Waveguide Design at Infrared Wavelength With Asymmetric Dielectric Surface Gratings

In this paper, we propose waveguide design at infrared wavelength with asymmetric dielectric surface gratings. Surface gratings are able to generate the surface plasmon polariton effect at the outlet of radiated light through an aperture. The property and the shape of gratings are key factors behind generating collimated beams from subwavelength slits or holes surrounded by corrugated surfaces. Grating design is conducted by structural optimization based on the phase field method. The design objective is set to maximize the Poynting vector in the measuring area, and it is focused on finding a clear shape of grating structure for the manufacturing feasibility to be taken into account. The simulation and optimization process is performed by using the commercial package COMSOL associated with the MATLAB programming.