Multilayer Q-BIC-like Optical Filters with High Throughput Direct-Write Multilayer Lithography

TL;DR

This paper introduces a high-throughput, scalable fabrication method for multilayer resonant metasurfaces using direct-write electron-beam lithography with antimony sulfide, enabling complex spectral filtering for imaging and spectroscopy.

Contribution

It demonstrates a novel, efficient fabrication platform for multilayer metasurfaces with independently tunable resonances, surpassing previous methods in throughput and spectral control.

Findings

Successfully fabricated three-layer metasurfaces with independent resonance control.

Achieved low correlation coefficients in filter arrays for hyperspectral imaging.

Demonstrated practical applications in compressive sensing and spectral reconstruction.

Abstract

Multilayer metasurfaces provide substantially greater spectral design freedom than single-layer devices, yet their implementation in the visible and near-infrared remains limited by the complexity, cost, and low throughput of conventional nanofabrication. Here, we establish a recently proposed direct-write electron-beam lithography approach as a high-throughput fabrication platform for multilayer resonant metasurfaces, based on an antimony precursor that decomposes in situ into high-index antimony sulfide. This method eliminates deposition-etch cycles and reduces each layer to only two fabrication steps, enabling efficient realization of multilayer architectures. Using this platform, we demonstrate multilayer q-BIC-derived metasurfaces with independently tunable resonance wavelengths and linewidths, allowing the construction of compact multi-resonant filters with spectrally decoupled layers. We experimentally demonstrate three-layer devices supporting three resonances and show independent control of resonance wavelength and Q factor across layers. Leveraging this capability, we generate decorrelated filter arrays for compressive sensing and hyperspectral reconstruction, achieving sets of 9 and 36 filters with average absolute Pearson correlation coefficients of 0.11 and 0.21, surpassing prior metasurface and photonic-crystal implementations. These results establish a practical route toward scalable multilayer resonant metasurfaces for spectral filtering, on-chip spectroscopy, and computational imaging.