1Department of Laser and Optical Engineering, University of Bonab, Bonab, Iran
2Department of Physics, Azarbaijan Shahid Madani University, Tabriz, Iran
چکیده
In this paper, the spectral characteristics of nanocomposite structurally chiral medium (NSCM) which is doped with metal nanoparticles have been studied. This medium consists of silver nanospheres that are irregularly placed inside a structurally chiral material whose dielectric properties can be represented by a resonant effective uniaxial tensor. Here, we optimize the spectrum of the structurally chiral medium by adjusting the nanoparticle size. The dielectric function is an important parameter in the design and optimization of the plasmonic resonances of the nanostructures. This function is different for nanoparticles, depending on shape and size, from the dielectric function of bulk material. In the desired dielectric function, the nanoparticle size factor has been added to the lifetime of the free electron as a waste expression. In the absence of nanoparticles, there is a photonic bandgap (PBG) which is due to the chirality of the structure. The presence of the nanoparticles in the proposed structure has introduced two new bandgaps. The location of these band gaps is near the resonant wavelengths of silver nanoparticles and they are highly dependent on the change in the size of the nanoparticles. The dependence on the size also determines the percentage of the adsorption by nanoparticles. By increasing the radius of nanoparticles, in the reflection and transmission spectra, we see the formation of regular band gaps. We believe that the research presented here would provide the basic results to motivate the fabrication of this NSCM for practical applications in selecting transmission and reflection properties with controlling the size of the nanoparticles plunged in the structure.
