Reconfigurable intelligent surfaces(RISs)are a promising technology for wireless communication applications,but their performance is often optimized using simplified electromagnetic reradiation models.In this study,we...Reconfigurable intelligent surfaces(RISs)are a promising technology for wireless communication applications,but their performance is often optimized using simplified electromagnetic reradiation models.In this study,we explore the impact on the RIS performance of more realistic assumptions,including the(possibly imperfect)quantization of the reflection coefficients,subwavelength inter-element spacing,near-field location,and presence of electromagnetic interference.We find that design constraints can cause an RIS to reradiate power in unwanted directions.Therefore,it is important to optimize an RIS by considering the entire reradiation pattern.Overall,our study indicates that a 2-bit digitally controllable RIS with a nearly constant reflection amplitude and RIS elements with a size and inter-element spacing between(1/8)th and(1/4)th of the signal wavelength may offer a reasonable tradeoff between performance,complexity,and cost.展开更多
We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numer...We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numerical and experimental results pertaining to various prototypes implementing generalized forms of the Snell’s transmission/reflection laws at near-infrared wavelengths.In particular,we demonstrate several examples of beam steering and coupling with surface waves,in fairly good agreement with theory.Our results constitute a first step toward the integration of unprecedented(metasurface-enabled)light-manipulation capabilities in optical-fiber technology.By further enriching the emergent‘lab-on-fiber’framework,this may pave the way for the widespread diffusion of optical metasurfaces in real-world applications to communications,signal processing,imaging and sensing.展开更多
基金supported by the European Commission through the H2020 ARIADNE project(871464)the H2020 RISE-6G project(101017011)+2 种基金the H2020 MetaWireless project(956256)the H2020 PAINLESS project(812991)the Fulbright Foundation under the“Programme National Chercheurs 2021”funding scheme,and the Agence Nationale de la Recherche(ANR)through the PEPR-5G project.
文摘Reconfigurable intelligent surfaces(RISs)are a promising technology for wireless communication applications,but their performance is often optimized using simplified electromagnetic reradiation models.In this study,we explore the impact on the RIS performance of more realistic assumptions,including the(possibly imperfect)quantization of the reflection coefficients,subwavelength inter-element spacing,near-field location,and presence of electromagnetic interference.We find that design constraints can cause an RIS to reradiate power in unwanted directions.Therefore,it is important to optimize an RIS by considering the entire reradiation pattern.Overall,our study indicates that a 2-bit digitally controllable RIS with a nearly constant reflection amplitude and RIS elements with a size and inter-element spacing between(1/8)th and(1/4)th of the signal wavelength may offer a reasonable tradeoff between performance,complexity,and cost.
文摘We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numerical and experimental results pertaining to various prototypes implementing generalized forms of the Snell’s transmission/reflection laws at near-infrared wavelengths.In particular,we demonstrate several examples of beam steering and coupling with surface waves,in fairly good agreement with theory.Our results constitute a first step toward the integration of unprecedented(metasurface-enabled)light-manipulation capabilities in optical-fiber technology.By further enriching the emergent‘lab-on-fiber’framework,this may pave the way for the widespread diffusion of optical metasurfaces in real-world applications to communications,signal processing,imaging and sensing.
