Near-field scanning optical microscopy is used to investigate the waveguiding properties of optical micro/nanofibres （MNFs） by means of detecting optical power carried by evanescent waves. Taper drawn silica and tel...Near-field scanning optical microscopy is used to investigate the waveguiding properties of optical micro/nanofibres （MNFs） by means of detecting optical power carried by evanescent waves. Taper drawn silica and tellurite MNFs, supported on low-index substrates, are used to guide a 532-nm-wavelength light beam for the test. Modification of the single-mode condition of the MNF in the presence of a substrate is observed. Spatial modulation of the longitudinal field intensity （with a 195-nm period） near the output end of a 760-nm-diameter silica MNF is well resolved. Energy exchange through evanescent coupling between two parallel MNFs is also investigated.展开更多
The multimode evolution, optical losses and wavelength response of non-adiabatic micro/nano-fiber （MNF） tapers are numerically simulated using a three-dimensional finite-difference beam propagation method. For a non...The multimode evolution, optical losses and wavelength response of non-adiabatic micro/nano-fiber （MNF） tapers are numerically simulated using a three-dimensional finite-difference beam propagation method. For a non-adiabatic MNF taper, it is illustrated that optical losses vary with the transition region length and the optical wavelength. We explain how the complicated multimode evolutions result in the complicated optical loss and wavelength response properties, especially when the waist diameters are large enough to allow much higher-order modes. These results may offer valuable references for trapping and guiding cold atoms in atom optics and practical application of micro/nano-devices.展开更多
Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biol...Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biological interfaces.While electronic skin continues to achieve higher sensitivity and faster response,its ultimate performance is fundamentally limited by the nature of low-frequency AC currents.Herein,highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers(MNFs)in thin layers of polydimethylsiloxane(PDMS).Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli,the skin-like optical sensors show ultrahigh sensitivity(1870 k·Pa^-1),low detection limit(7 mPa)and fast response(10μs)for pressure sensing,significantly exceeding the performance metrics of state-of-the-art electronic skins.Electromagnetic interference(EMI)-free detection of high-frequency vibrations,wrist pulse and human voice are realized.Moreover,a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated.These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.展开更多
A generalized formula of hollow Gaussian beams through the first-order misaligned ABCD systems is derived by using the generalized diffraction integral formula. It is shown that the hollow Gaussian beam passing throug...A generalized formula of hollow Gaussian beams through the first-order misaligned ABCD systems is derived by using the generalized diffraction integral formula. It is shown that the hollow Gaussian beam passing through the misaligned system becomes a decentred hollow Gaussian beam. The propagation properties of the output beam are investigated when it propagates through a simple misaligned lens system. These results provide a powerful theoretical tool for applications of optical traps.展开更多
A new organic-inorganic hybrid material doped with BDK that exhibits a large photo-induced change in optical properties is prepared by the sol-gel method.The photosensitivity of the film under ultraviolet irradiation ...A new organic-inorganic hybrid material doped with BDK that exhibits a large photo-induced change in optical properties is prepared by the sol-gel method.The photosensitivity of the film under ultraviolet irradiation is investigated with various exposure times.An increase in refractive index from 1.558 to 1.592 atλ=550 nm is observed together with a 57.3%expansion in physical thickness.The film's optical thickness exhibits an exponential change with the irradiation time.The photo-decomposition of BDK organic groups confirmed by the infrared absorption spectrum contributes to the photosensitive mechanism.A first example of photo-patterning is finally presented by direct light writing.展开更多
Flexible strain sensors play an important role in electronic skins,wearable medical devices,and advanced robots.Herein,a highly sensitive and fast response optical strain sensor with two evanescently coupled optical m...Flexible strain sensors play an important role in electronic skins,wearable medical devices,and advanced robots.Herein,a highly sensitive and fast response optical strain sensor with two evanescently coupled optical micro/nanofibers(MNFs)embedded in a polydimethylsiloxane(PDMS)film is proposed.The strain sensor exhibits a gauge factor as high as 64.5 for strain≤0.5%and a strain resolution of 0.0012%which corresponds to elongation of 120 nm on a 1 cm long device.As a proof-of-concept,highly sensitive fingertip pulse measurement is realized.The properties of fast temporal frequency response up to 30 kHz and a pressure sensitivity of 102 kPa^(−1) enable the sensor for sound detection.Such versatile sensor could be of great use in physiological signal monitoring,voice recognition and micro-displacement detection.展开更多
