Short-wave infrared (SWIR) spectrometer has been a critical device in spectral analysis fields like agriculture, [1,2] environmental monitoring, [3] astronomy, [4,5] etc. Conventionally, the infrared spectrometer is bulky and delicate due to the spectral division device, such as grating and prism, which limited its applications. The demand and potential for compact spectrometers are enormous for portable and on-chip applications like smartphone spectrometer, [6,7] hyperspectral imaging, [8][9][10] etc. The key to miniaturizing spectrometers is replacing the bulky spectral split devices with miniature photonic devices. [11] Besides, combing with reconstruction algorithms such as compressed sensing and machine learning, the incident light spectrum can be reconstructed with a few numbers of filters. [8,[12][13][14] In recent years, such reconstructive micospectrometer based on Si-based complementary metal-oxide-semiconductor (CMOS) sensors in visible range are primarily investigated. In comparison, the microspectrometer in SWIR range is much more useful to acquire object information in practical applications. Strategies based on photonic devices slab, [9,10,[15][16][17][18][19] quantum dot (QD) slab, [20][21][22] nanowire, [23,24] have been proposed for portable and on-chip microspectrometer. The number and variety of filter spectra determined the resolution of reconstructive microspectrometer. Micro-nano photonic device filters like photonic crystal (PC), metamaterial, Fabry-Perot (FP) cavities can acquire distinctive spectra by varying structure morphology parameters. Material-based filters like QD slab can acquire different spectra by adjusting their size, composition, or bias. Those filters mentioned above are usually fabricated onto a separated slab and then pasted or bonded with a detector chip. In practical applications, the separated slab is fragile and difficult to well-matching with detector pixels, leading to spectral crosstalk and other problems. Recently proposed detector-only reconstructive microspectrometer based on nanowires, [23,24] black phosphorus [25] is ultra-compact without external filters. It has a stable structure with wavelength scale size, but the number of response spectra is hard to increase significantly and limits its resolution.Among these micro-nano filters, FP microcavities array has low spectral correlation coefficient by varying its cavity length, Short-wave infrared (SWIR) information is critical for material analysis, imaging sensing, and other fields. To acquire SWIR spectrum with compact devices, strategies for reconstructive microspectrometer have emerged, such as photonic crystal and quantum dot filter. However, the current SWIR microspectrometer needs many filters with insufficient resolution. In this work, the authors develop a SWIR chip-spectrometer based on Fabry-Perot microcavities array which can be fabricated by using fast and low-cost UV laser directwriting grayscale lithography. The ultra-compact chip-spectrometer can work in a very wide range from 900 to 1700 nm wi...

Reconstructive micro-spectrometers have shown great potential in many fields such as medicine, agriculture, and astronomy. However, the performance of these spectrometers is seriously limited by the spectral varieties of response pixels and anti-noise ability of reconstruction algorithms. In this work, we propose a spectral reconstruction (SR) algorithm, whose anti-noise ability is at least four times better than the current algorithms. A micro-spectrometer is realized by fabricating a large number of Fabry–Perot (FP) micro-filters onto a cheap complementary metal-oxide semiconductor (CMOS) chip for demonstration by using a very high-efficiency technology of nano-imprinting. Nano-imprint technology can complete hundreds of spectral pixels with rich spectral features at one time and with low cost. In cooperation with the SR algorithm, such a micro-spectrometer can have a spectral resolution as high as 3 nm with much lower angular sensitivity than a photonic crystal-based micro-spectrometer. It can obtain the target's spectrum from only a single shot, which has wide applications in spectral analysis etc.

Micro-spectrometers have great potential in various fields such as medicine, agriculture, and aerospace. In this work, a quantum-dot (QD) light-chip micro-spectrometer is proposed in which QDs emit different wavelengths of light that are combined with a spectral reconstruction (SR) algorithm. The QD array itself can play the roles of both the light source and the wavelength division structure. The spectra of samples can be obtained by using this simple light source with a detector and algorithm, and the spectral resolution reaches 9.7 nm in the wavelength range from 580 nm to 720 nm. The area of the QD light chip is 4 × 7.5 mm2, which is 20 times smaller than the halogen light sources of commercial spectrometers. It does not need a wavelength division structure and greatly reduces the volume of the spectrometer. Such a micro-spectrometer can be used for material identification: in a demonstration, three kinds of transparent samples, real and fake leaves, and real and fake blood were classified with an accuracy of 100%. These results indicate that the spectrometer based on a QD light chip has broad application prospects.