Polarised (polarized) light; EM explanation.

[Roodles01]

Facets of a rock specimen sparkle brightly
In terms of electromagnetism how can I show that a linearly polarised light source can be used to determine that the facets are dielectric rather than metallic?

Should have to do with scattering, but not sure whether it could be explained with a dispersion relation, phase speed of light, or . . . . . .


Is there a simple sketch I could produce to show how?

Help, please.
Thank youi

 

[Simon Bridge]

What is the difference between EM wave interactions with a dielectric vs metal interface?

 

[Roodles01]

When an EM wave encounters a dielectric some of the wave is transmitted & some reflected, as with a metal, too.

When encountering a metal the normal part of the EM wave will absorb a small amount of energy, up to the skin depth, but a dielectric will allow the normal incidence of the wave through as a polarised wave whilst the rest will be reflected.

Hmm!
To me this sounds like if I use linearly polarised light normal to the surface of the facets then measure reflection then there would be less reflection from the dielectric than the metal.

 

[Simon Bridge]

... and you didn't need me after all :)

 

[sardar]

I can provide an explanation for how polarized light can be used to determine the nature of the facets on a rock specimen. Polarized light is a type of light that vibrates in a single plane, rather than in all directions. This can be achieved by passing unpolarized light through a polarizing filter, which only allows light waves vibrating in a specific direction to pass through. When this polarized light interacts with a material, such as a rock specimen, it can provide valuable information about the nature of the material.

In the case of determining if the facets on a rock specimen are dielectric or metallic, we can use the phenomenon of scattering. When polarized light hits a surface, it can be scattered in different directions depending on the properties of the material it encounters. Metallic surfaces tend to reflect light, while dielectric surfaces tend to scatter light in all directions. This can be observed by looking at the brightness and direction of the scattered light.

To demonstrate this, we can use a simple sketch. Imagine a polarized light source, represented by a straight line with arrows indicating the direction of vibration, shining onto a rock specimen with facets. If the facets are metallic, the light will be reflected in a specific direction, and the scattered light will be relatively dim. However, if the facets are dielectric, the polarized light will be scattered in all directions, resulting in a brighter and more diffuse scattered light. This can be seen in the sketch below:

[Insert sketch of polarized light scattering off dielectric and metallic facets]

In addition to scattering, we can also look at the dispersion relation and phase speed of light to further confirm the nature of the facets. The dispersion relation describes how the speed of light changes as it passes through a material, while the phase speed refers to the speed at which the peaks of the light waves travel. Metallic materials tend to have a higher phase speed, while dielectric materials have a lower phase speed. By measuring the dispersion relation and phase speed of the scattered light, we can determine if the facets are dielectric or metallic.

In conclusion, the use of polarized light can provide valuable information about the nature of the facets on a rock specimen. By observing the scattering, dispersion relation, and phase speed of the scattered light, we can determine if the facets are dielectric or metallic. I hope this explanation and sketch have helped clarify the use of polarized light in determining the properties of materials.