An on-chip reconstruction spectrometer provides a powerful approach for miniaturized and portable applications. Owing to the cross-correlation and line shape of broadband responses, the reconstruction spectrometer exhibits limited resolution and a fixed bandwidth. Here we demonstrate a cascaded nanobeam spectrometer with assistance of a reconstruction algorithm. The transmissions of tunable Fano-enhanced nanobeams (FENs) are of good orthogonality and have improved quality factors. We retrieved a narrowband signal of 0.16 nm linewidth and a dual peak at 0.32 nm distance for resolution characterization. This result breaks the limit of the full width at half maximum for narrowband filter spectrometers. An expanded bandwidth is realized by a three-channel cascaded device, and signal spectra in the 16 nm range are reconstructed successfully. Each FEN unit has an ultra-compact footprint of ${18} \times {18}\;\unicode{x00B5}{\rm m}^2$. In view of the improved performance and flexibility, our concept is an ideal candidate for precise and miniaturized applications.

中文翻译：

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具有高分辨率和可扩展性的级联纳米光束光谱仪

片上重建光谱仪为小型化和便携式应用提供了强大的方法。由于宽带响应的互相关和线形，重建光谱仪表现出有限的分辨率和固定的带宽。在这里，我们在重建算法的帮助下演示了级联纳米光束光谱仪。可调谐 Fano 增强纳米束 (FEN) 的传输具有良好的正交性并具有改进的品质因数。我们检索了 0.16 nm 线宽的窄带信号和 0.32 nm 距离处的双峰，用于分辨率表征。这一结果打破了窄带滤光光谱仪半峰全宽的限制。通过三通道级联器件实现了带宽的扩展，成功重构了16 nm范围内的信号光谱。${18} \times {18}\;\unicode{x00B5}{\rm m}^2$。鉴于改进的性能和灵活性，我们的概念是精确和小型化应用的理想选择。