Photonic Crystal Sub-Wavelength lambda/5 Focusing Lens Design Using Optimization Method

Abstract

In this paper, differential evolution (DE) optimization algorithm is applied to design sub-wavelength focusing PCs structure for the first time to the best of our knowledge. For this purpose, the transverse cross section of the input beam is spatially shaped by optimized PC structure. Strong focusing of beam with FWHM equal to lambda/5 and with suppressed magnitude of side lobe intensities is achieved. In addition, microwave experiments to verify the numerical results are conducted. The numerical and experimental results given in the paper are in good agreement with each other.