Compare phase change upon reflection from a higher vs. lower index of refraction.
Higher to lower: No phase change. Lower to higher: 180-degree phase change.
Compare constructive vs. destructive interference.
Constructive: Waves in phase, amplitudes add. Destructive: Waves out of phase, amplitudes subtract.
Compare reflection vs. refraction regarding phase change.
Reflection: May cause a phase change, depending on refractive indices. Refraction: Does not cause a phase change.
Define thin film interference.
Interference that occurs when light interacts with a film of thickness comparable to the wavelength of light.
What is 'transmission' in the context of light?
The passage of light through a medium.
Define 'reflection' in the context of light.
The bouncing back of light from a boundary between two media.
What is 'absorption' of light?
The process where light energy is taken in by a medium and converted into other forms of energy, such as heat.
Define 'index of refraction'.
A measure of how much the speed of light is reduced inside a medium compared to its speed in a vacuum.
What is constructive interference?
When two waves are in phase, their amplitudes add to create a larger amplitude.
What is destructive interference?
When two waves are out of phase, their amplitudes subtract, potentially canceling each other out.
Describe the process of thin film interference.
1. Light strikes a thin film. 2. Part of the light is reflected at the first interface. 3. Part of the light is transmitted and reflects at the second interface. 4. The two reflected waves interfere constructively or destructively.
How does an antireflection coating work?
1. A thin film is applied to a surface. 2. The film's thickness is one-quarter of the light's wavelength in the coating. 3. Light reflected from the two surfaces of the coating undergoes destructive interference. 4. Reflection is minimized.
