Direct laser writing of volumetric gradient index lenses and waveguides  

作　　者：Christian R.Ocier Corey A.Richards Daniel A.Bacon-Brown Qing Ding Raman Kumar Tanner J.Garcia Jorik van de Groep Jung-Hwan Song Austin J.Cyphersmith Andrew Rhode Andrea N.Perry Alexander J.Littlefield Jinlong Zhu Dajie Xie Haibo Gao Jonah F.Messinger Mark L.Brongersma Kimani C.Toussaint Jr Lynford L.Goddard Paul V.Braun 

机构地区：[1]Department of Materials Science and Engineering,University of Illinois at Urbana-Champaign,Urbana,IL,USA [2]Materials Research Laboratory,University of Illinois at Urbana-Champaign,Urbana,IL,USA [3]Beckman Institute for Advanced Science and Technology,University of Illinois at Urbana-Champaign,Urbana,IL,USA [4]Department of Electrical and Computer Engineering,University of Illinois at Urbana-Champaign,Urbana,IL,USA [5]Department of Materials Science and Engineering,Stanford University,Stanford,CA,USA [6]Carl R.Woese Institute for Genomic Biology,University of Illinois at Urbana-Champaign,Urbana,IL,USA [7]Department of Mechanical Science and Engineering,University of Illinois at Urbana-Champaign,Urbana,IL,USA

出　　处：《Light(Science & Applications)》2020年第1期89-102,共14页光（科学与应用)（英文版）

基　　金：funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences under Award Number DE-SC0019140(Brongersma and Braun group focal characterization collaboration);the University of Illinois at Urbana-Champaign College of Engineering Strategic Research Initiative(proof-of-concept studies);the National Science Foundation(ECCS-1935289)(Goddard group,and Braun group laser patterning).

摘　　要：Direct laser writing(DLW)has been shown to render 3D polymeric optical components,including lenses,beam expanders,and mirrors,with submicrometer precision.However,these printed structures are limited to the refractive index and dispersive properties of the photopolymer.Here,we present the subsurface controllable refractive index via beam exposure(SCRIBE)method,a lithographic approach that enables the tuning of the refractive index over a range of greater than 0.3 by performing DLW inside photoresist-filled nanoporous silicon and silica scaffolds.Adjusting the laser exposure during printing enables 3D submicron control of the polymer infilling and thus the refractive index and chromatic dispersion.Combining SCRIBE’s unprecedented index range and 3D writing accuracy has realized the world’s smallest(15μm diameter)spherical Luneburg lens operating at visible wavelengths.SCRIBE’s ability to tune the chromatic dispersion alongside the refractive index was leveraged to render achromatic doublets in a single printing step,eliminating the need for multiple photoresins and writing sequences.SCRIBE also has the potential to form multicomponent optics by cascading optical elements within a scaffold.As a demonstration,stacked focusing structures that generate photonic nanojets were fabricated inside porous silicon.Finally,an all-pass ring resonator was coupled to a subsurface 3D waveguide.The measured quality factor of 4600 at 1550 nm suggests the possibility of compact photonic systems with optical interconnects that traverse multiple planes.SCRIBE is uniquely suited for constructing such photonic integrated circuits due to its ability to integrate multiple optical components,including lenses and waveguides,without additional printed supports.

关 键 词：INDEX refractive RENDER 

分 类 号：TN24[电子电信—物理电子学]