Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the...Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the near-field optical polar- ization response at the edge of a triangular gold nanosheet, which is synthesized by a wet chemical method. A homemade scanning near-field optical microscope （SNOM） in collection mode is adopted, which is able to accurately locate its probe at the edge during experiments. An uncoated straight fiber probe is used in the SNOM, because it s611 preserves the prop- erty of light polarization though it has the depolarization to some extent. By comparing near-field intensities at the edge and glass substrate, detected in different polarization directions of incident light, the edge-induced depolarization is found, which is supported by the finite differential time domain （FDTD） simulated results. The depolarized phenomenon in the near-field is similar to that in the far-field.展开更多
We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SN...We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SNOM image contrast between the two sides of the step changes periodically at different scan heights. For a step height of-λ/2, the image contrast remains approximately the same. The probe-sample interaction determines the SNOM image contrast here. The influence of different refractive indices of the sample has been also analysed by using a simple theoretical model.展开更多
Utilizing reflection-based near-field scanning optical microscopy(NSOM) to image and analyze standing-wave patterns, we present a characterization technique potentially suitable for complex photonic integrated circuit...Utilizing reflection-based near-field scanning optical microscopy(NSOM) to image and analyze standing-wave patterns, we present a characterization technique potentially suitable for complex photonic integrated circuits. By raster scanning along the axis of a straight nano-waveguide in tapping mode and sweeping wavelength, detailed information of propagating waves in that waveguide has been extracted from analyses in both space and wavelength domains. Our technique needs no special steps for phase stabilization, thus allowing long-duration and environment-insensitive measurements. As a proof-of-concept test, in a silicon single-mode waveguide with a few of etched holes, the locations and reflection strengths of the inner defects have been quantified. The measurement uncertainty of the reflection amplitude is less than 25% at current stage. Our technique paves the way for non-destructively diagnosing photonic circuits on a chip with sub-wavelength spatial resolution and detailed information extraction.展开更多
Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and f...Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.展开更多
A scanning near-field optical microscope using uncoated fiber tipis described, which can work in transmission and reflectionconfigurations, both capable of working in illumination andcollection-mode, so that either tr...A scanning near-field optical microscope using uncoated fiber tipis described, which can work in transmission and reflectionconfigurations, both capable of working in illumination andcollection-mode, so that either transparent of opaque sample can beinvestigated. Depending on different applications, eitherconstant-gap or constant-height images can be achieved. A compacthomemade translator permits to elect interested area of sample in therange of 4 mm×4 mm.展开更多
We use the couple dipole method to investigate the scanning near-field optical microscopy metallic tip-nanoparticle near-field interaction. Dependences of the local field intensity inside the nanoparticle on the nanos...We use the couple dipole method to investigate the scanning near-field optical microscopy metallic tip-nanoparticle near-field interaction. Dependences of the local field intensity inside the nanoparticle on the nanosized tip shape,the tip open angle and the illumination angle are revealed. In combination with the previous results, we establish a complete model to understand the tip-nanoparticle near-field coupling mechanism.展开更多
The design and characterization of a tip control unit for an apertureless scanning near field optical microscope (ASNOM) is reported. To make the instrument operation easier, the cantilever control parts (piezo excita...The design and characterization of a tip control unit for an apertureless scanning near field optical microscope (ASNOM) is reported. To make the instrument operation easier, the cantilever control parts (piezo excitation of the cantilever vibration for the dynamic mode feedback and the parts necessary for the optical lever scheme of the vibration control) were placed in a separate detachable assembly. To suppress the influence of vibrations of the setup, the assembly was made lightweight. Good optical access to the ASNOM tip from various directions is provided in the system. High long-term mechanical stability of the system (~50 nm lateral drift in 18 hours) as well as low sensitivity to seismic vibrations (~400 pm RMS) is demonstrated. It is shown that external sound is not a main source of noise in the topography image (~200 pm RMS). The light field distribution (with its amplitude and phase) around the ASNOM tip was acquired by scanning the focal spot around the tip, and a high optical quality of the system is demonstrated.展开更多
ZnO films are deposited on glass slides by radio frequency(RF) magnetron sputtering under different powers. The polycrystal structures and surface morphologies of the film are investigated. The optical transmission sp...ZnO films are deposited on glass slides by radio frequency(RF) magnetron sputtering under different powers. The polycrystal structures and surface morphologies of the film are investigated. The optical transmission spectra for the ZnO films are measured within the range from 300 nm to 800 nm. The optical constants and thickness of the films are determined using a nonlinear programming method suggested by Birgin et al. The band gap of the film increases with reducing the nano-size of the film grains. The packing density of the films can be improved by reducing the RF power.展开更多