Long-term optical data storage(ODS)technology is essential to break the bottleneck of high energy consumption for information storage in the current era of big data.Here,ODS with an ultralong lifetime of 2×10^(7)...Long-term optical data storage(ODS)technology is essential to break the bottleneck of high energy consumption for information storage in the current era of big data.Here,ODS with an ultralong lifetime of 2×10^(7)years is attained with single ultrafast laser pulse induced reduction of Eu^(3+)ions and tailoring of optical properties inside the Eu-doped aluminosilicate glasses.We demonstrate that the induced local modifications in the glass can stand against the temperature of up to 970 K and strong ultraviolet light irradiation with the power density of 100 kW/cm^(2).Furthermore,the active ions of Eu^(2+)exhibit strong and broadband emission with the full width at half maximum reaching 190 nm,and the photoluminescence(PL)is flexibly tunable in the whole visible region by regulating the alkaline earth metal ions in the glasses.The developed technology and materials will be of great significance in photonic applications such as long-term ODS.展开更多
Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic ...Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.展开更多
Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measure...Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measurement accuracy. In this paper, first, we review the nonlinear effects of the projector-camera system in the phase-shifting structured light depth measurement method. We show that high order harmonic wave components lead to phase error in the phase-shifting method. Then a practical method based on frequency domain filtering is proposed for nonlinear error reduction. By using this method, the nonlinear calibration of the SL system is not required. Moreover, both the nonlinear effects of the projector and the camera can be effectively reduced. The simulations and experiments have verified our nonlinear correction method.展开更多
In this Letter we outline a dielectric multilayer spectrally selective filter designed for solar energy applications.The optical performance of this 78-layer interference filter constructed by TiOx and SiO_(2) is pres...In this Letter we outline a dielectric multilayer spectrally selective filter designed for solar energy applications.The optical performance of this 78-layer interference filter constructed by TiOx and SiO_(2) is presented.A hybrid system combining photovoltaic cells with a solar-powered Stirling engine using the designed filter is analyzed.The calculated results show the advantages of this spectrally selective method for solar power generation.展开更多
Flexible optical sensors have been an emerging paradigm for applications in robotics,healthcare,and human–machine interfaces due to their high sensitivity,fast response,and anti-electromagnetic interference.Recently,...Flexible optical sensors have been an emerging paradigm for applications in robotics,healthcare,and human–machine interfaces due to their high sensitivity,fast response,and anti-electromagnetic interference.Recently,Marques reports a bioinspired multifunctional flexible optical sensor(BioMFOS),achieving a forces sensitivity of 13.28μN,and a spatial resolution of 0.02 mm.The BioMFOS has a small dimension(around 2 cm)and a light weight(0.8 g),making it suitable for wearable application and clothing integration.As proof-of-concept demonstrations,monitoring of finger position,trunk movements,and respiration rate are realized,implying their prominent applications in remote healthcare,intelligent robots,assistance devices teleoperation,and human-machine interfaces.展开更多
We experimentally demonstrate the C-band wavelength conversion using four-wave mixing in a 17-mm-long silicon-on-insulator waveguide pumped by a dispersed mode-locked femtosecond laser pulse. The idler can be observed...We experimentally demonstrate the C-band wavelength conversion using four-wave mixing in a 17-mm-long silicon-on-insulator waveguide pumped by a dispersed mode-locked femtosecond laser pulse. The idler can be observed with an incident average pump power lower than 4 dBm, and about 35 nm of conversion bandwidth from 1530nm to 1565nm is measured by using a 1550-nm pump wavelength. The pulse-pumped efficiency is demonstrated to be higher, by more than 22 dB, than the cw-pumped efficiency. The conversion efficiency variations with respect to the pump and signal powers are also investigated.展开更多
