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0 votes
2 answers
123 views

Diffraction when the wavefront is not parallel to the plane

I am studying Feynman's chapter on the origin of the index of the refractive index (see this link). If I am not mistaken, what he does is to prove that when a wave enters a medium (modelled as a ...
0 votes
1 answer
47 views

Most generic form of refractive index tensors

The refractive index of a material is in general a $3x3$ tensor (as in the case of birefringent crystals). From literature, it seems that in the case of transparent crystals, this tensor is in general ...
-1 votes
1 answer
78 views

Inconvenience of speed of light in optic fiber

As far as I'm concerned, optic fiber is great in order to transport information quickly using light. Since light needs to undergo total internal reflection every single time it hits the walls of the ...
1 vote
2 answers
72 views

Why total reflection happens at only 1 angle?

The critical angle can be intuitively understood by Snell's law.If the incident medium has a bigger diffraction index than the refracted medium then according to Snell's law the refracted ray will be ...
3 votes
2 answers
3k views

Brewster Angle - what is the polarization state of the transmitted wave?

When unpolarized light is incident at Brewster's angle, what I understand is that the reflected wave is S-polarized. What is the polarization state of the transmitted (refracted) part of the wave?
2 votes
0 answers
27 views

Definition of the displacement field in classical field Lagrangian

In a BSM related paper (in appendix B), the authors use an effective Lagrangian $\mathcal{L}_{EFT}$, and define the following fields: $$ \mathbf{D} = \frac{\partial\mathcal{L}_{EFT}}{\partial\mathbf{E}...
0 votes
1 answer
123 views

Wave propagation in inhomogeneous media

There is a problem I'm trying to solve for some time now and is about the standard (?) approximation that it is made when one tries to solve the Helmholtz equation in inhomogeneous media, that is \...
1 vote
0 answers
32 views

Microscopic model of complex refractive index

In my Electromagnetic Optics class, we tried to reconcile the microscopic (optical) properties of matter with its macroscopic counterparts, and one of the most challenging properties is the (complex) ...
2 votes
2 answers
3k views

Why define relative permittivity and relative permeability?

I am reading something about electomagnetic field and the first introduce the free space permittivity and permeability for the electric field and magnetic field. And later when discussing the field in ...
1 vote
2 answers
74 views

On the (variable?) nature of $\epsilon_0$ and $\mu_0$

In electromagnetism, the electric displacement field D represents the distribution of electric charges in a given medium resulting from the presence of an electric field E. Its relation to ...
3 votes
5 answers
491 views

Variations in Refractive Index of Materials

It's quite a common fact that different types of glass have different refractive indices. Most sites I've found attribute these differences to variations in the 'density' of the glass, which is not ...
3 votes
1 answer
102 views

Can the refractive index of a medium be negative?(<0)

Recently I was asked in a test what would happen if the refractive index of a medium was negative. Is it possible really? The refractive index is the ratio of the speed of light in a vacuum and ...
2 votes
1 answer
883 views

Deriving and gaining intuition for the equation for the index of refraction $n = \sqrt{\mu_r\epsilon_r}$

I've come across the equation in the title. It relates the index of refraction of a substance to the square root of the product of the relative permittivity and the relative permeability at whatever ...
0 votes
0 answers
43 views

How to derive the effective permeability for split ring resonator?

in Pendry's 1999 paper "Magnetism from Conductors and Enhanced Nonlinear Phenomena", he give the formula of effective relative permeability $mu_r$ of split ring resonator (SRR) which is one ...
0 votes
0 answers
31 views

Phase jump at medium border with EM wave

I have been reading a book about electrodynamics and I have stumbled upon the following matter which is, to me , contradictory. When the electromagnetic wave changes medium, it is subject to certain ...

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