Answering viewer questions about refraction

Summary by Krater

This video answers viewer questions about the index of refraction, explaining why slowing down implies bending, what causes birefringence in materials like calcite, why sugar rotates polarized light differently depending on its chirality, and how an index of refraction lower than 1 is possible without violating causality.

From the video

Answers: How can the index of refraction be lower than 1 and what causes birefringence?

• index of refraction
• Snell's law
• birefringence
• chirality in molecules
• phase velocity vs group velocity
• refractive index less than 1

What it concludes

• Slowing down light through a medium implies that wave crests must tilt, which leads to bending as described by Snell's Law.
• Birefringence is caused by crystal structures having different restoring forces and resonant frequencies in different directions.
• Sugar rotates left-handed and right-handed circularly polarized light at different speeds because it is chiral and interacts differently with each polarization.
• An index of refraction lower than 1 occurs when successive layers of a material kick the phase forward, creating the illusion of a wave traveling faster than the speed of light without violating causality.