  The evanescent waves named as EW1, EW2, EW3 are described in 3 respective
experimental setups: 1) total internal reflection; 2) scattering on an
inhomogeneous planar target; and 3) propagation along a waveguide. Some
interactions are considered between EW2 and the environment. The latter may
include a beam of probing particles and/or the screen on which the EW2 are
formed. Some new properties of EW are described, such as complex energy
eigenvalues in case of a movable screen, and evanescence exchange between the
interacting objects. This reveals the connection between evanescent states and
the Gamow states of the studied system. The 4-momentum exchange between EW2 and
the probe is highly selective and may collapse the superposition of studied
EW2- eigenstates to a single EW-eigenstate of the probing particle. Possible
imprints of EW2 in the far field are briefly discussed and a simple experiment
is suggested for their observation. .
