Optical tweezers(OTs)and optical spanners(OSs)are powerful tools of optical manipulation,which are responsible for particle trapping and rotation,respectively.Conventionally,the OT and OS are built using bulky three-d...Optical tweezers(OTs)and optical spanners(OSs)are powerful tools of optical manipulation,which are responsible for particle trapping and rotation,respectively.Conventionally,the OT and OS are built using bulky three-dimensional devices,such as microscope objectives and spatial light modulators.Recently,metasurfaces are proposed for setting up them on a microscale platform,which greatly miniaturizes the systems.However,the realization of both OT and OS with one identical metasurface is posing a challenge.Here,we offer a metasurface-based solution to integrate the OT and OS.Using the prevailing approach based on geometric and dynamic phases,we show that it is possible to construct an output field,which promises a high-numerical-aperture focal spot,accompanied with a coaxial vortex.Optical trapping and rotation are numerically demonstrated by estimating the mechanical effects on a particle probe.Moreover,we demonstrate an on-demand control of the OT-to-OS distance and the topological charge possessed by the OS.By revealing the OT–OS metasurfaces,our results may empower advanced applications in on-chip particle manipulation.展开更多
The chromatic aberration of metasurfaces limits their application. How to cancel or utilize the large chromatic dispersion of metasurfaces becomes an important issue. Here, we design Si-based metasurfaces to realize f...The chromatic aberration of metasurfaces limits their application. How to cancel or utilize the large chromatic dispersion of metasurfaces becomes an important issue. Here, we design Si-based metasurfaces to realize flexible chromatic dispersion manipulation in mid-infrared region. We demonstrate the broadband achromatic metalens and achromatic gradient metasurface to cancel the chromatic aberration over a continuous bandwidth(8–12 μm). In contrast, the metalens and gradient metasurface with enhanced chromatic dispersion have also been realized, where the focal length and deflection angle with different wavelengths vary more significantly than the conventional devices designed with geometric phase. These demonstrations indicate promising potential applications.展开更多
基金National Natural Science Foundation of China(11621091,11674166,11674167,11674168,11774162,11774164,11804119,11822406,11834007,91850204)Key Technologies Research and Development Program(2016YFA0202103,2017YFA0303700,2017YFA0303702).
文摘Optical tweezers(OTs)and optical spanners(OSs)are powerful tools of optical manipulation,which are responsible for particle trapping and rotation,respectively.Conventionally,the OT and OS are built using bulky three-dimensional devices,such as microscope objectives and spatial light modulators.Recently,metasurfaces are proposed for setting up them on a microscale platform,which greatly miniaturizes the systems.However,the realization of both OT and OS with one identical metasurface is posing a challenge.Here,we offer a metasurface-based solution to integrate the OT and OS.Using the prevailing approach based on geometric and dynamic phases,we show that it is possible to construct an output field,which promises a high-numerical-aperture focal spot,accompanied with a coaxial vortex.Optical trapping and rotation are numerically demonstrated by estimating the mechanical effects on a particle probe.Moreover,we demonstrate an on-demand control of the OT-to-OS distance and the topological charge possessed by the OS.By revealing the OT–OS metasurfaces,our results may empower advanced applications in on-chip particle manipulation.
基金supported by the National Key R&D Program of China (Nos. 2017YFA0303700,2017YFA0303702,and 2016YFA0202103)the National Natural Science Foundation of China (Nos. 11822406,11834007,11774162,11674166,11674167,11674168,11621091,11774164,and 91850204)。
文摘The chromatic aberration of metasurfaces limits their application. How to cancel or utilize the large chromatic dispersion of metasurfaces becomes an important issue. Here, we design Si-based metasurfaces to realize flexible chromatic dispersion manipulation in mid-infrared region. We demonstrate the broadband achromatic metalens and achromatic gradient metasurface to cancel the chromatic aberration over a continuous bandwidth(8–12 μm). In contrast, the metalens and gradient metasurface with enhanced chromatic dispersion have also been realized, where the focal length and deflection angle with different wavelengths vary more significantly than the conventional devices designed with geometric phase. These demonstrations indicate promising potential applications.
