ENHANCED IMAGE RESOLUTION IN PHOTONIC CRYSTAL STRUCTURE BY MODIFICATION OF THE SURFACE STRUCTURE

Abstract

Photonic crystals are inhomogeneous dielectric media with periodic variation of the refractive index. A photonic crystal gives us new tools for the manipulation of photons and thus has received great interests in a variety of fields. Photonic crystals also have applications in imaging. A number of imaging principles were demonstrated. In this thesis we focused,enhance the image resolution of photonic crystal by modification the surface structure and used the structure as a sensor. We utilize the superlens behaviour of the photonic crystal (PhC) structure composed of hexagonal lattice arrangement of air holes of radius ‘r = 0.35a’, where ‘a’ is the lattice constant, in a dielectric medium of permittivity ε = 12.The equal frequency contour (EFC) analysis done using plane wave expansion method shows that the structure exhibits an effective isotropic refractive index, neff = -1 at a normalized frequency of ɷ = 0.2908(2πc/a) for TM polarization, located in the second band. At ɷ = 0.2908(2πc/a) for TM polarization, the considered PhC structure behaves as a superlens, as analyzed using the finite difference time domain (FDTD) method.