  Transmission properties of one-dimensional lossy photonic crystals composed
of negative and positive refractive index layers with one lossless defect layer
at the center of the crystal are investigated by the characteristic matrix
method. The results show that as the refractive index and thickness of the
defect layer increase the frequency of the defect mode decreases. In addition,
it is shown that the frequency of the defect mode is sensitive to the incidence
angle, polarization and physical properties of the defect layer but it is
insensitive to the small lattice loss factor. The height of the defect mode is
very sensitive to the loss factor, incidence angle, polarization, refractive
index and thickness of the defect layer. It was also shown that the height and
the width of the defect mode are affected by the number of the lattice period
and the loss factor. The results can lead to designing new types of narrow
filter structures and other optical devices.
