Moirémeta-devices facilitate continuous and precise modulation of optical properties through the alteration of the relative alignment,such as twisting,sliding,or rotating of the metasurfaces.This capability rende...Moirémeta-devices facilitate continuous and precise modulation of optical properties through the alteration of the relative alignment,such as twisting,sliding,or rotating of the metasurfaces.This capability renders them particularly suitable for dynamic applications,including zoom optics and adaptive imaging systems.Nevertheless,such designs often sacrifice more complex functionalities,such as polarization manipulation,in favor of simplicity and tunability.Here,we propose and experimentally validate a design strategy for a twisted bilayer metasurface that exhibits both varifocal capabilities and polarization filtering properties.By selecting silicon pillars with polarization-maintaining properties for Layer Ⅰ and polarization-converting properties for Layer Ⅱ,the designed Moirémetasurface can become sensitive to specific polarization states.Experimental results demonstrate that the proposed design can generate on-demand terahertz(THz)focused beams,achieving an average focusing efficiency exceeding 35%under x-linearly polarized(x-LP)illumination.This is accomplished by systematically varying the twisting angles p and q of Layer Ⅰ in relation to Layer Ⅱ in increments of 30°.Additionally,we provide numerical evidence that the focal length of the transmitted vortex beam can be adjusted using the same approach.The Moirémeta-device platform,which is engineered to modulate optical properties via mechanical twisting,obviates the necessity for external power sources or active materials.This generalized design strategy has the potential to significantly expedite the commercialization of multifunctional metasurfaces,which can produce high-precision optics across various practical applications.展开更多
Haptic interactions between human and machines are essential for information acquisition and object manipulation.In virtual reality(VR)system,the haptic sensing device can gather information to construct virtual eleme...Haptic interactions between human and machines are essential for information acquisition and object manipulation.In virtual reality(VR)system,the haptic sensing device can gather information to construct virtual elements,while the haptic feedback part can transfer feedbacks to human with virtual tactile sensation.Therefore,exploring high-performance haptic sensing and feedback interface imparts closedloop haptic interaction to VR system.This review summarizes state-of-the-art VR-related haptic sensing and feedback techniques based on the hardware parts.For the haptic sensor,we focus on mechanism scope(piezoresistive,capacitive,piezoelectric,and triboelectric)and introduce force sensor,gesture translation,and touch identification in the functional view.In terms of the haptic feedbacks,methodologies including mechanical,electrical,and elastic actuators are surveyed.In addition,the interactive application of virtual control,immersive entertainment,and medical rehabilitation is also summarized.The challenges of virtual haptic interactions are given including the accuracy,durability,and technical conflicts of the sensing devices,bottlenecks of various feedbacks,as well as the closed-loop interaction system.Besides,the prospects are outlined in artificial intelligence of things,wise information technology of medicine,and multimedia VR areas.展开更多
基金National Natural Science Foundation of China(U22A2008,12404484)Sichuan Provincial Science and Technology Support Program(25QNJJ2419)+1 种基金National Key Research and Development Program of China(2021YFB2800703)Laoshan Laboratory Science and Technology Innovation Project(LSKJ202200801)。
文摘Moirémeta-devices facilitate continuous and precise modulation of optical properties through the alteration of the relative alignment,such as twisting,sliding,or rotating of the metasurfaces.This capability renders them particularly suitable for dynamic applications,including zoom optics and adaptive imaging systems.Nevertheless,such designs often sacrifice more complex functionalities,such as polarization manipulation,in favor of simplicity and tunability.Here,we propose and experimentally validate a design strategy for a twisted bilayer metasurface that exhibits both varifocal capabilities and polarization filtering properties.By selecting silicon pillars with polarization-maintaining properties for Layer Ⅰ and polarization-converting properties for Layer Ⅱ,the designed Moirémetasurface can become sensitive to specific polarization states.Experimental results demonstrate that the proposed design can generate on-demand terahertz(THz)focused beams,achieving an average focusing efficiency exceeding 35%under x-linearly polarized(x-LP)illumination.This is accomplished by systematically varying the twisting angles p and q of Layer Ⅰ in relation to Layer Ⅱ in increments of 30°.Additionally,we provide numerical evidence that the focal length of the transmitted vortex beam can be adjusted using the same approach.The Moirémeta-device platform,which is engineered to modulate optical properties via mechanical twisting,obviates the necessity for external power sources or active materials.This generalized design strategy has the potential to significantly expedite the commercialization of multifunctional metasurfaces,which can produce high-precision optics across various practical applications.
基金supported by the National Natural Science Foundation of China(61888102)Beijing Natural Science Foundation(L223006)China Postdoctoral Science Foundation(BX20230466 and 2023M740233).
文摘Haptic interactions between human and machines are essential for information acquisition and object manipulation.In virtual reality(VR)system,the haptic sensing device can gather information to construct virtual elements,while the haptic feedback part can transfer feedbacks to human with virtual tactile sensation.Therefore,exploring high-performance haptic sensing and feedback interface imparts closedloop haptic interaction to VR system.This review summarizes state-of-the-art VR-related haptic sensing and feedback techniques based on the hardware parts.For the haptic sensor,we focus on mechanism scope(piezoresistive,capacitive,piezoelectric,and triboelectric)and introduce force sensor,gesture translation,and touch identification in the functional view.In terms of the haptic feedbacks,methodologies including mechanical,electrical,and elastic actuators are surveyed.In addition,the interactive application of virtual control,immersive entertainment,and medical rehabilitation is also summarized.The challenges of virtual haptic interactions are given including the accuracy,durability,and technical conflicts of the sensing devices,bottlenecks of various feedbacks,as well as the closed-loop interaction system.Besides,the prospects are outlined in artificial intelligence of things,wise information technology of medicine,and multimedia VR areas.