The past two decades have seen a drastic progress in the development of semiconducting metal-halide perovskites(MHPs)from both the fundamentally scientific and technological points of view.The excellent optoelectronic...The past two decades have seen a drastic progress in the development of semiconducting metal-halide perovskites(MHPs)from both the fundamentally scientific and technological points of view.The excellent optoelectronic properties and device performance make perovskites very attractive to the researchers in materials,physics,chemistry and so on.To fully explore the potential of perovskites in the applications,various techniques have been demonstrated to synthesize perovskites,modify their structures,and create patterns and devices.Among them,photo-processing has been revealed to be a facile and general technique to achieve these aims.In this review,we discuss the mechanisms of photo-processing of perovskites and summarize the recent progress in the photo-processing of perovskites for synthesis,patterning,ion exchange,phase transition,assembly,and ion migration and redistribution.The applications of photo-processed perovskites in photovoltaic devices,lasers,photodetectors,light-emitting diodes(LEDs),and optical data storage and encryption are also discussed.Finally,we provide an outlook on photo-processing of perovskites and propose the promising directions for future researches.This review is of significance to the researches and applications of perovskites and also to uncover new views on the light-matter interactions.展开更多
Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integra...Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integration. Up to now, many different methods have been proposed, among which wide-field, label-free super resolution microscopy is indispensable due to its good applicability to diverse sample types, large field of view（FOV）, and high imaging speed. In recent years,nanostructures have made a crucial contribution to the wide-field, label-free subdiffraction microscopy, with various working mechanisms and configuration designs. This review summarizes the recent applications of the nanostructures in the wide-field, label-free super resolution microscopy, with the emphasis on the designs of hyperlens with hyperbolic dispersion, microsphere with ＂nano-jets＂, and nanowire ring illumination microscopy based on spatial frequency shift effect. The bottlenecks of the current techniques and possible solutions are also discussed.展开更多
Spherical aberrations of the thermal lens of the active media are severe when solid state lasers are strongly pumped. The fundamental mode profile deteriorates due to the aberrations. Self-consistent modes of a resona...Spherical aberrations of the thermal lens of the active media are severe when solid state lasers are strongly pumped. The fundamental mode profile deteriorates due to the aberrations. Self-consistent modes of a resonator with aberrations are calculated by using the Fox-Li diffraction iterative algorithm. Calculation results show that the aberration induced fundamental mode beam quality deterioration depends greatly on the resonator design. The tolerance of a flat-flat resonator to the aberration coefficient is about 30λ in the middle of stability, where λ is the wavelength of laser beam. But for a dynamically stable resonator, 2λ of spherical aberration will create diffraction loss of more than 40%, if inappropriate design criteria are used. A birefringence compensated laser resonator with two Nd：YAG rods is experimentally studied. The experimental data are in quite good agreement with simulation results.展开更多
Anomalous long-time increase of the diffraction efficiency is observed in dark-decay experiments of photorefractive gratings in Ce：BaTiO3. It is deduced that a phase-conjugate beam is induced by the writing beam at a...Anomalous long-time increase of the diffraction efficiency is observed in dark-decay experiments of photorefractive gratings in Ce：BaTiO3. It is deduced that a phase-conjugate beam is induced by the writing beam at acute angle to the ＋c axis of the crystal and it interferes with the other writing beam to form a second grating which is perpendicular to the first grating formed by the interference between two writing beams. The rising behaviour of the diffraction efficiency results from the different decay rates of these two photorefractive gratings. Furthermore, a simplified model of two gratings, both induced by two deep traps, is proposed to account for this phenomenon and the fitting results agree well with the experimental results.展开更多
When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show ...When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.展开更多
Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by ...Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by the topological mechanics of knots,we construct optical fiber knot(OFN)sensors for slip detection and friction measurement.By introducing localized self-contacts along the fiber,the knot structure enables anisotropic responses to normal and frictional forces.By employing OFNs and a change point detection algorithm,we demonstrate adaptive robotic grasping of slipping cups.We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs.Such a tactile finger allows a robotic hand to manipulate human tools dexterously.This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping,dexterous manipulation,and human-robot interaction with tactile sensing.展开更多
