5. Restriction to linear response
all amplitude-like observables scale with
a single, overall amplitude factor
all intensity-like observables scale with this
factor squared
6. Light-matter interaction
Light sees variation in speed of light
Spatial variation in index of refraction
7. Describing wave propagation
Why not solving the wave equation
Problems:
1. often not possible
2. does not give necessarily insight
3. each case has to be done all over again
8. Non-stationary interaction
varying with time: very complicated
all our standard approaches fail unless:
• fully adiabatic
or
• fully diabatic
11. Translational symmetry
If there is no translational symmetry
there is no wavevector
there is no dispersion relation
you only have eigenfunctions,
and you have many of them
12. When is there a wavevector?
effective medium
average over disorder
lattice
asymptotically free space
13. There is a wave vector
From now on:
there is a wavevector
14. There is a wave vector ...
dielectric response
there is a wavevector
there is dispersion
density of states
15. We have translational symmetry
Translational symmetry
full translational symmetry
full translational symmetry after averaging
lattice
16. Stationary
Unless I state explicitly otherwise:
stationary potential
stationary measurement
DC, no pulse, no frequency change, ...
17. Dielectric constant to first order
Objects that can be polarized
polarizability
density
Conclusion:
is a measure for the interaction
30. Delay plays no role
The delay time, or slowness,
plays no direct role
31. Background is dispersive
real part of index of refraction
determined by host
imaginary part of index of refraction
determined by impurities
host scatterers
33. If there is a dispersion relation
Wavevector in the localization
criterion is no problem
You give me a frequency
and I will look the wavevector up in the graph
waveguide, slab, sphere
34. Cross-section?
single scatterer in
waveguide, slab, sphere