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Abstract
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In this work, we have designed tunable narrow band filters using symmetric and asymmetric
one-dimensional plasma photonic crystal structures. Both proposed structures contain a
plasma defect layer that its electron density and therefore the refractive index can be modulated
sinusoidally by an external electric or acoustic fields. The transmittance spectrum is
obtained by using the transfer matrix method. The results have shown that in symmetric
and asymmetric structures, one and two very sharp localized defect mode appears in the
photonic band gap, respectively. The frequency of the defect modes and their transmittance
intensity are studied by changing the amplitude and frequency of the applied external field
to the plasma defect layer. It is observed that by increasing the modulation frequency and
its amplitude, the defect mode frequencies change and shift toward the lower frequencies
that can be introduced as tunable narrow band filters.
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