Reflection/Absorption in Drude Metals

  • Context: Graduate 
  • Thread starter Thread starter nmbr28albert
  • Start date Start date
  • Tags Tags
    Metals
Click For Summary
SUMMARY

The Drude model of metals indicates that electromagnetic waves cannot propagate at frequencies below the plasma frequency, resulting in an imaginary wavevector and evanescent waves. This leads to perfect reflection of incoming waves; however, real metals like copper and gold exhibit absorption due to interband transitions from the d-band to the conduction band, which occurs below the plasma frequency. Consequently, absorption reduces the reflectivity of these metals, necessitating a reconciliation of reflection and absorption processes in practical applications.

PREREQUISITES
  • Understanding of the Drude model of metals
  • Knowledge of plasma frequency in conductive materials
  • Familiarity with interband transitions in solid-state physics
  • Basic concepts of electromagnetic wave propagation
NEXT STEPS
  • Research the implications of the Drude model on electromagnetic wave behavior in metals
  • Study the effects of interband transitions on optical properties of materials
  • Explore advanced models of metal conductivity beyond the Drude model
  • Investigate experimental methods for measuring reflectivity and absorption in metals
USEFUL FOR

Physicists, materials scientists, and electrical engineers interested in the optical properties of metals and the theoretical foundations of electromagnetic wave interactions with conductive materials.

nmbr28albert
Messages
13
Reaction score
3
One result of the Drude model of metals is that metals cannot sustain an electromagnetic wave for frequencies lower than the plasma frequency - since the wavevector is imaginary the wave will be evanescent and won't propagate. The books I've read say however, that this means the metal will perfectly reflect an incoming wave. None of the books mention absorption of the radiation at this point however. Is absorption not a consideration because there is an evanescent wave then? In real life there should always be some absorption happening though, so how would we reconcile the reflection/absorption processes?
 
Physics news on Phys.org
In the Drude model, absorption only happens in the immediate vicinity of the plasma frequency.
In real life metals, absorption will reduce the reflectivity of the metal, as is the case e.g. in copper or gold where interband transitions from the d-band to the conduction band are present below the plasma frequency.
 
  • Like
Likes   Reactions: nmbr28albert

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
Replies
2
Views
2K
  • · Replies 11 ·
Replies
11
Views
6K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 28 ·
Replies
28
Views
6K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 5 ·
Replies
5
Views
4K