Xu Hongnan, Qin Yue, Hu Gaolei, Tsang Hon Ki
Department of Electronic Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Nat Commun. 2024 Jan 10;15(1):436. doi: 10.1038/s41467-023-44518-y.
Integrated spectrometers offer the advantages of small sizes and high portability, enabling new applications in industrial development and scientific research. Integrated Fourier-transform spectrometers (FTS) have the potential to realize a high signal-to-noise ratio but typically have a trade-off between the resolution and bandwidth. Here, we propose and demonstrate the concept of the two-dimensional FTS (2D-FTS) to circumvent the trade-off and improve scalability. The core idea is to utilize 2D Fourier transform instead of 1D Fourier transform to rebuild spectra. By combining a tunable FTS and a spatial heterodyne spectrometer, the interferogram becomes a 2D pattern with variations of heating power and arm lengths. All wavelengths are mapped to a cluster of spots in the 2D Fourier map beyond the free-spectral-range limit. At the Rayleigh criterion, the demonstrated resolution is 250 pm over a 200-nm bandwidth. The resolution can be enhanced to 125 pm using the computational method.
集成光谱仪具有体积小、便携性高的优点，可为工业发展和科学研究带来新的应用。集成傅里叶变换光谱仪（FTS）有潜力实现高信噪比，但通常在分辨率和带宽之间存在权衡。在此，我们提出并演示二维FTS（2D-FTS）的概念，以规避这种权衡并提高可扩展性。核心思想是利用二维傅里叶变换而非一维傅里叶变换来重建光谱。通过将可调谐FTS和空间外差光谱仪相结合，干涉图成为具有加热功率和臂长变化的二维图案。所有波长都被映射到二维傅里叶图中超出自由光谱范围极限的一组点上。在瑞利判据下，在200纳米带宽上演示的分辨率为250皮米。使用计算方法可将分辨率提高到125皮米。
