Wide field of view chiral imaging with a liquid crystal planar lens enabled by digitalized nanogratings.

To compensate for the inability for polarization imaging by conventional methods, metasurface optics with compactness and multi-function emerge as an approach to provide images with different linear and circular polarizations. Here, we propose a liquid crystal (LC) geometric phase-based chiral imaging lens (CIL) that simultaneously forms images of objects with opposite helicity. The CIL (Diameter 2.3 cm) was optimized by a spatial multiplexing algorithm and realized using the digital holography technique, where the LC domains were regulated by pixelated nanogratings with varied orientation. We investigated the potential of the patterning technique toward high order LC alignment by balancing the periodicity and depth of the nanogratings. The CIL exhibited a wide field of view of ±20°, which is attributed to the self- assembling effects of LC molecules. The compactness, lightness, and ability to produce chiral images of the LC CIL even at large angles have significant potential for practical polarization imaging.

High-throughput and controllable manufacturing of liquid crystal polymer planar microlens array for compact fingerprint imaging.

The microlens array (MLA) with a small geometric footprint and unique performances, is the key enabler to push the development of photonic devices toward miniaturization, multi-function and large-scale integration. However, the realization of 100% fill-factor (FF) MLAs with high controllability and its mass manufacturing without complex steps has always been a difficult issue. Here, we propose an efficient, highly flexible and low-cost manufacturing approach for MLAs with a high FF via snapshot polarization patterning. The digitalized linear polarization pattern was distributed across the photo-alignment layer with both high efficiency and accuracy, enabling large-area liquid crystal MLA with parameter controllability from element to element. The MLA manufacturing process does not involve developing, etching and deposition steps and is suitable for industry up-scaling. We further proposed a novel compact compound-eye imaging system for biometrics with the obtained MLAs. The 100% FF MLA enables high light utilization efficiency and low background crosstalk, yielding compact biometrics indentation with high recognition accuracy. The realization of such planar optics would lead to a plethora of different miniaturized multiaperture imaging systems in the future.