My understanding is that the photons are not absorbed and re-emitted. The reason being that absorption and subsequent re-emission (ie the exciting of an atom and subsequent relaxing of the electron via spontaneous emission of a photon) is a random process, in that the photon is emitted in a direction completely uncorrelated to the direction it came in at. This is clearly not what the phenomena of refraction does, this would amount to light being dispersed in the material which is not what we observe.
This problem is actually a lot easier to conceptualise with classical electromagnetic waves. With classical em waves, refraction occurs due to the change in the dielectric constant in the material, which is essentially due to the ability of the molecules in the material to polarise when exposed to an electric field, which kind of "reduces" the effect of the field. Another way to think about it is the molecules in the material are producing their own fields via polarisation in response to the applied field that get summed with the incident wave (simple wave superposition) making it appear to propagate slower. However you want to conceptualise it, mathematically the result is the same, the light appears to propagate more slowly in the medium.
Okay back to photons. Photons aren't classical, but they are waves. Now I'm actually a little shaky on the best way to conceptualise this, and I may be outright wrong since it's been a while since I studied this stuff but I believe we can treat photons exactly as we would treat a classical electromagnetic wave when looking how it behaves as a wave, propagating through space and interacting with other fields. And so all of the above paragraph about em waves applied to photons as well. The only thing we have to keep in mind with photons is that they must come in discrete packets of energy, and they can interact with certain atoms to deposit this energy by exciting an electron in the atom (or more realistically interact with the bulk atom lattice to excite electrons in an essentially continuous band). Except in materials where refraction occurs (ie transparent materials), the bandgap is actually too large to allow this to occur, so absorption is not possible and the photon will not be destroyed, and instead pass through as an electromagnetic wave would.
coldlasercookies t1_j8i0rpp wrote
Reply to Light traveling through a medium that slows it. Does the same photon emerge? by TheGandPTurtle
My understanding is that the photons are not absorbed and re-emitted. The reason being that absorption and subsequent re-emission (ie the exciting of an atom and subsequent relaxing of the electron via spontaneous emission of a photon) is a random process, in that the photon is emitted in a direction completely uncorrelated to the direction it came in at. This is clearly not what the phenomena of refraction does, this would amount to light being dispersed in the material which is not what we observe.
This problem is actually a lot easier to conceptualise with classical electromagnetic waves. With classical em waves, refraction occurs due to the change in the dielectric constant in the material, which is essentially due to the ability of the molecules in the material to polarise when exposed to an electric field, which kind of "reduces" the effect of the field. Another way to think about it is the molecules in the material are producing their own fields via polarisation in response to the applied field that get summed with the incident wave (simple wave superposition) making it appear to propagate slower. However you want to conceptualise it, mathematically the result is the same, the light appears to propagate more slowly in the medium.
Okay back to photons. Photons aren't classical, but they are waves. Now I'm actually a little shaky on the best way to conceptualise this, and I may be outright wrong since it's been a while since I studied this stuff but I believe we can treat photons exactly as we would treat a classical electromagnetic wave when looking how it behaves as a wave, propagating through space and interacting with other fields. And so all of the above paragraph about em waves applied to photons as well. The only thing we have to keep in mind with photons is that they must come in discrete packets of energy, and they can interact with certain atoms to deposit this energy by exciting an electron in the atom (or more realistically interact with the bulk atom lattice to excite electrons in an essentially continuous band). Except in materials where refraction occurs (ie transparent materials), the bandgap is actually too large to allow this to occur, so absorption is not possible and the photon will not be destroyed, and instead pass through as an electromagnetic wave would.