Rapid Prototyping of Reflective Beam-Steering Metasurfaces with the Plasmonic Phase-Change Material In3SbTe2

Metasurfaces have evolved as prime candidates for miniaturized optical components to tailor the light–matter interaction. Conventionally, the fabrication and design of such metasurfaces with complex antenna structures are well-developed and precise but need clean-room access and multiple fabrication steps. While metasurfaces based on polarization conversion are limited to low efficiencies, metasurfaces with antennas above a metallic mirror reach much higher efficiencies by keeping the initial polarization. Here, we showcase rapid prototyping of reflective beam-steering metasurfaces to optimize their efficiency. We exploit the nonvolatile insulator-to-metal transition of the infrared plasmonic phase-change material In3SbTe2 (IST). Via direct laser writing, we optically program reflective beam-steering metasurfaces with grating strips of varied width into thin IST layers and measure the anomalous reflection at a wavelength of 8.6 μm. Reconfiguring the grating bar widths and hence the covered phase range within the supercell leads to improved anomalous reflections of up to 75%. Our work enables reconfigurable, high-efficiency metasurfaces in the infrared range.