Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical pro...Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical properties or functionalities.We demonstrate that such metasurfaces can also be applied for single-lens three-dimensional(3-D)imaging based on a specifically engineered point-spread function(PSF).Using Huygens’metasurfaces with high transmission,we design and realize a phase mask that implements a rotating PSF for 3-D imaging.We experimentally characterize the properties of the realized double-helix PSF,finding that it can uniquely encode object distances within a wide range.Furthermore,we experimentally demonstrate wide-field depth retrieval within a 3-D scene,showing the suitability of metasurfaces to realize optics for 3-D imaging,using just a single camera and lens system.展开更多
日间辐射冷却技术借助材料对太阳光高反射和对中红外大气窗口高发射的光谱特点,提供了一种零耗能的可持续制冷方案.然而,目前辐射冷却器因为实现对太阳光的高反射通常呈现出白色/银色,限制了其实际应用.开发彩色辐射冷却器则至关重要,...日间辐射冷却技术借助材料对太阳光高反射和对中红外大气窗口高发射的光谱特点,提供了一种零耗能的可持续制冷方案.然而,目前辐射冷却器因为实现对太阳光的高反射通常呈现出白色/银色,限制了其实际应用.开发彩色辐射冷却器则至关重要,但由于显示颜色往往导致对太阳光可见光波段的吸收,增加了体系的热负荷,所以实现彩色辐射制冷亚环境冷却一直是个挑战.本文提出了基于高量子发光效率的光致发光彩色辐射冷却器(PCRC),它可以实现全色谱亚环境日间辐射冷却.此外,作者还报道了一种可大规模生产的静电纺丝/喷墨打印方法制备PCRC.PCRC上层的光致发光着色剂实现显色的同时,将因为显色吸收的太阳光在可见光波段转化为发射光,极大地减少了太阳光对体系的加热效应;底层的醋酸纤维素纳米纤维膜能反射其余波段的太阳光并向宇宙辐射热量.这种基于光致发光的彩色辐射制冷器在太阳光直射(辐射峰值>740 W m^(-2))下,其温度比环境温度低2.2~5.4℃,实现了亚环境日间辐射冷却.该设计策略和可放大的图案化制备技术为辐射冷却的多场景应用开辟了一条新道路,并为可持续能源发展提供了一种创新途径.展开更多
基金We thank Waltraud Gräf,Daniel Voigt,Michael Banasch,and Thomas Käsebier for help with the fabrication.Financial support by the German Research Foundation within the Emmy-Noether program and the SPP“Tailored Disorder”(STA 1426/1-1,STA 1426/2-1,PE 1524/10-2)is gratefully acknowledged.Part of this research was funded by the German Federal Ministry of Education and Research(BMBF)under the project identifiers 13N14147 and 03ZZ0434.
文摘Ultrathin metasurfaces have shown the capability to influence all aspects of light propagation.This has made them promising options for replacing conventional bulky imaging optics while adding advantageous optical properties or functionalities.We demonstrate that such metasurfaces can also be applied for single-lens three-dimensional(3-D)imaging based on a specifically engineered point-spread function(PSF).Using Huygens’metasurfaces with high transmission,we design and realize a phase mask that implements a rotating PSF for 3-D imaging.We experimentally characterize the properties of the realized double-helix PSF,finding that it can uniquely encode object distances within a wide range.Furthermore,we experimentally demonstrate wide-field depth retrieval within a 3-D scene,showing the suitability of metasurfaces to realize optics for 3-D imaging,using just a single camera and lens system.
基金jointly supported by the National Key Research and Development Program of China(2021YFA1400700,2020YFA0406104,and 2017YFA0205700)the National Natural Science Foundation of China(52002168,12022403,11874211,61735008,62134009,and 62121005)+4 种基金Science Foundation of Jiangsu(BK20190311)Key Science and Technology Innovation Programme of Shandong Province(2019JZZY020704)Excellent Research Programme of Nanjing University(ZYJH005)the Fundamental Research Funds for the Central Universities(021314380214,021314380190,021314380140,and 021314380150)support from the XPLORER PRIZE。
文摘日间辐射冷却技术借助材料对太阳光高反射和对中红外大气窗口高发射的光谱特点,提供了一种零耗能的可持续制冷方案.然而,目前辐射冷却器因为实现对太阳光的高反射通常呈现出白色/银色,限制了其实际应用.开发彩色辐射冷却器则至关重要,但由于显示颜色往往导致对太阳光可见光波段的吸收,增加了体系的热负荷,所以实现彩色辐射制冷亚环境冷却一直是个挑战.本文提出了基于高量子发光效率的光致发光彩色辐射冷却器(PCRC),它可以实现全色谱亚环境日间辐射冷却.此外,作者还报道了一种可大规模生产的静电纺丝/喷墨打印方法制备PCRC.PCRC上层的光致发光着色剂实现显色的同时,将因为显色吸收的太阳光在可见光波段转化为发射光,极大地减少了太阳光对体系的加热效应;底层的醋酸纤维素纳米纤维膜能反射其余波段的太阳光并向宇宙辐射热量.这种基于光致发光的彩色辐射制冷器在太阳光直射(辐射峰值>740 W m^(-2))下,其温度比环境温度低2.2~5.4℃,实现了亚环境日间辐射冷却.该设计策略和可放大的图案化制备技术为辐射冷却的多场景应用开辟了一条新道路,并为可持续能源发展提供了一种创新途径.
