Abstract.
The features
of propagation
of
broadband
signals through photonic crystals are studied. The spectrum of
broadband signals corresponds to both allowed and forbidden frequency
ranges
for the transmission of radiation in the crystal.
For this purpose by finite differences time domain (FDTD) method the
propagation of single Gaussian pulses of different spectral content
through the photon crystal representing the two-dimensional square
grid formed by the cylindrical GaAs elements is investigated. It is
shown that such structure possesses the single complete forbidden band
at rather small density of compositing of elements. Two types of
pulses are analyzed. The first one is formed by electromagnetic
oscillations with a frequency corresponding to the first allowed zone.
The second one was excited at a frequency of the forbidden band. The
time diagrams received in different points inside and outside the
crystal, and patterns of space distribution of a field in it in
different time points are analyzed. The considerable reduction of
velocity of propagation of the signals formed by oscillations with the
forbidden band frequency compared with velocity of light in the
environment is found. As a result of the research the possibility of
localization of a pulse radiation in a photon crystal of the finite
sizes is proved.
Keywords:
photonic crystals,
Gaussian pulses, band
gaps,
localization.
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