Multi-band reprogrammable phase-change metasurface spectral filters for on-chip spectrometers

Area of Science:

• Photonics and Nanotechnology
• Optical Metasurfaces
• Spectroscopy

Background:

• Active optical metasurfaces enable dynamic light manipulation but often lack wide tuning range and narrow resonance.
• Existing technologies limit advancements in high-precision sensing and detection.
• The need for compact, high-resolution spectrometers is critical for various applications.

Purpose of the Study:

• To propose and demonstrate a reprogrammable active metasurface for on-chip spectroscopy.
• To achieve simultaneous wide wavelength tuning and narrow resonance peaks.
• To enable high-fidelity spectral reconstruction with a single nanostructure.

Main Methods:

• Utilized Germanium-Antimony-Tellurium (Ge$_{2}$Sb$_{2}$Te$_{5}$) as a non-volatile phase change material.
• Designed active metasurfaces supporting magnetic modes and Friedrich-Wintgen quasi bound states in the continuum.
• Investigated coupling phenomena and resonance modes numerically.
• Employed metasurfaces as tunable filters combined with compressive sensing algorithms.

Main Results:

• Demonstrated multi-resonant near-perfect absorption and multilevel tuning in the infrared band.
• Achieved high-fidelity spectral signal reconstruction (>0.99) with only 51 measurements.
• Predicted a spectral resolution of 0.5 nm at 2.538 µm by tuning Ge$_{2}$Sb$_{2}$Te$_{5}$ crystallization.

Conclusions:

• The developed reprogrammable active metasurface offers a promising platform for advanced on-chip spectrometers.
• This technology has significant potential for on-site matter inspection and point-of-care testing.
• The combination of metasurfaces and compressive sensing provides a novel approach for high-resolution spectral analysis.