Conventional phase diffraction gratings can be used to localize the incoming optical radiation in the near-field region. A new design of the binary phase diffraction grating is proposed with embedded pupil opaque mask inside each stripe. By means of numerical simulations, it is shown that with this masked phase grating the spatial resolution of the near-field localization can be substantially improved and brought even beyond the solid immersion limit (λ/2n). Moreover, due to anomalous apodization effect, the subdiffraction field localization is accompanied by intensity enhancement as compared to the non-masked design. The pupil mask rearranges the optical fluxes within the stripes and promotes the Fano resonances excitation in the periodic step lattice. This can be important for advancing the phase grating-based super-resolution technologies, including subdiffraction imaging, interferometry, and surface fabrication.
ASJC Scopus subject areas
- Physics and Astronomy(all)