近日，哈尔滨工业大学徐科团队研究了具有高光谱通道密度的可扩展片上衍射散斑光谱仪。该项研究成果发表在2025年3月20日出版的《光：科学与应用》杂志上。

芯片级集成光谱仪为比传统台式光谱仪更广泛的应用开辟了新的途径。虽然光谱重建应该同时控制光谱分辨率和带宽，但大量的光谱通道是光谱仪设计的关键目标之一。然而，芯片占用最终限制了成熟的光谱到空间映射结构（如色散元件、滤波器阵列、随机介质等）的光谱信道容量。

研究组提出了一种替代方案，即使用片上衍射元表面对光谱信息进行编码。平面内超表面能够产生强度散斑来解析光谱。通过三层级联的元表面缩放架构，光谱丰富度大大增加。散斑的读出通过光栅衍射图案的二维成像来实现，从而能够为光谱重建提供一个大矩阵。光谱仪在100 nm的带宽内具有70 pm的分辨率。在仅150μm×950μm的紧凑芯片面积内获得了多达1400个光谱通道。片上衍射光谱仪的基准通道密度高达10021ch/mm²，与其他最先进的波导结构相比具有优势。

附：英文原文

Title: Scalable on-chip diffractive speckle spectrometer with high spectral channel density

Author: Zhang, Zimeng, Xiao, Shumin, Song, Qinghai, Xu, Ke

Issue&Volume: 2025-03-20

Abstract: The chip-scale integrated spectrometers are opening new avenues for a much wider range of applications than their conventional benchtop counterparts. While spectral reconstruction should be in command of both spectral resolution and bandwidth, a large number of spectral channels is among the key goals of the spectrometer design. However, the chip footprint eventually limits the spectral channel capacities of well-established spectral-to-spatial mapping structures like dispersive elements, filter arrays, random media, and so on. Here we suggest an alternative scheme by encoding the spectral information using on-chip diffractive metasurfaces. The in-plane metasurface is capable of producing intensity speckles to resolve the spectra. The spectral richness is greatly increased by scaling the architecture via three layers of cascaded metasurfaces. The readout of speckles is realized by two-dimensional imaging of the grating-diffracted pattern, enabling a large matrix for spectrum reconstruction. The spectrometer has a resolution of 70pm over a bandwidth of 100nm. Up to 1400 spectral channels were obtained within a compact chip area of only 150μm×950μm. The on-chip diffractive spectrometer has a benchmark channel density of up to 10021 ch/mm2, which compares favorably against other state-of-art waveguide structures.

DOI: 10.1038/s41377-025-01797-y

Source: https://www.nature.com/articles/s41377-025-01797-y