Tunable radiation with a linewidth of 0.014 nm was obtained in Rhodamine B,Rhodamine 6G,Perylene orange and Pyrromethene 567-doped GPTMS solid-state dye materials using intracavity grating dispersive oscillation.The s...Tunable radiation with a linewidth of 0.014 nm was obtained in Rhodamine B,Rhodamine 6G,Perylene orange and Pyrromethene 567-doped GPTMS solid-state dye materials using intracavity grating dispersive oscillation.The solid dye samples were specially designed in the way in which they are gelling,drying and ageing between two anti-reflection coated disks,thus without any mechanical and optical processing.The conversion efficiency of 4.6%and the tunable range of 40 nm from 589-629 nm have been achieved in Rhodamine B-doped samples.The broadband lasing of 4.4 nm and 54%slope efficiency were also demonstrated in the experiment.展开更多
An equivalent particle size distribution function n(r)is applied to describe optical scattering property of tissue.Under the Fraunhofer diffraction approximation,both the scattering coefficientμs and the scattering p...An equivalent particle size distribution function n(r)is applied to describe optical scattering property of tissue.Under the Fraunhofer diffraction approximation,both the scattering coefficientμs and the scattering phase function S(θ)are educible from n(r).Moreover,such a scheme provides a new feasible method based on the light scattering techniques for particle size analysis to measure the optical properties of tissue.Experimental results of the whole human blood and a thin porcine muscle sample are also provided and so is a calculation resulting from an optical phantom of tissue.The light scattering equivalency between the practical tissue and the corresponding equivalent particles has been verified.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 60425517 and 60378036.
文摘Near-field scanning optical microscopy is used to investigate the waveguiding properties of optical micro/nanofibres （MNFs） by means of detecting optical power carried by evanescent waves. Taper drawn silica and tellurite MNFs, supported on low-index substrates, are used to guide a 532-nm-wavelength light beam for the test. Modification of the single-mode condition of the MNF in the presence of a substrate is observed. Spatial modulation of the longitudinal field intensity （with a 195-nm period） near the output end of a 760-nm-diameter silica MNF is well resolved. Energy exchange through evanescent coupling between two parallel MNFs is also investigated.
基金Supported by the National Natural Science Foundation of China under Crant No 60407003, and the National Basic Research Program of China under Grant No 2007CB307003.
文摘The multimode evolution, optical losses and wavelength response of non-adiabatic micro/nano-fiber （MNF） tapers are numerically simulated using a three-dimensional finite-difference beam propagation method. For a non-adiabatic MNF taper, it is illustrated that optical losses vary with the transition region length and the optical wavelength. We explain how the complicated multimode evolutions result in the complicated optical loss and wavelength response properties, especially when the waist diameters are large enough to allow much higher-order modes. These results may offer valuable references for trapping and guiding cold atoms in atom optics and practical application of micro/nano-devices.
基金This work was supported by the National Key Research and Development Program of China(2016YFB1001300)the National Natural Science Foundation of China(No.11527901)the Fundamental Research Funds for the Central Universities.
文摘Electronic skin,a class of wearable electronic sensors that mimic the functionalities of human skin,has made remarkable success in applications including health monitoring,human-machine interaction and electronic-biological interfaces.While electronic skin continues to achieve higher sensitivity and faster response,its ultimate performance is fundamentally limited by the nature of low-frequency AC currents.Herein,highly sensitive skin-like wearable optical sensors are demonstrated by embedding glass micro/nanofibers(MNFs)in thin layers of polydimethylsiloxane(PDMS).Enabled by the transition from guided modes into radiation modes of the waveguiding MNFs upon external stimuli,the skin-like optical sensors show ultrahigh sensitivity(1870 k·Pa^-1),low detection limit(7 mPa)and fast response(10μs)for pressure sensing,significantly exceeding the performance metrics of state-of-the-art electronic skins.Electromagnetic interference(EMI)-free detection of high-frequency vibrations,wrist pulse and human voice are realized.Moreover,a five-sensor optical data glove and a 2×2-MNF tactile sensor are demonstrated.These initial results pave the way toward a new category of optical devices ranging from ultrasensitive wearable sensors to optical skins.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10334050 and 10547183, and the Scientific Research Foundation for Returned 0verseas Chinese Scholars of Zhejiang Province （G80611）.
