Colloidal quantum dots(CQDs)are of interest for optoelectronic devices because of the possibility of high-throughput solution processing and the wide energy gap tunability from ultraviolet to infrared wavelengths.Peop...Colloidal quantum dots(CQDs)are of interest for optoelectronic devices because of the possibility of high-throughput solution processing and the wide energy gap tunability from ultraviolet to infrared wavelengths.People may question about the upper limit on the CQD wavelength region.To date,although the CQD absorption already reaches terahertz,the practical photodetection wavelength is limited within mid-wave infrared.To figure out challenges on CQD photoresponse in longer wavelength,would reveal the ultimate property on these nanomaterials.What’s more,it motivates interest in bottom-up infrared photodetection with less than 10%cost compared with epitaxial growth semiconductor bulk.In this work,developing a re-growth method and ionic doping modification,we demonstrate photodetection up to 18μm wavelength on HgTe CQD.At liquid nitrogen temperature,the responsivity reaches 0.3 A/W and 0.13 A/W,with specific detectivity 6.6×108 Jones and 2.3×109 Jones for 18μm and 10μm CQD photoconductors,respectively.This work is a step toward answering the general question on the CQD photodetection wavelength limitation.展开更多
Over the last few decades,ultrafast laser processing has become a widely used tool for manufacturing microstructures and nanostructures.The real-time monitoring of laser material processing provides opportunities to i...Over the last few decades,ultrafast laser processing has become a widely used tool for manufacturing microstructures and nanostructures.The real-time monitoring of laser material processing provides opportunities to inspect processes and provide feedback.To date,in-situ and real-time monitoring of laser material processing has rarely been performed.To this end,we propose dual-path snapshot compressive microscopy(DP-SCM)for high-speed,large field-of-view,and high-resolution imaging for in-situ and real-time ultrafast laser processing.In the evaluation of DP-SCM,the field of view,lateral resolution,and imaging speed were measured to be 2 mm,775 nm,and 500 fps,respectively.In ultrafast laser processing,the laser scanning process is observed using a DP-SCM system when translating the sample stage and scanning the focused femtosecond laser.Finally,we monitored the development of a self-organized nanograting structure to validate the potential of our system for unveiling new material mechanisms.The proposed method serves as an add-up(plug-and-play)module for any imaging setup and has vast potential for opening new avenues for high-throughput imaging in laser material processing.展开更多
Refractive index(RI)sensors play an important role in various applications including biomedical analysis and food processing industries.However,developing RI sensors with both high resolution and wide linear range rem...Refractive index(RI)sensors play an important role in various applications including biomedical analysis and food processing industries.However,developing RI sensors with both high resolution and wide linear range remains a great challenge due to the tradeoff between quality(Q)factor and free spectral range(FSR)of resonance mode.Herein,the optical steelyard principle is presented to address this challenge by synergizing resonances from the FabryPerot(FP)cavity and metasurface,integrated in a hybrid configuration form on the end facet of optical fibers.Specifically,the FP resonance acting like the scale beam,offers high resolution while the plasmonic resonance acting like the weight,provides a wide linear range.Featuring asymmetric Fano spectrum due to modal coupling between these two resonances,a high Q value(~3829 in liquid)and a sensing resolution(figure of merit)of 2664 RIU^(-1)are experimentally demonstrated.Meanwhile,a wide RI sensing range(1.3301.430 in the simulation and 1.34031.3757 in the experiment)is realized,corresponding to a spectral shift across several FSRs(four and two FSRs in the simulation and experiment,respectively).The proposed steelyard RI sensing strategy is promising in versatile monitoring applications,e.g.,water salinity/turbidity and biomedical reaction process,and could be extended to other types of sensors calling for both high resolution and wide linear range.展开更多