The clusters of Eu^3＋ ion in Eu（DBM）3Phen-doped polymethyl methacrylate （PMMA） have been studied by three means. The relative fluorescence intensity ratio of the ^5D0 → ^7F2 to ^5D0 → ^7F1 transitions with diff...The clusters of Eu^3＋ ion in Eu（DBM）3Phen-doped polymethyl methacrylate （PMMA） have been studied by three means. The relative fluorescence intensity ratio of the ^5D0 → ^7F2 to ^5D0 → ^7F1 transitions with different concentrations of Eu^3＋ in Eu（DBM）3Phen-doped PMMA and metastable-state （^5D0） lifetime dependence on Eu^3＋ concentration axe analyzed. The analysis indicates that there axe no clustering effects in Eu^3＋ ions of Eu（DBM）3Phen-doped PMMA when the Eu^3＋ doping concentration is up to 1.0 wt.-%. At the same time, the clustering effect has not been observed by the scanning neax-field optical microscopy （SNOM） in Eu（DBM）3Phen-doped PMMA with 1.0 wt.-% of Eu^3＋ ions. The analysis reveals that a high concentration of Eu^3＋ can be incorporated into polymer optical fiber （POF） without clustering effect.展开更多
In the present work Pure and Cobalt (Co) doped Zinc Oxide (ZnO) Nanoparticles were synthesized by Sol-gel method. The effect of Co doping on structural and optical properties of Nanoparticles were investigated using X...In the present work Pure and Cobalt (Co) doped Zinc Oxide (ZnO) Nanoparticles were synthesized by Sol-gel method. The effect of Co doping on structural and optical properties of Nanoparticles were investigated using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopic characterization techniques. The XRD spectrum revealed the formation of Wurtzite structure of ZnO. The structural properties of nanoparticles including particle size and lattice strain were calculated from XRD data. SEM shows the morphology of Nanoparticles. The presence of functional groups was analyzed from FTIR spectra. The properties of Cobalt doped zinc oxide nanoparticles prepared through simple cost effective, Sol-gel method can be used in optoelectronics and thermally stable devices.展开更多
The BL08U1 A beamline is established as a sophisticated platform at Shanghai Synchrotron Radiation Facility(SSRF), taking advantage of its high spatial resolution(< 30 nm) and high energy resolving power(>10 000...The BL08U1 A beamline is established as a sophisticated platform at Shanghai Synchrotron Radiation Facility(SSRF), taking advantage of its high spatial resolution(< 30 nm) and high energy resolving power(>10 000),for studying properties of solid, liquid, gas, film and other forms of materials at sub-micron scale. In this paper,we present a review on newly implemented techniques, such as total electron yield(TEY), dual energy contrast imaging, nano-CT, soft X-ray excited optical luminance(SXEOL), and coherent diffraction imaging(CDI)under development. Several research cases in nanomaterials, environmental science and biology are presented to demonstrate capabilities of the beamline.展开更多
Microstructure and variations in porosity in Ti-6Al-4V samples built with electron beam melting (EBM) over a range of melt scan speeds, ranging from 100 mm·s-1 to 1000 mm·s-1 were examined. Microstructure wa...Microstructure and variations in porosity in Ti-6Al-4V samples built with electron beam melting (EBM) over a range of melt scan speeds, ranging from 100 mm·s-1 to 1000 mm·s-1 were examined. Microstructure was characterized by refinement of α-phase and transformation to α′-martensite. Light optical microscopy, scanning electron microscopy, and transmission electron microscopy were used to observe these phenomena, while corresponding tensile testing and associated macro and microindentation hardness measurements were used to define the microstructural variations. Relative stiffness was observed to be linearly log-log related to relative density, corresponding to ideal porosity associated with open-cellular structures.展开更多
The optical waveguide behaviors of CdS and CdSxSe1?x nanostructures are studied using near-field optical microscopy. Optical measurements demonstrate that light may be guided on sub-wavelength scales along CdS nanorib...The optical waveguide behaviors of CdS and CdSxSe1?x nanostructures are studied using near-field optical microscopy. Optical measurements demonstrate that light may be guided on sub-wavelength scales along CdS nanoribbons in straight or bent structures. The photoluminescence (PL) spectra from nanoribbon emission using scanning near-field optical microscopy are analyzed under different incident laser intensities. The PL spectra along Se-doped and undoped CdS nanoribbons at different propagation distances are investigated. Both the guided PL spectra of Se-doped and undoped CdS nanoribbons show red-shifts because of the band-edge absorption. Our results are useful for the development of new kinds of functional nano devices.展开更多
The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute opti...The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray). Exploration by these techniques of a blood stain located on the face permits us to discover some red-colour particles (hematite, biotite and cinnabar) of exogenous material in this stain. We finally characterize these red-colour particles and try to explain their presences in the blood stain. Globally, all these red-colour particles cannot explain all of the reddish appearance of the area under study.展开更多
