Chip-integrated metasurface full-Stokes polarimetric imaging sensor

Abstract Polarimetric imaging has a wide range of applications for uncovering features invisible to human eyes and conventional imaging sensors. Chip-integrated, fast, cost-effective, and accurate full-Stokes polarimetric imaging sensors are highly desirable in many applications, which, however, remain elusive due to fundamental material limitations. Here we present a chip-integrated Metasurface-based Full-Stokes Polarimetric Imaging sensor (MetaPolarIm) realized by integrating an ultrathin (~600 nm) metasurface polarization filter array (MPFA) onto a visible imaging sensor with CMOS compatible fabrication processes. The MPFA is featured with broadband dielectric-metal hybrid chiral metasurfaces and double-layer nanograting polarizers. This chip-integrated polarimetric imaging sensor enables single-shot full-Stokes imaging (speed limited by the CMOS imager) with the most compact form factor, records high measurement accuracy, dual-color operation (green and red) and a field of view up to 40 degrees. MetaPolarIm holds great promise to enable transformative applications in autonomous vision, industry inspection, space exploration, medical imaging and diagnosis

Surface Coating with Hyaluronic Acid-Gelatin-Crosslinked Hydrogel on Gelatin-Conjugated Poly(dimethylsiloxane) for Implantable Medical Device-Induced Fibrosis

Polydimethylsiloxane (PDMS) is a biocompatible polymer that has been applied in many fields. However, the surface hydrophobicity of PDMS can limit successful implementation, and this must be reduced by surface modification to improve biocompatibility. In this study, we modified the PDMS surface with a hydrogel and investigated the effect of this on hydrophilicity, bacterial adhesion, cell viability, immune response, and biocompatibility of PDMS. Hydrogels were created from hyaluronic acid and gelatin using a Schiff-base reaction. The PDMS surface and hydrogel were characterized using nuclear magnetic resonance, X-ray photoelectron spectroscopy, attenuated total reflection Fourier-transform infrared spectroscopy, and scanning electron microscopy. The hydrophilicity of the surface was confirmed via a decrease in the water contact angle. Bacterial anti-adhesion was demonstrated for Pseudomonas aeruginosa, Ralstonia pickettii, and Staphylococcus epidermidis, and viability and improved distribution of human-derived adipose stem cells were also confirmed. Decreased capsular tissue responses were observed in vivo with looser collagen distribution and reduced cytokine expression on the hydrogel-coated surface. Hydrogel coating on treated PDMS is a promising method to improve the surface hydrophilicity and biocompatibility for surface modification of biomedical applications

Unidirectional Doubly Enhanced MoS₂ Emission via Photonic Fano Resonances

Atomically thin transition metal dichalcogenides like MoS₂ monolayers exhibit unique luminescent properties. However, weak quantum yield and low light absorption hinder their practical applications in two-dimensional light emitting devices. Here, we report 1300 times enhancement in photoluminescence emission from a MoS₂ monolayer via simultaneous Fano resonances in a dielectric photonic crystal. The spatially extended double Fano resonance scheme allows resonant enhancement of both the MoS₂ absorption and emission. We also achieve unidirectional emission within a narrow divergence angle of 5° by engineering the Fano resonance angular dispersion. Our approach provides a new platform for efficient light sources with high directionality based on emerging two-dimensional materials

Dynamic Photochemical and Optoelectronic Control of Photonic Fano Resonances via Monolayer MoS₂ Trions

Active tunability of photonic resonances is of great interest for various applications such as optical switching and modulation based on optoelectronic materials. Manipulation of charged excitons in atomically thin transition metal dichalcogenides (TMDCs) like monolayer MoS₂ offers an unexplored route for diverse functionalities in optoelectronic nanodevices. Here, we experimentally demonstrate the dynamic photochemical and optoelectronic control of the photonic crystal Fano resonances by optical and electrical tuning of monolayer MoS₂ refractive index via trions without any chemical treatment. The strong spatial and spectral overlap between the photonic Fano mode and the active MoS₂ monolayer enables efficient modulation of the Fano resonance. Our approach offers new directions for potential applications in the development of optical modulators based on emerging 2D direct band gap semiconductors