Extreme ultraviolet(EUV)light is difficult to focus due to strong absorption of most materials.Photon sieves(PS),rather than Fresnel zone plates(FZP),can focus EUV to smaller spot and suppress the higher orders of sec...Extreme ultraviolet(EUV)light is difficult to focus due to strong absorption of most materials.Photon sieves(PS),rather than Fresnel zone plates(FZP),can focus EUV to smaller spot and suppress the higher orders of secondary maxima by several orders of magnitude.The number of pinholes used in PS is far more than that of transparent rings used in FZP,providing a great flexibility to manipulate structured focusing in EUV.In this work we investigate the Fermat-spiral PS to produce focused vortices with different topological charges.Experiment at the wavelength of 46.9 nm is carried out and multi-planar coherent diffractive imaging is used to retrieve the phase map of the focused EUV vortices.These results show the enormous potential of PS for manipulating EUV light.This study not only provides a compact,affordable substitute to focusing vortices where transmissive optics materials are unavailable,but also provides a route of converting various complex light manipulation ranging from visible light to EUV and soft x-ray.展开更多
Pulsed polarized vortex beams,a special form of structured light,are generated by tailoring the light beam spatiotemporally and witness the growing application demands in nonlinear optics such as ultrafast laser proce...Pulsed polarized vortex beams,a special form of structured light,are generated by tailoring the light beam spatiotemporally and witness the growing application demands in nonlinear optics such as ultrafast laser processing and surface plasma excitation.However,existing techniques for generating polarized vortex beams suffer from either low compactness due to the use of bulky components or limited controlment of pulse performance.Here,an all-fiber technique combining plasmonic metafibers with mode conversion method is harnessed to generate high-performance pulsed polarized vortex beams.Plasmonic metafibers are utilized as saturable absorbers to produce Q-switched pulses with micro-second duration,while the offset splicing method is employed to partially convert the fundamental transverse mode(LP_(01))to higher-order mode(LP_(11)).Eventually,a polarized vortex beams laser is achieved at the telecom band with a repetition frequency of 116.0 kHz.The impact of geometrical parameters including period of metafibers and offset of splicing on the spatiotemporal properties of pulsed polarized vortex beams is systematically investigated.Our findings could pave the way for design,control and generation of all-fiber pulsed polarized vortex beams,and also offer insights into the development of other types of structured laser sources.展开更多
基金Westlake Institute for Optoelectronics(No.2024GD003)National Natural Science Foundation of China(No.62105022,No.U22A2081)Beijing National Laboratory for Condensed Matter Physics(No.2023BNLCMPKF012).
文摘Colloidal quantum dots(CQDs)are of interest for optoelectronic devices because of the possibility of high-throughput solution processing and the wide energy gap tunability from ultraviolet to infrared wavelengths.People may question about the upper limit on the CQD wavelength region.To date,although the CQD absorption already reaches terahertz,the practical photodetection wavelength is limited within mid-wave infrared.To figure out challenges on CQD photoresponse in longer wavelength,would reveal the ultimate property on these nanomaterials.What’s more,it motivates interest in bottom-up infrared photodetection with less than 10%cost compared with epitaxial growth semiconductor bulk.In this work,developing a re-growth method and ionic doping modification,we demonstrate photodetection up to 18μm wavelength on HgTe CQD.At liquid nitrogen temperature,the responsivity reaches 0.3 A/W and 0.13 A/W,with specific detectivity 6.6×108 Jones and 2.3×109 Jones for 18μm and 10μm CQD photoconductors,respectively.This work is a step toward answering the general question on the CQD photodetection wavelength limitation.
基金supported by the National Natural Science Foundation of China(62271414)Science Fund for Distinguished Young Scholars of Zhejiang Province(LR23F010001)Research Center for Industries of the Future(RCIF)at Westlake University.and Key Project of the Westlake Institute for Optoelectronics(Grant No.2023GD007).
文摘Over the last few decades,ultrafast laser processing has become a widely used tool for manufacturing microstructures and nanostructures.The real-time monitoring of laser material processing provides opportunities to inspect processes and provide feedback.To date,in-situ and real-time monitoring of laser material processing has rarely been performed.To this end,we propose dual-path snapshot compressive microscopy(DP-SCM)for high-speed,large field-of-view,and high-resolution imaging for in-situ and real-time ultrafast laser processing.In the evaluation of DP-SCM,the field of view,lateral resolution,and imaging speed were measured to be 2 mm,775 nm,and 500 fps,respectively.In ultrafast laser processing,the laser scanning process is observed using a DP-SCM system when translating the sample stage and scanning the focused femtosecond laser.Finally,we monitored the development of a self-organized nanograting structure to validate the potential of our system for unveiling new material mechanisms.The proposed method serves as an add-up(plug-and-play)module for any imaging setup and has vast potential for opening new avenues for high-throughput imaging in laser material processing.
