Design of an all-dielectric metasurface spectral filter array for compact high-performance reconstructive spectrometry

Abstract Nanophotonic filter array detector array-based microspectrometers have gained significant attention for their compact size, low weight, CMOS compatibility, low cost, and low power consumption, making them ideal for mobile and field-deployable applications. We present a microspectrometer design featuring a Si 3 N 4 two-dimensional-dimerised metasurface spectral filter that exhibits sharp, narrow transmission dips. By tuning the metasurface grating period, we create a filter bank that covers a broad spectral range from 422 nm to 774 nm while maintaining a high transmission contrast ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>&gt;</mml:mo> <mml:mstyle scriptlevel="0"/> <mml:mstyle scriptlevel="0"/> <mml:mn>90</mml:mn> <mml:mi mathvariant="normal">%</mml:mi> </mml:mrow> </mml:math> ) across the band. Unlike traditional bandpass filters, we introduce a bandstop filtering strategy, enhancing sensitivity by transmitting all wavelengths except the resonance wavelength. This approach enables improved signal extraction. Coupled with a spectral reconstruction algorithm, our design achieves high spectral resolution and is capable of detecting unknown signals with ultra-narrow linewidths down to 1.0 nm. Our results pave the way for compact, mass-producible, on-chip spectrometers with strong potential for widespread deployment.