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Re: Wavelength of He-Ne laser

Your question is not at all stupid. What is wrong is that we don't
mention often enough and may "laser pointers" do not explicitly say (I
guess there just isn't enough room on the little cylindrical barrel) that
the light source of the laser pointer is a DIODE. Its relatively small
physical extent (as compared to the light tube of most gas lasers) also
accounts for the shorter coherence length.


On Tue, 13 May 1997, Larry Smith wrote:

Sorry if this is a stupid question, but the textbooks all say the
wavelength of He-Ne lasers is 632.8 nm; so why does my little $25 laser
pointer I carry to lecture say its wavelength is 670 nm?

Thanks in advance,
Larry




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