PhD student Jian Xiong, Postdoctor Xusheng Cai, and Associate professor Kaiyu Cui published paper “Dynamic brain spectrum acquired by a real-time ultraspectral imaging chip with reconfigurable metasurfaces” in Optica, the flagship journal of the Optical Society of America, on April 22, 2022. (https://opg.optica.org/optica/fulltext.cfm?uri=optica-9-5-461&id=471618)

As fingerprints of matter, optical spectrum contains rich information about the interaction between light and matter. Real-time spectral imaging can obtain dynamic spectra of all the image pixels, which introduces a new dimension of information for the intelligent society and has a huge application demand in many fields.

In this study, a reconfigurable metasurface supercell is proposed, which solves the problem that spectral resolution and spatial resolution cannot be reconciled in computational spectroscopy. In experiments, a real-time ultraspectral imaging chip is demonstrated. Benefiting from the capability of multiplexing and reconfiguration of the metasurface supercell, the chip has an overall size of only 0.5 cm² with integrating more than 150,000 micro-spectrometers. The spectral imaging chip operates in the visible band of 450-750 nm, and the resolution of double peaks is as high as 0.8 nm.

Using the real-time ultraspectral imaging chips, the dynamic changes of the characteristic spectrum of hemoglobin and its derivatives in the vivo rat brain were measured with a temporal resolution of up to 30 Hz for the first time. This technology can be further used to derive the activity of neurons in the brain through the mechanism of neurovascular coupling. As a non-invasive detection method, this work shows the great potential of the proposed spectral imaging chip in the field of real-time sensing.

Jian Xiong^†, Xusheng Cai^†, Kaiyu Cui^†*, Yidong Huang, Jiawei Yang, Hongbo Zhu, Wenzheng Li, Bo Hong, Shijie Rao, Zekun Zheng, Sheng Xu, Yuhan He, Fang Liu, Xue Feng, and Wei Zhang, "Dynamic brain spectrum acquired by a real-time ultraspectral imaging chip with reconfigurable metasurfaces," Optica 9, 461-468 (2022)