The imaging capability of conventional lenses is mainly limited by the diffraction of light,and the so-called superlens has been developed allowing the recovery of evanescent waves in the focal plane.However,the remar...The imaging capability of conventional lenses is mainly limited by the diffraction of light,and the so-called superlens has been developed allowing the recovery of evanescent waves in the focal plane.However,the remarkable focusing behavi-or of the superlens is greatly confined in the near-field regime due to the exponential decay of evanescent waves.To tackle this issue,we design a waveguide metasurface-based superlens with an extraordinary quasi-far-field focusing capability beyond the diffraction limit in the present work.Specifically,we analyze the underlying physical mechanism and provide experimental verification of the proposed superlens.The metasurface superlens is formed by an array of gradient nanoslits perforated in a gold slab,and supports transverse-electric(TE)waveguide modes under linearly polar-ized illumination along the long axis of the slits.Numerical results illustrate that exciting such TE waveguide modes can modulate not only optical phase but also evanescent waves.Consequently,some high-spatial-frequency waves can con-tribute to the focusing of the superlens,leading to the quasi-far-field super-resolution focusing of light.Under 405 nm illu-mination and oil immersion,the fabricated superlens shows a focus spot of 98 nm(i.e.λ/4.13)at a focal distance of 1.49μm(i.e.3.68λ)using an oil immersion objective,breaking the diffraction limit ofλ/2.38 in the quasi-far field regime.The developed metasurface optical superlens with such extraordinary capabilities promises exciting avenues to nanolitho-graphy and ultra-small optoelectronic devices.展开更多
Dear Editor:The measurement and assessment of fluid viscosity,which make it possible to determine fluid flow properties,are critical in the oil,food,cosmetic,pharmaceutical,and chemical industries1–4.To date,however,...Dear Editor:The measurement and assessment of fluid viscosity,which make it possible to determine fluid flow properties,are critical in the oil,food,cosmetic,pharmaceutical,and chemical industries1–4.To date,however,the success in developing rapid,low-cost,miniaturized viscometers covering a wide measurement range has been extremely limited.Herein,a novel design of a viscometer based on the integration of a chip-scale GaN optical device with a bendable strip is reported.展开更多
The ongoing outbreak of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)pandemic has posed significant challenges in early viral diagnosis.Hence,it is urgently desirable to develop a rapid,inexpensive,and s...The ongoing outbreak of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)pandemic has posed significant challenges in early viral diagnosis.Hence,it is urgently desirable to develop a rapid,inexpensive,and sensitive method to aid point-of-care SARS-CoV-2 detection.In this work,we report a highly sequence-specific biosensor based on nanocomposites with aggregationinduced emission luminogens(AIEgen)-labeled oligonucleotide probes on graphene oxide nanosheets(AIEgen@GO)for one step-detection of SARS-CoV-2-specific nucleic acid sequences(Orf1ab or N genes).A dual“turn-on”mechanism based on AIEgen@GO was established for viral nucleic acids detection.Here,the first-stage fluorescence recovery was due to dissociation of the AIEgen from GO surface in the presence of target viral nucleic acid,and the second-stage enhancement of AIEbased fluorescent signal was due to the formation of a nucleic acid duplex to restrict the intramolecular rotation of the AIEgen.Furthermore,the feasibility of our platform for diagnostic application was demonstrated by detecting SARS-CoV-2 virus plasmids containing both Orf1ab and N genes with rapid detection around 1 h and good sensitivity at pM level without amplification.Our platform shows great promise in assisting the initial rapid detection of the SARS-CoV-2 nucleic acid sequence before utilizing quantitative reverse transcription-polymerase chain reaction for second confirmation.展开更多
In this Letter,we developed a robust method for integrating nanodiamonds(NDs)to optical fiber.The NDs,containing nitrogen-vacancy(NV)centers,were uniformly mixed with UV adhesive before coating the end surface of a mu...In this Letter,we developed a robust method for integrating nanodiamonds(NDs)to optical fiber.The NDs,containing nitrogen-vacancy(NV)centers,were uniformly mixed with UV adhesive before coating the end surface of a multimode fiber as a hemispherical film.The excitation and collection efficiency of NV fluorescence can be enhanced by increasing the thickness of UV adhesive film and additional aluminum film deposition.The fiber-based quantum sensor was also experimentally demonstrated for all-optical thermometry application.The variation of the refractive index of UV adhesive under different temperatures will also affect the NV collection efficiency by changing the light confinement.The demonstrated facile integration approach paves the way for developing fiber-based quantum thermometry and magnetometry.展开更多
