Fig. 2: Design of ODLM-based CPL filters.
a Schematics of silicon quarter waveplate. U and V are the axes corresponding to the long and short axes of the nanopillars. b Near-field distribution in the middle of the metasurface when the incident polarization is along the length (top) and width (bottom) of the unit cells. c Phase delay difference between the U and V axes (left axis), corresponding transmissions along the V (red) and U (green) axes and total transmission (black) (right axis). d Transmission through the gold nanograting immersed in silicon oxide (left axis) and the corresponding LPER (right axis). e Transmission (left) and CPER (right) of ODLM device. f Wavelength tuning of device by sweeping the length of the silicon nanopillars (and hence the aspect ratio) while all the other parameters are fixed. The length and width of the designed metasurface QWP are 480 and 160 nm, respectively. The thicknesses of the SiOx spacer, Si, and SiOx hard mask layers are 350, 700, and 100 nm, respectively. The nanograting width is 84 nm, and the thickness is 195 nm
