ABSTRACT
In the past 20 years, the possibility of creation of artificial materials
with predefined nontrivial electromagnetic and optical properties
has been investigated actively. Here, photonic crystals, that is,
materials with refractive index changing periodically, are widely
known. This periodicity is achieved by usage of closely packed
dielectric spheres of the size of 200-500 nm (artificial opals) or
dielectric wires of different cross sections. In photonic crystals of
this kind, one can select such refractive indices of nanospheres
and their environment and such a geometry of their disposition,
which provide the band gaps’ occurrence at some frequencies,
where radiation with frequencies falling into the band gaps cannot
propagate (Bykov and Shepelev, 1986; Yablonovitch, 1987; John,
1987; Yablonovitch et al., 1991; Soukoulis, 2001). In particular, an
excited atom situated in a photonic crystal and having an emission
frequency within the band gap will have an infinitely long lifetime. It
is important that for the origin of the band gap in a photonic crystal,
the sizes of spheres (and other inclusions) are to be comparablewith
the radiation wavelength.
