Snell’s law,
Figure 4.1: Scheme of light, reflected and refracted by a boundary.
Relations between the magnitudes of the incident, reflected and refracted fields are
given by Fresnel equations. We have to distinguish between parallel and perpendicular
polarized light. Parallel or perpendicular polarized means that the electric field is parallel
or perpendicular to the plane of incidence, respectively. For perpendicular polarized light
the Fresnel equations are given by
where the s stands for senkrecht, which is German for perpendicular. The relations for
parallel polarized light are
The intensities are proportional to the square of the electric field, I ∝ ξ
2
. For unpolarized
light, we have to take the mean values of the two polarizations. For the reflectivity R we
thus obtain
For normal incidence this leads to
Because of conservation of energy the sum of R and the transmittance T must be 1,
By combining Eq. (4.14) with (4.16) and doing some calculations we find
Figure 4.1: Scheme of light, reflected and refracted by a boundary.
Relations between the magnitudes of the incident, reflected and refracted fields are
given by Fresnel equations. We have to distinguish between parallel and perpendicular
polarized light. Parallel or perpendicular polarized means that the electric field is parallel
or perpendicular to the plane of incidence, respectively. For perpendicular polarized light
the Fresnel equations are given by
where the s stands for senkrecht, which is German for perpendicular. The relations for
parallel polarized light are
The intensities are proportional to the square of the electric field, I ∝ ξ
2
. For unpolarized
light, we have to take the mean values of the two polarizations. For the reflectivity R we
thus obtain
For normal incidence this leads to
Because of conservation of energy the sum of R and the transmittance T must be 1,
By combining Eq. (4.14) with (4.16) and doing some calculations we find