  Investigation of electronic waves with high coherence in photodetachment of a
negative ion gives a physical basis to develop the holographic electronic
microscopy with high resolution. The interference pattern is considered in the
framework of steady-state wave approach. In semiclassical approximation, an
outgoing wave is described by the amplitude slowly varying along a trajectory.
Quantum description of electron photodetachment from negative ion is formulated
with the help of the inhomogeneous Schr\"odinger equation. Its asymptotic
solution is expressed in terms of the Green function that has exact expression
for the homogeneous electric field and the Coulomb field. It is demonstrated
that repulsive Coulomb field is effective for magnification of the interference
pattern at a short distance from an ion. For the first time, as shown for this
case, the interference pattern in asymptotic area can be calculated by means of
global semiclassical approximation or, a little more roughly, by simple uniform
field approximation. New proposals and possible parameters for experimental
measurement scheme for the effect are discussed.
