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| 1 | Direct laser writing of volumetric gradient index lenses and waveguides显示文摘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. | 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 | 2020 | Light(Science & Applications)2020，9，1： | 6 |
| 2 | Overexpression of SHORT VEGETATIVE PHASE-LIKE (SVL) in Populus delays onset and reduces abundance of flowering in field-grown trees显示文摘The spread of transgenes and exotic germplasm from planted crops into wild or feral species is a difficult problem for public and regulatory acceptance of genetically engineered plants,particularly for wind-pollinated trees such as poplar.We report that overexpression of a poplar homolog of the floral repressor SHORT VEGETATIVE PHASE-LIKE(SVL),a homolog of the Arabidopsis MADS-box repressor SHORT VEGETATIVE PHASE(SVP),delayed the onset of flowering several years in three genotypes of field-grown transgenic poplars.Higher expression of SVL correlated with a delay in flowering onset and lower floral abundance,and did not cause morphologically obvious or statistically significant effects on leaf characteristics,tree form,or stem volume.Overexpression effects on reproductive and vegetative phenology in spring was modest and genotype-specific.Our results suggest that use of SVL and related floral repressors can be useful tools to enable a high level of containment for vegetatively propagated short-rotation woody energy or pulp crops. | Greg S.Goralogia Glenn T.Howe Amy M.Brunner Emily Helliwell Michael F.Nagle Cathleen Ma Haiwei Lu Amanda L.Goddard Anna C.Magnuson Amy L.Klocko Steven H.Strauss | 2021 | Horticulture Research2021，8，1： | 1 |
| 3 | British Dietetic Association evidence‐based guidelines for the dietary management of irritable bowel syndrome in adults显示文摘 | Y. A.McKenzie A.Alder W.Anderson A.Wills L.Goddard P.Gulia E.Jankovich P.Mutch L. B.Reeves A.Singer M. C. E.Lomer | 2012 | Journal of Human Nutrition and Dietetics2012，，3： | 1 |
| 4 | Efficient and wideband acousto-optic modulation on thin-film lithium niobate for microwave-to-photonic conversion显示文摘Microwave photonics,a field that crosscuts microwave/millimeter-wave engineering with optoelectronics,has sparked great interest from research and commercial sectors. This multidisciplinary fusion can achieve ultrawide bandwidth and ultrafast speed that were considered impossible in conventional chip-scale microwave/millimeterwave systems. Conventional microwave-to-photonic converters,based on resonant acousto-optic modulation,produce highly efficient modulation but sacrifice bandwidth and limit their applicability for most real-world microwave signal-processing applications. In this paper,we build highly efficient and wideband microwaveto-photonic modulators using the acousto-optic effect on suspended lithium niobate thin films. A wideband microwave signal is first piezoelectrically transduced using interdigitated electrodes into Lamb acoustic waves,which directly propagates across an optical waveguide and causes refractive index pertp urbation through the photoelastic effect. This approach is power-efficient,with phase shifts up to 0.0166 rad∕m W over a 45μm modulation length and with a bandwidth up to 140 MHz at a center frequency of 1.9 GHz. Compared to the state-ofthe-art,a 9×more efficient modulation has been achieved by optimizing the acoustic and optical modes and their interactions. | AHMED E.HASSANIEN STEFFEN LINK YANSONG YANG EDMOND CHOW LYNFORD L.GODDARD SONGBIN GONG | 2021 | Photonics Research2021，9，7： | 1 |
| 5 | Realization of palladium-based optomechanical cantilever hydrogen sensor显示文摘Hydrogen has attracted attention as an alternative fuel source and as an energy storage medium.However,the flammability of hydrogen at low concentrations makes it a safety concern.Thus,gas concentration measurements are a vital safety issue.Here we present the experimental realization of a palladium thin film cantilever optomechanical hydrogen gas sensor.We measured the instantaneous shape of the cantilever to nanometer-level accuracy using diffraction phase microscopy.Thus,we were able to quantify changes in the curvature of the cantilever as a function of hydrogen concentration and observed that the sensor’s minimum detection limit was well below the 250 p.p.m.limit of our test equipment.Using the change in curvature versus the hydrogen curve for calibration,we accurately determined the hydrogen concentrations for a random sequence of exposures.In addition,we calculated the change in film stress as a function of hydrogen concentration and observed a greater sensitivity at lower concentrations. | Steven J.McKeown Xiaozhen Wang Xin Yu Lynford L.Goddard | 2017 | Microsystems & Nanoengineering2017，3，1： | 0 |
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