i]; are the wavevector
of the scattered and the incident photon, and q the wavevector
of the acoustic phonon (Fig.
In the indirect PWE, one formulate wavevector
components of light to be eigenvalues for a given frequency.
It can be easily seen that the incident wavevector
of the electromagnetic field can be tuned to that of the vibration, be it a phonon or the oscillating mode of a macroscopic object, enhancing selectivity and strength of the interaction.
Where k is the wavevector
of the wave, [omega] is its frequency, and A' is its amplitude.
The curve between normalized frequencies and Bloch wavevector
K (called dispersion curve) is shown in Fig.
This concurs with Schrodinger solutions showing a negative energy increase with barrier length, [DELTA]d, while the imaginary eigen-value of the wavevector
[kappa] is constant, independent of barrier length (the Hartman effect)).
However, the development of light-scattering and neutron-scattering techniques showed not only that such relaxation times could be measured with accurateness, but that they were dependent on the wavevector
in such a way that nonlocal effects should be taken into consideration.
i] = (w/c , k), w is the frequency, k is the wavevector
and [PHI] is called the eikonal.
The innovation with respect to standard geometric optics is in the replacement of s with a more general, complex eikonal function [psi] = s + i[phi], where the imaginary wavevector
is perpendicular to the group velocity.
rho]], which is the variable of integration, is the horizontal projection of the wavevector
of an elementary plane wave composing the dipole radiation.
which has a wavevector
, wavelength and angular frequency given by: