  A new approach to the inverse scattering problem proposed by Schroer, is
applied to two-dimensional integrable quantum field theories. For any
two-particle S-matrix S_2 which is analytic in the physical sheet, quantum
fields are constructed which are localizable in wedge-shaped regions of
Minkowski space and whose two-particle scattering is described by the given
S_2. These fields are polarization-free in the sense that they create
one-particle states from the vacuum without polarization clouds. Thus they
provide examples of temperate polarization-free generators in the presence of
non-trivial interaction.
