  We show that, contrary to the common wisdom, surface plasmon poles are not
involved in the imaging process in leakage radiation microscopy. Identifying
the leakage radiation modes directly from a transverse magnetic potential leads
us to reconsider the surface plasmon field and unfold the non-plasmonic
contribution to the image formation. While both contributions interfere in the
imaging process, our analysis reveals that the reassessed plasmonic field
embodies a pole mathematically similar to the usual surface plasmon pole. This
removes a long-standing ambiguity associated with plasmonic signals in leakage
radiation microscopy.
