![]() But of course, they cannot happen concurrently to one photon if that is what you are asking. For example, a beam passing through a container of gas may be reduced to 50% its original intensity, which would mean half of the photons have been scattered/absorbed, and half have been transmitted. A Fast, Easy and Free Bittorrent Client For macOS, Windows and Linux Download v4.0.3 stable Release Notes. These processes can occur at the same time within a material, as ultimately, as I mentioned, there are probabilities attached. Whether it is transmitted or absorbed depends mostly on whether it is close to a "resonant" frequency of the material (this is not the only factor involved though). Whether a beam is scattered or reflected is determined primarily by the wavelength of the light compared to the lattice size or number density of the material. These probabilities are referred to as "cross-sections", and can be calculated from the parameters of the system, and are all quantum-mechanical effects. In a very simplistic sense, you can think of each photon in a beam being reflected, scattered, transmitted or absorbed with a certain probability. Reflection, on the other hand, is the scattering of photons, on a macroscopic Transmission is usually referred to as the absence of any interaction taking place between light and matter. I'm not sure why you think transmission involves absorption. For a beam of many photons, these are all happening simultaneously. Thus, for any single photon, it is either reflected, transmitted, or absorbed (I’m ignoring another category you might call “scattered”). The photon which was absorbed/re-emitted many times and emerges out the back of the material is called “transmitted.” The photon which was absorbed/re-emitted one or more times and emerges in the reflection direction we call “reflected.” forward into the material or in the reflection direction at an interface). The photon can be re-emitted in any direction allowed by the exciting polarization however, due to a coherent interference of waves, you’ll only have a significant probability of finding the photon in one of the classical directions of the beam (i.e. This re-emission is slightly delayed, which delays propagation through the material and results in the material having refractive index $>1$. If the photon was absorbed in such a way that its energy may be quickly transferred to some other excitation (say, through electron-electron scattering to another electron state or through electron-phonon scattering to a lattice vibration), then the photon energy remains in the material, and we call it “absorbed.”Īlternatively, the photon can be absorbed into a “virtual state.” This is a state which coherently re-emits the photon. The difference is in what happens to the energy after it is absorbed, and this is in part determined by how the photon was absorbed. parent viewpoints permitting white light to pass through the sample into an optical spectrometer from Kvant as shown in figure 1 b). It is indeed reasonable to consider absorption, reflection, and transmission all as sequences beginning with absorption of a photon. The other replies may be somewhat confusing.
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