Graphene quantum dots(GQDs)refer to graphene fragments with a lateral dimension typically less than 100 nm,which possess unique electrical and optical properties due to the quantum confinement effect.In this study,we ...Graphene quantum dots(GQDs)refer to graphene fragments with a lateral dimension typically less than 100 nm,which possess unique electrical and optical properties due to the quantum confinement effect.In this study,we demonstrate that chemically derived graphene quantum dots show great potential for making highly stretchable and cost-effective strain sensors via an electron tunneling mechanism.Stretch-able strain sensors are critical devices for the field of flexible or wearable electronics which are expected to maintain function up to high strain values(>30%).However,strain sensors based on conventional materials(i.e.metal or semiconductors)or metal nanoparticles(e.g.gold or silver nanoparticles)only work within a small range of strain(i.e.the former have a working range<1%and the latter<3%).In this study,by simply dropcasting solution-processed GQDs between the interdigitated electrodes on polydimethylsiloxane,we obtained devices that can function in the range from 0.06%to over 50%ten-sile strain with both the sensitivity and working range conveniently adjustable by the concentration of GQDs applied.This study provides a new concept for practical applications of GQDs,revealing the poten-tial of this material for smart applications such as artificial skin,human-machine interfaces,and health monitoring.展开更多
Integrated photonics is a leading platform for quantum technologies including nonclassical state generation1–4,demonstration of quantum computational complexity5 and secure quantum communications6.As photonic circuit...Integrated photonics is a leading platform for quantum technologies including nonclassical state generation1–4,demonstration of quantum computational complexity5 and secure quantum communications6.As photonic circuits grow in complexity,full quantum tomography becomes impractical,and therefore an efficient method for their characterization7,8 is essential.Here we propose and demonstrate a fast,reliable method for reconstructing the two-photon state produced by an arbitrary quadratically nonlinear optical circuit.By establishing a rigorous correspondence between the generated quantum state and classical sum-frequency generation measurements from laser light,we overcome the limitations of previous approaches for lossy multimode devices9,10.We applied this protocol to a multi-channel nonlinear waveguide network and measured a 99.28±0.31%fidelity between classical and quantum characterization.This technique enables fast and precise evaluation of nonlinear quantum photonic networks,a crucial step towards complex,largescale,device production.展开更多
基金support of a Griffith Publication Assis-tance Scholarship(PAS).Q.L.wishes to thank the support from Australian Research Council(Nos.DP160104089,IH 180100002,and DP 200101105).D.C.is grateful for the support of a Griffith Univer-sity New Researcher Grant.The authors are grateful for the support of centre of Microscopy and Microanalysis(CMM)at the University of Queensland for acquiring SEM and TEM images.The authors also thank the Queensland Node of Australian National Fabrication Fa-cility(ANFF)for their assistance in fabrication of photomasks.
文摘Graphene quantum dots(GQDs)refer to graphene fragments with a lateral dimension typically less than 100 nm,which possess unique electrical and optical properties due to the quantum confinement effect.In this study,we demonstrate that chemically derived graphene quantum dots show great potential for making highly stretchable and cost-effective strain sensors via an electron tunneling mechanism.Stretch-able strain sensors are critical devices for the field of flexible or wearable electronics which are expected to maintain function up to high strain values(>30%).However,strain sensors based on conventional materials(i.e.metal or semiconductors)or metal nanoparticles(e.g.gold or silver nanoparticles)only work within a small range of strain(i.e.the former have a working range<1%and the latter<3%).In this study,by simply dropcasting solution-processed GQDs between the interdigitated electrodes on polydimethylsiloxane,we obtained devices that can function in the range from 0.06%to over 50%ten-sile strain with both the sensitivity and working range conveniently adjustable by the concentration of GQDs applied.This study provides a new concept for practical applications of GQDs,revealing the poten-tial of this material for smart applications such as artificial skin,human-machine interfaces,and health monitoring.
基金supported by the Australian Research Council(ARC)under the Grants DP140100808 and DP160100619the Centre of Excellence for Ultrahigh bandwidth Devices for Optical Systems(CUDOS)+3 种基金Centre of Excellence for Quantum Computation and Communication Technology(CE170100012)the Griffith University Research Infrastructure Programsupported by the Australian Government Research Training Program Scholarshipsupport from the Russian Ministry of Education and Science project 3.1365.2017/4.6。
文摘Integrated photonics is a leading platform for quantum technologies including nonclassical state generation1–4,demonstration of quantum computational complexity5 and secure quantum communications6.As photonic circuits grow in complexity,full quantum tomography becomes impractical,and therefore an efficient method for their characterization7,8 is essential.Here we propose and demonstrate a fast,reliable method for reconstructing the two-photon state produced by an arbitrary quadratically nonlinear optical circuit.By establishing a rigorous correspondence between the generated quantum state and classical sum-frequency generation measurements from laser light,we overcome the limitations of previous approaches for lossy multimode devices9,10.We applied this protocol to a multi-channel nonlinear waveguide network and measured a 99.28±0.31%fidelity between classical and quantum characterization.This technique enables fast and precise evaluation of nonlinear quantum photonic networks,a crucial step towards complex,largescale,device production.
