Improvement of the Focusing Resolution of Photonic Crystal Negative Refraction Imaging with a Hollow Component Structure

The negative refraction and imaging effects in photonic crystals can be used to solve diffraction limit problem in near-field optics. Improving transmission efficiency and image resolution is a critical work for negative refraction imaging. We theoretically investigate the band structures, equi-frequency surfaces, electromagnetic wave propagation, and the image intensity distributions in a two-dimensional hexagonal photonic crystal consisting of hollow components. It is found that, in contrast to a hexagonal photonic crystal consisting of solid dielectric cylinders of the same radius, photonic crystals with hollow components can be used to optimize the all-angle negative refraction. Numerical simulations show that the transmission efficiency and resolution of image can be enhanced by changing the radii of the hollow air rods.