How does one show that thickness and wavelength determine the full transmission between two different dielectric media if the boundary condition equations between two dielectric media are independent of these quantities?
For example I have a plane wave normally incident on a medium with two layers. The first layer has an index of refraction $n_1$ and is of thickness $d$. The second layer has an index of refraction $n_2$ and is of infinite thickness.
Jackson provides the following boundary condition equations, see page 306
\begin{align} \dfrac{E_0(\text{reflected})}{E_0(\text{incident})} = \dfrac{2n_1}{n_2+n_1} && \dfrac{E_0(\text{transmitted})}{E_0(\text{incident})} = \pm \dfrac{n_2-n_1}{n_2+n_1} \end{align} for normal incidence, which are independent of the wavelength and thickness. What is missing from this analysis? Thanks.