Polarization of Light: Filters, Reflection, Scattering, and Materials

All flashcards

Transverse electromagnetic wave

A wave whose electric and magnetic fields oscillate perpendicular to its direction of travel.

Partially polarized reflected light

Reflected light with a preferred polarization direction but also other polarization components.

Brewster angle

The incidence angle at which reflected light is completely polarized.

Optical activity

The rotation of the plane of polarization as light passes through a substance.

Birefringence

Different refractive indices for light polarized in perpendicular directions.

Quiz questions

1. For light traveling from a medium with refractive index $n_1$ into a material with refractive index $n_2$, which equation gives Brewster’s angle $\theta_b$?Answer: $\tan\theta_b=n_2/n_1$
2. Why can polarizing sunglasses reduce glare reflected from water or glass?Answer: They block more of the reflected light’s dominant polarization direction.
3. When an observer views light scattered by air from a direction perpendicular to the original ray, what is generally true?Answer: The observed scattered light is strongly polarized.
4. How can applying voltage to a liquid-crystal cell change the light reaching a viewer in an LCD?Answer: It changes the molecular arrangement and therefore the cell’s effect on polarization.
5. How does a birefringent crystal differ from a dichroic polarizer?Answer: It separates perpendicular polarizations through different refraction rather than selective absorption.