It is physically challenging to manufacture a waveplate with a thickness precisely corresponding to a path difference of lambda/2. First, estimate the typical thickness (hint: consider the difference in 'n' for the slow and fast axes). Search and learn how manufacturers circumvent this problem.
We use only 2 boundary conditions in driving Fresnel's laws, whereas Maxwell's equations provided 4 conditions (2 were identical to other 2). What is the intuitive explanation for this redundancy? which boundary conditions turned out to be equivanlent to each other.
All known natural materials have epsilon and mu > 0. However, there is an intense effort to manufacture so-called metamaterials, where both of these are <0. In such a case, given n = sqrt[epsilon x mu], one would take the negative root and n is still a real number, but n <0 why do we take the...