A longitudinal shift of the amplified and converted images of a beam f
ocussed in a nonlinear component are determined This shift is related
to a change in the effective wave number in the course of parametric a
mplification. When the gain is considerable, the dependence of this sh
ift on the pump intensity is weak and it does not reduce the resolving
power. It is also shown that an inhomogeneity of the distribution of
the gain over the field of view can be corrected in the second stage o
f an amplifier which amplifies the angular spectrum of the radiation t
ransmitted by the first stage.