From FAQ: IS LIGHT A WAVE OR A PARTICLE?

[erickalle]

So when a photon encounters a solid, and it can interact with an available phonon mode (i.e. something similar to a resonance condition), this photon can be absorbed by the solid and then converted to heat (it is the energy of these vibrations or phonons that we commonly refer to as heat).

Thanks for the great answers but unfortunately for you, people always want to know more.

We know that phonons greatly alter electrical behaviour of metals at different temperatures.
Why isn’t there a change in behaviour with temperature regarding light properties such as described in the answer.
I’ve never looked through glass at around zero K but I imagine it never becomes opaque at any temperature.

 

[ZapperZ]

Thanks for the great answers but unfortunately for you, people always want to know more.

We know that phonons greatly alter electrical behaviour of metals at different temperatures.
Why isn’t there a change in behaviour with temperature regarding light properties such as described in the answer.
I’ve never looked through glass at around zero K but I imagine it never becomes opaque at any temperature.

Because within the framework of the naive case being described, the phonon density of states are not affected by the temperature of the dielectric. Since the phonon states are the only factor in light propagation through this simple medium, you get no significant difference with change in temperature within any reasonable limits.

This of course does not describe ALL materials since there are always exceptions to the simplest case.

Zz.

 

[astrokreng]

I can explain that the behavior of light and phonons in materials is complex and can be affected by a variety of factors. While it is true that temperature can affect the behavior of phonons and their interactions with light, it is not the only factor at play.

Firstly, it is important to note that the behavior of phonons in materials is primarily determined by the structure and composition of the material itself. This means that even at very low temperatures, the phonons in a material may still be able to interact with and absorb photons, depending on the material's properties.

Additionally, the behavior of light in materials is also influenced by other factors such as the material's density, crystal structure, and chemical composition. These factors can affect how light interacts with the material and how much of it is absorbed.

Furthermore, the temperature at which a material becomes opaque will vary depending on the material itself. For example, glass is transparent at room temperature because its atoms are arranged in a way that allows light to pass through. However, at extremely low temperatures, the atoms in glass may become more rigid and less able to transmit light, making it appear more opaque.

In summary, while temperature can play a role in the behavior of light and phonons in materials, it is not the only determining factor. The overall behavior of light in a material is a complex interplay of various factors, and the exact effects of temperature will vary depending on the material's properties.