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Abstract
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Reshaping of a Gaussian light beam with a microcavity type one-dimensional
photonic crystal is reported. We developed the transfer matrix method to
perform our numerical and analytical studies. The considered photonic crystal
consists of a structure as (TiO2/SiO2)5/TiO2/(SiO2/TiO2)5, in which all layers,
except than the central TiO2 layer, have quarter-wavelength optical thicknesses.
The thickness of the central layer is set in a manner to create the resonance
mode in our desirable design wavelength. Our investigations showed that the
radial dependent photonic band gap, and a defect mode are created in the
transmittance spectra of the structure. The physical reason for this effect lies in
the radial phase of the Gaussian light beam, which produces the phase
difference between the rays traveling in the center of the beam and the outer
ones. Analyzing all results revealed that, when a Gaussian beam is normally
incident into the photonic crystal, its intensity profile at the exit plane of the
structure is reshaped.
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