Metasurfaces with compact footprint and large information capacity bring unprecedented possibilities for the miniaturized optoelectronic systems. With the further exploration of intriguing wavefront tailoring possibilities, multiple dimensional multiplexing and dynamic modulation techniques combined with metasurface designs gradually become crucial research trends. Here, we utilize resonance effects and geometric phase of metasurfaces to simultaneously shape the amplitude, phase and polarization of light, and rebuild a vectorial holography with customized patterns and polarizations. By selecting the desired polarization combination continuously, dynamic display of vectorial meta-holography with 4-fold degeneracy is demonstrated. Such a method can precisely modulate the spatial phase and polarization distributions simultaneously at each frame, while the dynamic tunability is easy to implement based on polarization rotation. Such versatile and compact metasurfaces may provide promising solutions to dynamic and near-eye display, compact LiDAR, optical encryption, and date storage.

With the development of micro/nano fabrication technology, metasurface holography has emerged as a revolutionary technology for the manipulation of light with excellent performance. However, for applications of full-Stokes polarization encryption and time sequence holographic display, multiplexing strategies of metasurfaces with large bandwidths and simple operations still need to be developed. As one of the most popular schemes of multiplexing, polarization multiplexed metasurfaces have shown flexible recording abilities for both free-space beam and surface waves. Here, by using a dielectric metasurface equipped with double phase holograms, we have achieved flexible polarization multiplexed transformations from one full-Stokes space to another. The vectorial hologram is optimized by a hybrid genetic algorithm and digitalized with subwavelength modulated units. Based on a quantitative map and remarkable information capacity, time sequence holographic display and complex optical encryption are experimentally demonstrated by changing input/output polarization channels in real time. We believe our method will facilitate applications in smart compact devices of dynamic display, dynamic optical manipulation, optical encryption, anticounterfeiting, etc.

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As an artificial planar composite medium, optical metasurfaces exhibit powerful multidimensional optical modulations at the subwavelength scale. With the aid of intelligent algorithms, versatile wavefront engineering and holographic multiplexing based on optical metasurfaces are being intensively developed. Micronano manufacturing technology provides indispensable support for proof-of-concept and mass production. With the support of these advanced technologies, optical metasurfaces have been developed for a wide range of applications and their compactness, versatility, and compatibility have been fully demonstrated. In this Perspective, we summarize recent advances. In addition, we discuss the challenges and prospects of optical metasurfaces.

Emerging studies show that circRNA catenin beta 1 (circCTNNB1) plays a critical role in cancer. However, the expression and function of circCTNNB1 in cerebral ischemia/reperfusion injury (IRI) have not been reported. The present study discovered that circCTNNB1 and scavenger receptor class B type 1 (SRB1) expression levels were significantly down-regulated in mouse astrocytes (mAS) treated with oxygen glucose deprivation and reperfusion (OGD/R), and similar results were observed in a mouse middle cerebral artery occlusion model. Overexpression of circCTNNB1 alleviated cell apoptosis, oxidative stress and the inflammatory response induced by OGD/R in vitro . Up-regulation of circCTNNB1 increased SRB1 expression levels to protect mAS cells from OGD/R-induced damage. CircCTNNB1 and SRB1 interacted with miR-96-5p, and the overexpression of miR-96-5p efficiently reversed the function of circCTNNB1 in OGD/R-treated mAS cells. CircCTNNB1 protected against cerebral ischemia-reperfusion injury by up-regulating SRB1 in vivo . In conclusion, our findings suggest that circCTNNB1 acts as a competitive endogenous RNA for miR-96-5p to alleviate cerebral IRI, which provides novel evidence that circCTNNB1 and SRB1 may be biomarkers and therapeutic targets for cerebral IRI.

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Metasurfaces are promising platforms for integrated compact optical systems. Traditional metasurface holography design algorithms are limited to information capacity due to finite spatial bandwidth production, which is insufficient for the growing demand for big data storage and encryption. Here, we propose and demonstrate deep learning empowered ultra-dense complex-amplitude holography using step-moving cascaded metasurfaces. Using deep learning artificial intelligence optimization strategy, the barriers of traditional algorithms can be conquered to meet diverse practical requirements. Two metasurfaces are cascaded to form the desired holography. One of them can move to switch the reconstruction images due to diffraction propagation accumulated during the cascaded path. The diffraction pattern from the first metasurface propagates at a different distance and meets with the second metasurface, reconstructing the target holographic reconstructions in the far-field. Such a technique can provide a new solution for multi-dimensional beam shaping, optical encryption, camouflage, integrated on-chip ultra-high-density storage, etc.

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