文摘A generalized formula of hollow Gaussian beams through the first-order misaligned ABCD systems is derived by using the generalized diffraction integral formula. It is shown that the hollow Gaussian beam passing through the misaligned system becomes a decentred hollow Gaussian beam. The propagation properties of the output beam are investigated when it propagates through a simple misaligned lens system. These results provide a powerful theoretical tool for applications of optical traps.
文摘A new organic-inorganic hybrid material doped with BDK that exhibits a large photo-induced change in optical properties is prepared by the sol-gel method.The photosensitivity of the film under ultraviolet irradiation is investigated with various exposure times.An increase in refractive index from 1.558 to 1.592 atλ=550 nm is observed together with a 57.3%expansion in physical thickness.The film's optical thickness exhibits an exponential change with the irradiation time.The photo-decomposition of BDK organic groups confirmed by the infrared absorption spectrum contributes to the photosensitive mechanism.A first example of photo-patterning is finally presented by direct light writing.
基金We are grateful for financial supports from the National Natural Science Foundation of China(No.61975173)the National Key Research and Development Program of China(No.SQ2019YFC170311)+3 种基金the Major Scientific Research Project of Zhejiang Lab(No.2019MC0AD01)the Key Research and Development Project of Zhejiang Province(No.2021C05003)the Quantum Joint Funds of the Natural Foundation of Shandong Province(No.ZR2020LLZ007)the CIE-Tencent Robotics X Rhino-Bird Focused Research Program(No.2020-01-006).
文摘Flexible strain sensors play an important role in electronic skins,wearable medical devices,and advanced robots.Herein,a highly sensitive and fast response optical strain sensor with two evanescently coupled optical micro/nanofibers(MNFs)embedded in a polydimethylsiloxane(PDMS)film is proposed.The strain sensor exhibits a gauge factor as high as 64.5 for strain≤0.5%and a strain resolution of 0.0012%which corresponds to elongation of 120 nm on a 1 cm long device.As a proof-of-concept,highly sensitive fingertip pulse measurement is realized.The properties of fast temporal frequency response up to 30 kHz and a pressure sensitivity of 102 kPa^(−1) enable the sensor for sound detection.Such versatile sensor could be of great use in physiological signal monitoring,voice recognition and micro-displacement detection.
基金supports from the National Key R&D Program of China (No. 2021YFB2802000 and 2021YFB2800500)the National Natural Science Foundation of China (Grant Nos. U20A20211, 51902286, 61775192, 61905215, and 62005164)+2 种基金Key Research Project of Zhejiang Labthe State Key Laboratory of High Field Laser Physics (Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences)China Postdoctoral Science Foundation (2021M702799)。
文摘Long-term optical data storage(ODS)technology is essential to break the bottleneck of high energy consumption for information storage in the current era of big data.Here,ODS with an ultralong lifetime of 2×10^(7)years is attained with single ultrafast laser pulse induced reduction of Eu^(3+)ions and tailoring of optical properties inside the Eu-doped aluminosilicate glasses.We demonstrate that the induced local modifications in the glass can stand against the temperature of up to 970 K and strong ultraviolet light irradiation with the power density of 100 kW/cm^(2).Furthermore,the active ions of Eu^(2+)exhibit strong and broadband emission with the full width at half maximum reaching 190 nm,and the photoluminescence(PL)is flexibly tunable in the whole visible region by regulating the alkaline earth metal ions in the glasses.The developed technology and materials will be of great significance in photonic applications such as long-term ODS.
