مشخصات پژوهش

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.