  We systematically investigate the generation of optical chirality patterns by
applying the superposition of two waves in three scenarios, namely plane waves
in free space, evanescent waves of totally reflected light at dielectric
interface and propagating surface plasmon waves on a metallic surface. In each
scenario, the general analytical solution of the optical chirality pattern is
derived for different polarization states and propagating directions of the two
waves. The analytical solutions are verified by numerical simulations.
Spatially structured optical chirality patterns can be generated in all
scenarios if the incident polarization states and propagation directions are
correctly chosen. Optical chirality enhancement can be obtained from the
constructive interference of free-space circularly polarized light or enhanced
evanescent waves of totally reflected light. Surface plasmon waves do not
provide enhanced optical chirality unless the near-field intensity enhancement
is sufficiently high. The structured optical chirality patterns may find
applications in chirality sorting, chiral imaging and circular dichroism
spectroscopy.