基金financial supports from the National Natural Science Foundation of China(Grant Nos.62174073,61875073,11674130,91750110 and 61522504)the National Key R&D Program of China(Grant No.2018YFB1107200)+3 种基金the Guangdong Provincial Innovation and Entrepren-eurship Project(Grant No.2016ZT06D081)the Natural Science Founda-tion of Guangdong Province,China(Grant Nos.2016A030306016 and 2016TQ03X981)the Pearl River Nova Program of Guangzhou(Grant No.201806010040)the Technology Innovation and Development Plan of Yantai(Grant No.2020XDRH095).
文摘Encoding information in light polarization is of great importance in facilitating optical data storage(ODS)for information security and data storage capacity escalation.However,despite recent advances in nanophotonic techniques vastly en-hancing the feasibility of applying polarization channels,the data fidelity in reconstructed bits has been constrained by severe crosstalks occurring between varied polarization angles during data recording and reading process,which gravely hindered the utilization of this technique in practice.In this paper,we demonstrate an ultra-low crosstalk polarization-en-coding multilayer ODS technique for high-fidelity data recording and retrieving by utilizing a nanofibre-based nanocom-posite film involving highly aligned gold nanorods(GNRs).With parallelizing the gold nanorods in the recording medium,the information carrier configuration minimizes miswriting and misreading possibilities for information input and output,respectively,compared with its randomly self-assembled counterparts.The enhanced data accuracy has significantly im-proved the bit recall fidelity that is quantified by a correlation coefficient higher than 0.99.It is anticipated that the demon-strated technique can facilitate the development of multiplexing ODS for a greener future.
基金Project supported by the Science and Technology Major Projects of Zhejiang Province,China(Grant No.2013C03043-5)
文摘Digital structured light （SL） profilometry is increasingly used in three-dimensional （3D） measurement technology. However, the nonlinearity of the off-the-shelf projectors and cameras seriously reduces the measurement accuracy. In this paper, first, we review the nonlinear effects of the projector-camera system in the phase-shifting structured light depth measurement method. We show that high order harmonic wave components lead to phase error in the phase-shifting method. Then a practical method based on frequency domain filtering is proposed for nonlinear error reduction. By using this method, the nonlinear calibration of the SL system is not required. Moreover, both the nonlinear effects of the projector and the camera can be effectively reduced. The simulations and experiments have verified our nonlinear correction method.
基金Supported by the Research Foundation of Science and Technology Department of Zhejiang Province(2009C21023).
文摘In this Letter we outline a dielectric multilayer spectrally selective filter designed for solar energy applications.The optical performance of this 78-layer interference filter constructed by TiOx and SiO_(2) is presented.A hybrid system combining photovoltaic cells with a solar-powered Stirling engine using the designed filter is analyzed.The calculated results show the advantages of this spectrally selective method for solar power generation.
基金We are grateful for financial supports from the National Natural Science Foundation of China(No.61975173)the Major Scientific Research Project of Zhejiang Lab(No.2019MC0AD01)the Key Research and Development Project of Zhejiang Province(No.2021C05003,2022C03103)。
文摘Flexible optical sensors have been an emerging paradigm for applications in robotics,healthcare,and human–machine interfaces due to their high sensitivity,fast response,and anti-electromagnetic interference.Recently,Marques reports a bioinspired multifunctional flexible optical sensor(BioMFOS),achieving a forces sensitivity of 13.28μN,and a spatial resolution of 0.02 mm.The BioMFOS has a small dimension(around 2 cm)and a light weight(0.8 g),making it suitable for wearable application and clothing integration.As proof-of-concept demonstrations,monitoring of finger position,trunk movements,and respiration rate are realized,implying their prominent applications in remote healthcare,intelligent robots,assistance devices teleoperation,and human-machine interfaces.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60708006 and 60978026, the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20070335118, and the Zhejiang Provincial Natural Science Foundation of China under Grant No Y1090379.
