  Chiral fields with large optical chirality are very important in chiral
molecules analysis, sensing and other measurements. Plasmonic nanostructures
have been proposed to realize such super chiral fields for enhancing weak
chiral signals. However, most of them cannot provide uniform chiral near-fields
close to the structures, which makes these nanostructures not so efficient for
applications. Plasmonic helical nanostructures and blocked squares have been
proved to provide uniform chiral near-fields, but structure fabrication is a
challenge. In this paper, we show that very simple plasmonic dimer structures
can provide uniform chiral fields in the gaps with large enhancement of both
near electric fields and chiral fields under linearly polarized light
illumination with polarization off the dimer axis at dipole resonance. An
analytical dipole model is utilized to explain this behavior theoretically. 30
times of volume averaged chiral field enhancement is gotten in the whole gap.
Chiral fields with opposite handedness can be obtained simply by changing the
polarization to the other side of the dimer axis. It is especially useful in
Raman optical activity measurement and chiral sensing of small quantity of
chiral molecule.
