light:What are the other important theories of light?

What are the other important theories of light?
 In 1678, Dutch physicist Christiaan Huygens stated that light is made up of waves vibrating up and down, perpendicular to the direction in which the light is travelling. Huygens' Theory is called the Wave Front Theory. Huygens disagreed with Newton, and said that light traveling from air to water will decrease in speed, and vice versa. Later, Huygens was proved to be correct. In the 19th century,James Maxwell put forward the Electromagnetic Theory of Light. According to this theory, light waves are a part of a larger family of electromagnetic waves, and make up the electromagnetic spectrum. The 20th century ushered in the Quantum Theory put forward by Max Planck, a German scientist. It stated that light waves travel as separate packets of energy called quanta or photons, and it is this theory that is widely accepted today.