Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are requi...Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.展开更多
基金H.L.acknowledges the Technology Innovation program(20016234)funded by the Ministry of Trade and Industry&Energy(MOTIE)and the National Research Foundation(NRF)grants(NRF-2019K1A4A7A02113032,NRF-2022M3H4A1A02046445,NRF-2018M3D1A1058997)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentJ.R.acknowledges the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCO,an industry-university strategic grant funded by Samsung Display,and the NRF grants(NRF-2022M3C1A3081312,NRF-2022M3H4A1A02074314,NRF-2019R1A5A8080290,CAMM-2019M3A6B3030637)funded by the MSIT of the Korean government+1 种基金C.W.Q.acknowledges the support by AME Individual Research Grant(IRG)funded by A*STAR,Singapore(Grant No.A2083c0060).J.K.acknowledges the POSTECH Alchemist fellowship.
文摘Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.
