Highly Efficient Broadband Achromatic Microlens Design Based on Low-Dispersion Materials

Metalenses with achromatic performance offer a new opportunity for high-quality imaging with an ultracompact configuration;however,they suffer from complex fabrication processes and low focusing efficiency.In this study,we propose an efficient design method for achromatic microlenses on a wavelength scale using materials with low dispersion,an adequately designed convex surface,and a thickness profile distribution.By taking into account the absolute chromatic aberration,relative focal length shift(FLS),and numerical aperture(NA),microlens with a certain focal length can be realized through our realized map of geometric features.Accordingly,the designed achromatic microlenses with low-dispersion fused silica were fabricated using a focused ion beam,and precise surface profiles were obtained.The fabricated microlenses exhibited a high average focusing efficiency of 65%at visible wavelengths of 410-680 nm and excellent achromatic capability via white light imaging.Moreover,the design exhibited the advantages of being polarization-insensitive and near-diffraction-limited.These results demonstrate the effectiveness of our proposed achromatic microlens design approach,which expands the prospects of miniaturized optics such as virtual and augmented reality,ultracompact microscopes,and biological endoscopy.

Atomically dispersed materials:Ideal catalysts in atomic era

Catalysts can accelerate the chemical reaction rate and effectively promote the molecules transformation,which is of great significance in the research of chemical industry and material science.The extreme utilization of reactive sites has led to the emergence and development of atomically dispersed materials(ADMs).The highly active coordination unsaturated metal sites and fully utilized metal atoms make ADMs show great potential in catalytic reactions.The adjustment of coordination environment and electronic structure provides more possibilities for constructing reactive centers with different properties.This review summarized the application and research progress of ADMs in different fields.The design strategy and structure–activity relationship of ADMs for specific reactions were summarized and analyzed.Moreover,we also provided advices for the challenges and opportunities faced by ADMs in catalytic reactions.

The Chang 7 member of the upper Triassic in the southwest Ordos Basin:Carbon isotope studay of dispersed organic matter and its paleoclimate significance

The carbon isotope δ 13C value of dispersed organic matter in the Upper Triassic sediments in the Ordos basin is （-24.5 to -26.6） ×10^-3 with the carbon being derived from C3-1ike pleustons. The paleoclimate of the Late Triassic, especially during the deposition of the Chang 7 member, was characterized by a hot and humid climate. It underwent four small climate cycles from humid and warm to humid and hot.