PolarizationPolarization In chemistry, we refer to In chemistry, we refer to

polarization as the separation of + polarization as the separation of + and – charges.and – charges.

With light, we are referring to the With light, we are referring to the separation of electromagnetic waves separation of electromagnetic waves whose electric fields are moving at whose electric fields are moving at several different angles. several different angles.

Net electric field is zero – Un-polarized light!

Electric field is moving in one direction – Polarized light!

PolarizationPolarization

When an electric field is only When an electric field is only oscillating up and down or only oscillating up and down or only left and right, it isleft and right, it is linearly linearly polarized.polarized.

How do we make How do we make Polarized Light?Polarized Light?

1. Transmission1. Transmission

2. Scattering2. Scattering

PolarizationPolarization

1. Utilizes “1. Utilizes “polarizerspolarizers” to select for ” to select for a specific electric field orientation. a specific electric field orientation.

TransmissionTransmission

PolarizersPolarizers = long chained = long chained molecules which absorb light with molecules which absorb light with electric fields perpendicular to the electric fields perpendicular to the axis of transmission.axis of transmission.

Multiple polarizing substances can Multiple polarizing substances can be used to determined how linearly be used to determined how linearly polarized light actually is.polarized light actually is.

The greater the angle between the The greater the angle between the electric field waves and the electric field waves and the transmission axis, the less amount transmission axis, the less amount of light will pass through the of light will pass through the second polarizer.second polarizer.

TransmissionTransmission

TransmissionTransmission When the transmission axis (second When the transmission axis (second

polarizer) becomes perpendicular polarizer) becomes perpendicular to the plane of the polarized light, to the plane of the polarized light, no light will pass through.no light will pass through.

ScatteringScattering

Occurs when un-polarized light:Occurs when un-polarized light: a. comes into contact with a. comes into contact with a molecule of a molecule of

atmospheric gasatmospheric gas

b. comes into contact with b. comes into contact with a a

reflective material reflective material

ScatteringScattering

ScatteringScattering

This is how we get This is how we get a glare from roads, a glare from roads, bodies of water, bodies of water, and car hoods.and car hoods.

- Polarizing sun - Polarizing sun glasses whose axis glasses whose axis of transmission is of transmission is perpendicular to perpendicular to the reflected ray the reflected ray will cancel out the will cancel out the reflecting light.reflecting light.