We propose a new design of composite wavelength-scale amplitude-phase diffraction grating as applied to the displacement Talbot lithography. The grating is composed of a conventional metal amplitude binary mask with superposed dielectric phase steps and provides for manyfold optical contrast enhancement of the integrated 'Talbot carpet' as opposed to the amplitude and phase masks purely. By means of the finite element calculations, we analyze the spatial field structure in the proposed gratings with different geometric ridge shapes and show that due to Mie-type resonances excitation the semielliptical dielectric steps in the combination with metal amplitude mask demonstrate excellent spatial resolution (∼) and highest optical contrast (∼22 dB) of integrated Talbot self-images.
- displacement Talbot lithography
- optical contrast
- subwavelength diffraction grating
- Talbot effect
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics