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Homework Help: Laser Cavity Length

  1. Mar 11, 2008 #1
    Hi,

    So I have a lab question for which I have to drive a formula to find the optical cavity length of a laser, [tex] L [/tex]. I have results from testing the fringe patterns when I move one of the mirrors in a Michelson interferometer. It shows the typical [tex] \frac{\sin x}{x} [/tex] pattern. To find the cavity length, I use the distance between two high amplitude peaks, [tex] d[/tex], and the refractive index of the material inside the cavity, silicon in this case so 4.01. What I did was this, since the distance between peaks is the time between a wave has traveled [tex] 2L [/tex], I figured that this formula has to be true:

    [tex] \frac{2Ln}{c} = \frac{d}{c}[/tex]

    which will give me

    [tex] 2Ln = d[/tex]


    Is this accurate?

    Thank you very much in advance.

    Cheers,

    Biest
     
  2. jcsd
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