Hyperbolic Secant Graded Index Photonic Crystal Flat Lens for Subwavelength Focusing of Light

Abstract

In this paper, we propose a graded index (GRIN) medium to obtain subwavelength focusing of light in high and low normalized frequency regimes by using all-dielectric materials. Distributed profile of hyperbolic secant GRIN structure is approximated by using two-dimensional (2D) photonics crystals (PCs). The focusing of light is quantitatively and systematically analyzed at low frequencies. It is clearly shown that the efficiency of focusing phenomenon changes as in terms of full-width at half-maximum (FHWM) and focal point distances according to structure length and other important parameters. Light focusing at subwavelength dimension has the capability of achieving unique contributions to lasing, optical imaging and microscopy, nanolithography, data storage and optical precision measurements. Moreover, an experimental verification of the numerical analyses is demonstrated in the microwave regime and corresponding results will be shared in the conference. © 2019 IEEE.