What precisely IS reflection: what happens at the microscopic level?

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    Microscope Reflection
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Discussion Overview

The discussion revolves around the nature of reflection at the microscopic level, particularly focusing on the interaction of photons and electromagnetic (EM) waves with materials. Participants explore various theoretical frameworks, including quantum mechanics and classical electrodynamics, to understand the processes involved in reflection and refraction, especially in solid-state contexts.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that discussing reflection in terms of photons rather than just EM waves may provide a clearer understanding.
  • There is a proposal that the crystal structure of dielectrics, composed of oscillating dipoles in an E field, plays a crucial role in the reflection process.
  • One participant mentions that the quantum mechanical description of solids is complex and essential for understanding how photons interact with materials.
  • Feynman's lectures are referenced as providing valuable insights into dipole interactions related to reflection, refraction, interference, and diffraction.
  • Another participant notes that the reflection and refraction from metal surfaces depend on plasma frequency, with implications for how light interacts with materials based on its frequency.
  • Classical Electrodynamics by JD Jackson is cited as a resource for a detailed mathematical overview, though some participants question its focus on photons specifically.

Areas of Agreement / Disagreement

Participants express differing views on the best framework for understanding reflection, with some advocating for a photon-centric approach and others emphasizing classical wave descriptions. There is no consensus on the most effective model or explanation.

Contextual Notes

Participants highlight the complexity of quantum mechanical interactions in solids and the varying interpretations of classical electrodynamics, indicating that assumptions about the nature of light and materials may influence the discussion.

henpen
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I post in the QM section as an answer in terms of photons rather than just EM waves would be better.
 
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I think there might be a complicated path integral-like formalism for photons, but a good way of looking at it is with EM waves. The crystal structure of the dielectric is composed of a bunch of dipoles, which oscillate in the E field of the EM wave. And then, an oscillating dipole gives off its own radiation. The values of epsilon in either medium should determine the direction of that radiation in those media.
 
henpen said:
I post in the QM section as an answer in terms of photons rather than just EM waves would be better.

You may want to start by reading this thread:

https://www.physicsforums.com/showthread.php?t=168308

Your question was moved to the solid state forum because I'm assuming that you're asking about specular reflection off ordinary mirrors. Mirrors are typically metal films, and thus, it is a topic in solid state/condensed matter physics. The quantum mechanical picture of optical phenomena in solids is complex and extensive, and it involves just just the photon, but also the quantum mechanical description of the solid itself. This means that the nature of the solid as crucial, since that is what is interacting with the photons.

Zz.
 
As far as I remember, Feynman has a very nice discussion, in terms of dipoles, in Vol. 1 of his lectures. He also discusses refraction, interference and diffraction.
 
Feynman goes into a Non-mathematical explanation in QED (for the layman) of photons reflected off glass surfaces, its a nice read, even if you are mathematically inclined.
 
Classical Electrodynamics by JD Jackson will give you a detailed mathematical overview in terms of photons I believe
 
As someone has already pointed out,that the reflection and refraction from a metal surface depends on plasma frequency.if frequency of light is above the plasma frequency ,it will transmit otherwise it will reflect. Plasmons the quantum excitation of plasma state will explain it.see here
http://en.wikipedia.org/wiki/Plasmon
 
FeynmanIsCool said:
Classical Electrodynamics by JD Jackson will give you a detailed mathematical overview in terms of photons I believe

Have you read Jackson? There is very little in it on photons.
 
Vanadium 50 said:
Have you read Jackson? There is very little in it on photons.

Chapter 7 titled: Plane Electrodynamic Waves, and Wave Propagation. Your right, it deals with relflection and refraction of wave based light, but not photons, so your right Whoops!
 

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