Silicon Carbide Metasurfaces by Two-Photon Polymerization Gray Scale Lithography

Dielectric nanostructures are used in photonic applications, such as sensing, wavefront manipulation, light detection, and quantum computing. Traditionally, two-dimensional structures are fabricated by patterning and etching a dielectric substrate using standard photolithography or electron beam lithography (EBL) methods. While these well-established methods are powerful, limitations such as their mask requirement, resolution limit, and limitations to create beyond two-dimensional patterns hinders their use. To overcome these challenges, we explore the fabrication of grayscale masks using two-photon polymerization using a Photonic Professional GT2 Nanoscribe 3D printer. We combine this digital laser writing (DLW) technology, and reactive ion etching (RIE). Using this maskless laser-writing technique, the Nanoscribe is capable of writing 2.5-dimensional polymer structures that can be etched to the substrate to create metasurfaces of different shapes, several lateral sizes, and varied heights. This fabrication technique enables the production of one-dimensional and two-dimensional periodic and aperiodic gratings. The quality of these structures is explored optically through infrared reflectivity using a Fourier Transform infrared (FTIR) spectrometer equipped with an infrared microscope as well as Raman scattering mapping. Our results are compared to COMSOL models of the achieved nanostructures.