  In this paper we have discussed theoretical concepts and presented numerical
results of local field enhancement at the core of different assemblages of
metal/dielectric cylindrical nanoinclusions embedded in a linear dielectric
host matrix. The obtained results show that for a composite with metal coated
inclusions there exist two peak values of the enhancement factor at two
different resonant frequencies. The existence of the second maxima becomes more
important for a larger volume fraction of the metal part of the inclusion. For
dielectric coated metal core inclusions and pure metal inclusions there is only
one resonant frequency and one peak value of the enhancement factor. The
enhancement of an electromagnetic wave is promising for the existence of
nonlinear optical phenomena such as optical bistability which is important in
optical communication and in optical computing such as optical switch and
memory elements.