Cell behaviors and functions show distinct contrast in different mechanical microenvironment.Numerous materials with varied rigidity have been developed to mimic the interactions between cells and their surroundings.H...Cell behaviors and functions show distinct contrast in different mechanical microenvironment.Numerous materials with varied rigidity have been developed to mimic the interactions between cells and their surroundings.However,the conventional static materials cannot fully capture the dynamic alterations at the bio-interface,especially for the molecular motion and the local mechanical changes in nanoscale.As an alternative,flexible materials have great potential to sense and adapt to mechanical changes in such complex microenvironment.The flexible materials could promote the cellular mechanosensing by dynamically adjusting their local mechanics,topography and ligand presentation to adapt to intracellular force generation.This process enables the cells to exhibit comparable or even higher level of mechanotransduction and the downstream‘hard’phenotypes compared to the conventional stiff or rigid ones.Here,we highlight the relevant studies regarding the development of such adaptive materials to mediate cell behaviors across the rigidity limitation on soft substrates.The concept of‘soft overcomes the hard’will guide the future development and application of biological materials.展开更多
基金support by the National Natural Science Foundation of China(52075410,51975483,51622509)the Fundamental Research Funds for the Central Universities(31020190504001)+3 种基金the 111 Project(B13044),the Dean Fund(2019GDYJY05)the Collaborative Innov-ation Center Project of Shaanxi Provincial Department of Education(20JY031)the Natural Science Basic Research Plan in Shaanxi Province of China(2018JQ6012)the Hong Kong Polytechnic University through the“Life Science Research”project(1-ZVH9),and the City University of Hong Kong(9610456).
文摘The imaging capability of conventional lenses is mainly limited by the diffraction of light,and the so-called superlens has been developed allowing the recovery of evanescent waves in the focal plane.However,the remarkable focusing behavi-or of the superlens is greatly confined in the near-field regime due to the exponential decay of evanescent waves.To tackle this issue,we design a waveguide metasurface-based superlens with an extraordinary quasi-far-field focusing capability beyond the diffraction limit in the present work.Specifically,we analyze the underlying physical mechanism and provide experimental verification of the proposed superlens.The metasurface superlens is formed by an array of gradient nanoslits perforated in a gold slab,and supports transverse-electric(TE)waveguide modes under linearly polar-ized illumination along the long axis of the slits.Numerical results illustrate that exciting such TE waveguide modes can modulate not only optical phase but also evanescent waves.Consequently,some high-spatial-frequency waves can con-tribute to the focusing of the superlens,leading to the quasi-far-field super-resolution focusing of light.Under 405 nm illu-mination and oil immersion,the fabricated superlens shows a focus spot of 98 nm(i.e.λ/4.13)at a focal distance of 1.49μm(i.e.3.68λ)using an oil immersion objective,breaking the diffraction limit ofλ/2.38 in the quasi-far field regime.The developed metasurface optical superlens with such extraordinary capabilities promises exciting avenues to nanolitho-graphy and ultra-small optoelectronic devices.
基金financial support from the National Natural Science Foundation of China(Nos.62004088 and 12074170)the Shenzhen Fundamental Research Program(No.JCYJ20220530113201003).
文摘Dear Editor:The measurement and assessment of fluid viscosity,which make it possible to determine fluid flow properties,are critical in the oil,food,cosmetic,pharmaceutical,and chemical industries1–4.To date,however,the success in developing rapid,low-cost,miniaturized viscometers covering a wide measurement range has been extremely limited.Herein,a novel design of a viscometer based on the integration of a chip-scale GaN optical device with a bendable strip is reported.
