 824.
  • C. Wong, T. Webb, and C. Londono, "Observation of Wavelength Drift of a He-Ne Laser", AJP, Vol. 48, #4, April 1980, p. 306.
  • J. L. Rapier, H. H. Heimple, and A. L. Schawlow, "Spontaneous Emission from a Helium-Neon Laser as a Convenient Wavelength Standard", AJP, Vol. 35, #9, Sept. 1967, p. 890.
  • John M. Dudley and Goëry Genty, "Supercontinuum Light", Physics Today, Vol. 66, #7, July 2013, p. 29.
  • Frank DeFreitas, Alan Rhody, and Steve Michael,  "Continuous Wave Gas Lasers",  Shoebox Holography - A Step-By-Step Guide To Making Holograms Using Inexpensive Semiconductor Diode Lasers, pp. 39.
  • Gordon McComb,  "He-Ne Colors",  Lasers, Ray Guns, & Light Cannons,  p. 70.
  • T. D. Rossing, C. J. Chiaverina, Light Science, Physics and Visual Arts, p. 139.