文摘We experimentally demonstrate the C-band wavelength conversion using four-wave mixing in a 17-mm-long silicon-on-insulator waveguide pumped by a dispersed mode-locked femtosecond laser pulse. The idler can be observed with an incident average pump power lower than 4 dBm, and about 35 nm of conversion bandwidth from 1530nm to 1565nm is measured by using a 1550-nm pump wavelength. The pulse-pumped efficiency is demonstrated to be higher, by more than 22 dB, than the cw-pumped efficiency. The conversion efficiency variations with respect to the pump and signal powers are also investigated.
基金financial supports from the National Key R&D Program of China(No.2021YFB2800500)the National Natural Science Foundation of China(Grant Nos.U20A20211,51902286)Key Research Project of Zhejiang Lab.
文摘The past two decades have seen a drastic progress in the development of semiconducting metal-halide perovskites(MHPs)from both the fundamentally scientific and technological points of view.The excellent optoelectronic properties and device performance make perovskites very attractive to the researchers in materials,physics,chemistry and so on.To fully explore the potential of perovskites in the applications,various techniques have been demonstrated to synthesize perovskites,modify their structures,and create patterns and devices.Among them,photo-processing has been revealed to be a facile and general technique to achieve these aims.In this review,we discuss the mechanisms of photo-processing of perovskites and summarize the recent progress in the photo-processing of perovskites for synthesis,patterning,ion exchange,phase transition,assembly,and ion migration and redistribution.The applications of photo-processed perovskites in photovoltaic devices,lasers,photodetectors,light-emitting diodes(LEDs),and optical data storage and encryption are also discussed.Finally,we provide an outlook on photo-processing of perovskites and propose the promising directions for future researches.This review is of significance to the researches and applications of perovskites and also to uncover new views on the light-matter interactions.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61735017 and 51672245)the Zhejiang Provincial Natural Science Foundation of China(Grant No.R17F050003)+4 种基金the National Key Basic Research Program of China(Grant No.2015CB352003)the Fundamental Research Funds for the Central Universities,Chinathe Program for Zhejiang Leading Team of S&T Innovation,Chinathe Cao Guangbiao Advanced Technology Program,ChinaFirst-class Universities and Academic Programs,China
文摘Super resolution imaging capable of resolving details beyond the diffraction limit is highly desired in many scientific and application fields, including bio-medicine, nanomaterial science, and opto-electronic integration. Up to now, many different methods have been proposed, among which wide-field, label-free super resolution microscopy is indispensable due to its good applicability to diverse sample types, large field of view（FOV）, and high imaging speed. In recent years,nanostructures have made a crucial contribution to the wide-field, label-free subdiffraction microscopy, with various working mechanisms and configuration designs. This review summarizes the recent applications of the nanostructures in the wide-field, label-free super resolution microscopy, with the emphasis on the designs of hyperlens with hyperbolic dispersion, microsphere with ＂nano-jets＂, and nanowire ring illumination microscopy based on spatial frequency shift effect. The bottlenecks of the current techniques and possible solutions are also discussed.
基金Project supported by the National Natural Science Foundation-the Science Foundation of China Academy of Engineering Physics(NSAF) (Grant No 10876037)China Postdoctoral Science Foundation (Grant No 20080441238)
文摘Spherical aberrations of the thermal lens of the active media are severe when solid state lasers are strongly pumped. The fundamental mode profile deteriorates due to the aberrations. Self-consistent modes of a resonator with aberrations are calculated by using the Fox-Li diffraction iterative algorithm. Calculation results show that the aberration induced fundamental mode beam quality deterioration depends greatly on the resonator design. The tolerance of a flat-flat resonator to the aberration coefficient is about 30λ in the middle of stability, where λ is the wavelength of laser beam. But for a dynamically stable resonator, 2λ of spherical aberration will create diffraction loss of more than 40%, if inappropriate design criteria are used. A birefringence compensated laser resonator with two Nd：YAG rods is experimentally studied. The experimental data are in quite good agreement with simulation results.
