Quantum Mechanics Explains Refraction of Light Through Glass

[Zak]

There have been many posts requesting a quantum mechanical explanation for the refraction of light through glass, but none of them (as far as I'm aware) explain why higher frequency light refracts more than lower frequency. Can anybody explain why?

 

[acegikmoqsuwy]

It's probably because the refractive index of the substance is different for different wavelengths of light since the velocity of light is going to be different in separate mediums. It is safe to assume that violet light will be faster in a medium than red light will be in the same medium. If we then look at Snell's law, \displaystyle\frac{\sin(\theta_1)} {\sin(\theta_2)} = \frac{v_1} {v_2} = \frac{n_2} {n_1} It is easy to notice that a small change in v_1 or v_2 will noticeably affect the angles.

The change in the speed of each frequency is due to the material that it's traveling through, and how it vibrates the material.

 

[Jilang]

You might consider how the photon takes many different paths and how these paths interfere with each other based on their relative phase angle. These will be related to the energy and frequency of the photon.

 

[Zak]

Ah, I think then I will have to learn more about Quantum Mechanics to really even appreciate the question. Thanks

 

[jaydnul]

The Feynman QED lectures might help you gain insight.

http://youtube.com/watch?v=LPDP_8X5Hug