基金support from the National Natural Science Foundation of China(62275221).
文摘Refractive index(RI)sensors play an important role in various applications including biomedical analysis and food processing industries.However,developing RI sensors with both high resolution and wide linear range remains a great challenge due to the tradeoff between quality(Q)factor and free spectral range(FSR)of resonance mode.Herein,the optical steelyard principle is presented to address this challenge by synergizing resonances from the FabryPerot(FP)cavity and metasurface,integrated in a hybrid configuration form on the end facet of optical fibers.Specifically,the FP resonance acting like the scale beam,offers high resolution while the plasmonic resonance acting like the weight,provides a wide linear range.Featuring asymmetric Fano spectrum due to modal coupling between these two resonances,a high Q value(~3829 in liquid)and a sensing resolution(figure of merit)of 2664 RIU^(-1)are experimentally demonstrated.Meanwhile,a wide RI sensing range(1.3301.430 in the simulation and 1.34031.3757 in the experiment)is realized,corresponding to a spectral shift across several FSRs(four and two FSRs in the simulation and experiment,respectively).The proposed steelyard RI sensing strategy is promising in versatile monitoring applications,e.g.,water salinity/turbidity and biomedical reaction process,and could be extended to other types of sensors calling for both high resolution and wide linear range.
基金supported by the National Natural Science Foundation of China(NSFC)(62175245,62005066,61875045,62105345,62305220 and 92050202)Shanghai Sailing Program(21YF1453700 and 23YF1429300)Strategic Priority Research Program of Chinese Academy of Sciences(XDA25020302 and XDA25020104).
文摘Extreme ultraviolet(EUV)light is difficult to focus due to strong absorption of most materials.Photon sieves(PS),rather than Fresnel zone plates(FZP),can focus EUV to smaller spot and suppress the higher orders of secondary maxima by several orders of magnitude.The number of pinholes used in PS is far more than that of transparent rings used in FZP,providing a great flexibility to manipulate structured focusing in EUV.In this work we investigate the Fermat-spiral PS to produce focused vortices with different topological charges.Experiment at the wavelength of 46.9 nm is carried out and multi-planar coherent diffractive imaging is used to retrieve the phase map of the focused EUV vortices.These results show the enormous potential of PS for manipulating EUV light.This study not only provides a compact,affordable substitute to focusing vortices where transmissive optics materials are unavailable,but also provides a route of converting various complex light manipulation ranging from visible light to EUV and soft x-ray.
基金supported by the National Natural Science Foundation of China(Grant No.62071016)the State Key Laboratory of Advanced Optical Communication Systems and Networks,China,and College Students Innovative Entrepreneurial Training Plan Program.
文摘Pulsed polarized vortex beams,a special form of structured light,are generated by tailoring the light beam spatiotemporally and witness the growing application demands in nonlinear optics such as ultrafast laser processing and surface plasma excitation.However,existing techniques for generating polarized vortex beams suffer from either low compactness due to the use of bulky components or limited controlment of pulse performance.Here,an all-fiber technique combining plasmonic metafibers with mode conversion method is harnessed to generate high-performance pulsed polarized vortex beams.Plasmonic metafibers are utilized as saturable absorbers to produce Q-switched pulses with micro-second duration,while the offset splicing method is employed to partially convert the fundamental transverse mode(LP_(01))to higher-order mode(LP_(11)).Eventually,a polarized vortex beams laser is achieved at the telecom band with a repetition frequency of 116.0 kHz.The impact of geometrical parameters including period of metafibers and offset of splicing on the spatiotemporal properties of pulsed polarized vortex beams is systematically investigated.Our findings could pave the way for design,control and generation of all-fiber pulsed polarized vortex beams,and also offer insights into the development of other types of structured laser sources.