基金Project supported by the National Natural Science Foundation of China （Grant No 60078002）,
文摘Anomalous long-time increase of the diffraction efficiency is observed in dark-decay experiments of photorefractive gratings in Ce：BaTiO3. It is deduced that a phase-conjugate beam is induced by the writing beam at acute angle to the ＋c axis of the crystal and it interferes with the other writing beam to form a second grating which is perpendicular to the first grating formed by the interference between two writing beams. The rising behaviour of the diffraction efficiency results from the different decay rates of these two photorefractive gratings. Furthermore, a simplified model of two gratings, both induced by two deep traps, is proposed to account for this phenomenon and the fitting results agree well with the experimental results.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.11934010,U1801661,and 12174329)the Zhejiang Province Program for Science and Technology(Grant No.2020C01019)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2021FZZX001-02)the China Postdoctoral Science Foundation(Grant No.2019M660137)
文摘When there is a certain amount of field inhomogeneity,the biased ferrimagnetic crystal can exhibit the higher-order magnetostatic(HMS)mode in addition to the uniform-precession Kittel mode.In cavity magnonics,we show the nonlinearity and heating-induced frequency shifts of the Kittel mode and HMS mode in a yttrium-iron-garnet(YIG)sphere.When the Kittel mode is driven to generate a certain number of excitations,the temperature of the whole YIG sample rises and the HMS mode can display an induced frequency shift,and vice versa.This cross effect provides a new method to study the magnetization dynamics and paves a way for novel cavity magnonic devices by including the heating effect as an operational degree of freedom.
基金grateful for financial supports from National Natural Science Foundation of China(61975173)China Postdoctoral Science Foundation(2022M722907,2022M722909)+2 种基金Zhejiang Provincial Natural Science Foundation of China(LQ23F010015)Key Research and Development Project of Zhejiang Province(2021C05003)Major Scientific Research Project of Zhejiang Lab(2019MC0AD01).
文摘Friction plays a critical role in dexterous robotic manipulation.However,realizing friction sensing remains a challenge due to the difficulty in designing sensing structures to decouple multi-axial forces.Inspired by the topological mechanics of knots,we construct optical fiber knot(OFN)sensors for slip detection and friction measurement.By introducing localized self-contacts along the fiber,the knot structure enables anisotropic responses to normal and frictional forces.By employing OFNs and a change point detection algorithm,we demonstrate adaptive robotic grasping of slipping cups.We further develop a robotic finger that can measure tri-axial forces via a centrosymmetric architecture composed of five OFNs.Such a tactile finger allows a robotic hand to manipulate human tools dexterously.This work could provide a straightforward and cost-effective strategy for promoting adaptive grasping,dexterous manipulation,and human-robot interaction with tactile sensing.
基金Supported by the National Natural Science Foundation of China under Grant No.69890230the Opening Research Foundation of State Key Laboratory of Modern Optical Instrumentation.
文摘Tunable radiation with a linewidth of 0.014 nm was obtained in Rhodamine B,Rhodamine 6G,Perylene orange and Pyrromethene 567-doped GPTMS solid-state dye materials using intracavity grating dispersive oscillation.The solid dye samples were specially designed in the way in which they are gelling,drying and ageing between two anti-reflection coated disks,thus without any mechanical and optical processing.The conversion efficiency of 4.6%and the tunable range of 40 nm from 589-629 nm have been achieved in Rhodamine B-doped samples.The broadband lasing of 4.4 nm and 54%slope efficiency were also demonstrated in the experiment.
基金Supported by the Opening Project of the State Key Laboratory of Modern Optical Instrumentation,Zhejiang University under Grant No.LMOI-9808the National Natural Science Foundation of China under Grant No.69778029.
文摘An equivalent particle size distribution function n(r)is applied to describe optical scattering property of tissue.Under the Fraunhofer diffraction approximation,both the scattering coefficientμs and the scattering phase function S(θ)are educible from n(r).Moreover,such a scheme provides a new feasible method based on the light scattering techniques for particle size analysis to measure the optical properties of tissue.Experimental results of the whole human blood and a thin porcine muscle sample are also provided and so is a calculation resulting from an optical phantom of tissue.The light scattering equivalency between the practical tissue and the corresponding equivalent particles has been verified.
