Question

phase shift question

Answer 1

A lightwave travels from point A to B in a vacuum. Suppose we introduce into its path a flast glass plate \(n_g=1.50\) of thickness L=1.00mm. What is the phase shift introduced by the plate?

Answer 2

So I know that the number of wavelengths without the glass is \[N=\frac{d}{\lambda_0}\]and with the glass is
\[N'=\frac{d-L}{\lambda}\]where \(d=\overline{AB}\)

Answer 3

so the difference in number of waves, \(D\), is\[D=L\left(\frac{1}{\lambda}-\frac{1}{\lambda_0}\right)\]

Answer 4

I'm lost from here.

Answer 5

ok I guess I could say \[D=L\left(\frac{n-1}{\lambda_0}\right)\]

Answer 6

To work out the phase shift, you need to know the wavelength of your wave in a vacuum.

L(n-1) is the difference in optical path.
It is to \(\lambda_o\) what your phase shift is to \(2\pi\).

So the answer is \(\Delta \phi=2\pi L(n-1)/\lambda_o\) radians

Answer 7

thanks!