Miniaturizing a Chip-Scale Spectrometer Using Local Strain Engineering and Total-Variation Regularized Reconstruction
Miniaturizing a Chip-Scale Spectrometer Using Local Strain Engineering and Total-Variation Regularized Reconstruction
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DOI：
10.1021/acs.nanolett.2c02654
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发表时间：
2022-10-12
期刊：
影响因子：
10.8
通讯作者：
Ku，Pei-Cheng
中科院分区：
文献类型：
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作者：
Sarwar，Tuba;Yaras，Can;Ku，Pei-Cheng
介绍了一种基于重构算法的适合于可穿戴应用的薄片级芯片级便携式光谱仪。将局域应变工程技术应用于压缩应变InGaN/GaN多量子阱异质结构中，将16个光谱编码器同时作为光电探测器单片集成在0.16 mm2的芯片面积上。内置的GaN pn结实现了直接的光电流测量。采用全变分正则化和核函数选择的非负最小二乘（NNLS）算法在400 ~ 645 nm波长范围内具有良好的光谱重建性能。光谱峰位和峰间强度比的精度分别为0.97%和10.4%。不使用外部光学元件，如准直光学元件和孔径，通过角度不敏感的光收集结构实现，包括在蓝宝石衬底下制造的锥形背反射器阵列。
A wafer-thin chip-scale portable spectrometer suitable for wearable applications based on a reconstructive algorithm was demonstrated. A total of 16 spectral encoders that simultaneously functioned as photodetectors were monolithically integrated on a chip area of 0.16 mm2by applying local strain engineering in compressively strained InGaN/GaN multiple quantum well heterostructures. The built-in GaN pn junction enabled a direct photocurrent measurement. A non-negative least-squares (NNLS) algorithm with total-variation regularization and a choice of a proper kernel function was shown to deliver a decent spectral reconstruction performance in the wavelength range of 400–645 nm. The accuracies of spectral peak positions and intensity ratios between peaks were found to be 0.97% and 10.4%, respectively. No external optics, such as collimation optics and apertures, were used, enabled by angle-insensitive light-harvesting structures, including an array of cone-shaped backreflectors fabricated on the underside of the sapphire substrate.