基金Shenzhen-Hong Kong-Macao Science and Technology Plan Project,Grant/Award Number:SGDX2020110309260000Research Grants Council(RGC)Collaborative Research Fund,Grant/Award Number:C5110-20GF+2 种基金Research Grants Council(RGC)General Research Fund,Grant/Award Numbers:PolyU 15214619,PolyU 15210818Hong Kong Polytechnic University Internal Fund,Grant/Award Numbers:1-ZE1E,1-ZVVQNational Natural Science Foundation of China,Grant/Award Number:31771077。
文摘The ongoing outbreak of Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)pandemic has posed significant challenges in early viral diagnosis.Hence,it is urgently desirable to develop a rapid,inexpensive,and sensitive method to aid point-of-care SARS-CoV-2 detection.In this work,we report a highly sequence-specific biosensor based on nanocomposites with aggregationinduced emission luminogens(AIEgen)-labeled oligonucleotide probes on graphene oxide nanosheets(AIEgen@GO)for one step-detection of SARS-CoV-2-specific nucleic acid sequences(Orf1ab or N genes).A dual“turn-on”mechanism based on AIEgen@GO was established for viral nucleic acids detection.Here,the first-stage fluorescence recovery was due to dissociation of the AIEgen from GO surface in the presence of target viral nucleic acid,and the second-stage enhancement of AIEbased fluorescent signal was due to the formation of a nucleic acid duplex to restrict the intramolecular rotation of the AIEgen.Furthermore,the feasibility of our platform for diagnostic application was demonstrated by detecting SARS-CoV-2 virus plasmids containing both Orf1ab and N genes with rapid detection around 1 h and good sensitivity at pM level without amplification.Our platform shows great promise in assisting the initial rapid detection of the SARS-CoV-2 nucleic acid sequence before utilizing quantitative reverse transcription-polymerase chain reaction for second confirmation.
基金supported by the National Natural Science Foundation of China(No.62075181)financial support from the HKU Start-Up Grant and the Seed Fund(No.202011159019)。
文摘In this Letter,we developed a robust method for integrating nanodiamonds(NDs)to optical fiber.The NDs,containing nitrogen-vacancy(NV)centers,were uniformly mixed with UV adhesive before coating the end surface of a multimode fiber as a hemispherical film.The excitation and collection efficiency of NV fluorescence can be enhanced by increasing the thickness of UV adhesive film and additional aluminum film deposition.The fiber-based quantum sensor was also experimentally demonstrated for all-optical thermometry application.The variation of the refractive index of UV adhesive under different temperatures will also affect the NV collection efficiency by changing the light confinement.The demonstrated facile integration approach paves the way for developing fiber-based quantum thermometry and magnetometry.
基金the financial support from the National Natural Science Foundation of China(Grant No.51973129 and No.32000951)the Sichuan Science and Technology Program(2020YFH0034)+3 种基金the State Key Laboratory of Polymer Materials Engineering,Sichuan University(sklpme2020-2-08)the HKSAR Research Grants Council(RGC)General Research Fund(GRF,no.14306117)Early Career Scheme(ECS,No.27202919)the HKU Start-Up Grant and the Seed Fund(No.202011159019).
文摘Cell behaviors and functions show distinct contrast in different mechanical microenvironment.Numerous materials with varied rigidity have been developed to mimic the interactions between cells and their surroundings.However,the conventional static materials cannot fully capture the dynamic alterations at the bio-interface,especially for the molecular motion and the local mechanical changes in nanoscale.As an alternative,flexible materials have great potential to sense and adapt to mechanical changes in such complex microenvironment.The flexible materials could promote the cellular mechanosensing by dynamically adjusting their local mechanics,topography and ligand presentation to adapt to intracellular force generation.This process enables the cells to exhibit comparable or even higher level of mechanotransduction and the downstream‘hard’phenotypes compared to the conventional stiff or rigid ones.Here,we highlight the relevant studies regarding the development of such adaptive materials to mediate cell behaviors across the rigidity limitation on soft substrates.The concept of‘soft overcomes the hard’will guide the future development and application of biological materials.