Rayleigh Scattering: Is Reemitted Light In or Out of Phase?

[stringbean]

I'm just wondering something. Suppose some particles scatter light coming from a monochromatic laser or just some monochromatic light source. I've seen Rayleigh scattering being described as if the particles reemitted light that either added together in phase in the forward direction or was randomly out of phase in the perpendicular direction so that it could possibly cancel out. But what I wanted to know is is this reemitted light in phase with the laser light or 180 degrees out of phase with the laser light in the forward direction. That is in the forward direction does the reemitted light very slightly add to the laser light or very slightly cancel it as you move forward through the material? Thank you.

 

[Valerie Park]

The reemitted light is generally in phase with the incoming laser light, and therefore it adds to the laser light in the forward direction. This is due to the fact that the scattering particles absorb some of the energy from the laser light, then reemit it in the same direction as the incoming wave, so the wave maintains its phase when it's reemitted.

 

[astrokreng]

I can provide an explanation for your question about Rayleigh scattering and the phase of reemitted light. Rayleigh scattering occurs when particles in a medium scatter light in all directions. This scattering can be described as either elastic or inelastic, depending on whether the energy of the scattered light is the same as the incident light. In the case of Rayleigh scattering, the scattered light is of the same energy and wavelength as the incident light, making it an elastic scattering process.

In terms of the phase of the reemitted light, it is important to understand that the particles in the medium are constantly moving and vibrating, which causes the light to be scattered in all directions. This movement and vibration of the particles can result in the reemitted light being slightly out of phase with the incident light. This means that in the forward direction, the reemitted light may either slightly add or slightly cancel the incident light, depending on the specific movement and orientation of the particles at that point.

So, to answer your question, the reemitted light in the forward direction can be both slightly in phase and slightly out of phase with the incident light. It is not a fixed phase relationship, but rather a result of the constantly changing movement and orientation of the particles in the medium. I hope this explanation helps to clarify the concept of Rayleigh scattering for you.