Scanning near-field optical microscopy （SNOM） is an ideal experimental measuring system in nano-optical measurements and characterizations. Besides microscopy with resolution beyond the diffraction limit, spectrosco...Scanning near-field optical microscopy （SNOM） is an ideal experimental measuring system in nano-optical measurements and characterizations. Besides microscopy with resolution beyond the diffraction limit, spectroscope with nanometer resolution and other instruments with novel performances have been indispensable for researches in nano-optics and nanophotonics. This paper reviews the developing history of near-field optical （NFO） measuring method and foresees its prospects in future. The development of NFO measurements has gone through four stages, including optical imaging with super resolution, near-field spectroscopy, measurements ofnanooptical parameters, and detections of near-field interac- tions. For every stage, research objectives, technological properties and application fields are discussed.展开更多
基金Project supported by the National Key Basic Research Program of China(Grant No.2013CB934004)the Fundamental Research Funds for the Central Universities,China(Grant No.YWF-13-D2-XX-14)
文摘Optical properties of metallic edge-like structures known as knife-edges are a topic of interest and possess potential applications in enhanced Raman scattering, optical trapping, etc. In this work, we investigate the near-field optical polar- ization response at the edge of a triangular gold nanosheet, which is synthesized by a wet chemical method. A homemade scanning near-field optical microscope （SNOM） in collection mode is adopted, which is able to accurately locate its probe at the edge during experiments. An uncoated straight fiber probe is used in the SNOM, because it s611 preserves the prop- erty of light polarization though it has the depolarization to some extent. By comparing near-field intensities at the edge and glass substrate, detected in different polarization directions of incident light, the edge-induced depolarization is found, which is supported by the finite differential time domain （FDTD） simulated results. The depolarized phenomenon in the near-field is similar to that in the far-field.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 90206003, 10374005, 10434020, 10521002, 10328407 and 90101027） and the Research Fund for the Doctoral Program of Higher Education of China （Grant No 20040001012）.
文摘We have studied the influence of probe-sample interaction in a scanning near-field optical microscopy （SNOM） in the far field by using samples with a step structure. For a sample with a step height of - λ/4, the SNOM image contrast between the two sides of the step changes periodically at different scan heights. For a step height of-λ/2, the image contrast remains approximately the same. The probe-sample interaction determines the SNOM image contrast here. The influence of different refractive indices of the sample has been also analysed by using a simple theoretical model.
基金Project supported by National Key R&D Program of China(Grant No.2017YFA0303800)National Natural Science Foundation of China(Grant No.61575218)Defense Industrial Technology Development Program,China(Grant No.JCKY201601C006)
文摘Utilizing reflection-based near-field scanning optical microscopy(NSOM) to image and analyze standing-wave patterns, we present a characterization technique potentially suitable for complex photonic integrated circuits. By raster scanning along the axis of a straight nano-waveguide in tapping mode and sweeping wavelength, detailed information of propagating waves in that waveguide has been extracted from analyses in both space and wavelength domains. Our technique needs no special steps for phase stabilization, thus allowing long-duration and environment-insensitive measurements. As a proof-of-concept test, in a silicon single-mode waveguide with a few of etched holes, the locations and reflection strengths of the inner defects have been quantified. The measurement uncertainty of the reflection amplitude is less than 25% at current stage. Our technique paves the way for non-destructively diagnosing photonic circuits on a chip with sub-wavelength spatial resolution and detailed information extraction.
基金supported by the National Natural Science Foundation of China(Grant Nos.61177089,61227014,and 60978047)
文摘Phase is one of the most important parameters of electromagnetic waves. It is the phase distribution that determines the propagation, reflection, refraction, focusing, divergence, and coupling features of light, and further affects the intensity distribution. In recent years, the designs of surface plasmon polariton （SPP） devices have mostly been based on the phase modulation and manipulation. Here we demonstrate a phase sensitive multi-parameter heterodyne scanning near-field opti- cal microscope （SNOM） with an aperture probe in the visible range, with which the near field optical phase and amplitude distributions can be simultaneously obtained. A novel architecture combining a spatial optical path and a fiber optical path is employed for stability and flexibility. Two kinds of typical nano-photonic devices are tested with the system. With the phase-sensitive SNOM, the phase and amplitude distributions of any nano-optical field and localized field generated with any SPP nano-structures and irregular phase modulation surfaces can be investigated. The phase distribution and the interference pattern will help us to gain a better understanding of how light interacts with SPP structures and how SPP waves generate, localize, convert, and propagate on an SPP surface. This will be a significant guidance on SPP nano-structure design and optimization.
文摘A scanning near-field optical microscope using uncoated fiber tipis described, which can work in transmission and reflectionconfigurations, both capable of working in illumination andcollection-mode, so that either transparent of opaque sample can beinvestigated. Depending on different applications, eitherconstant-gap or constant-height images can be achieved. A compacthomemade translator permits to elect interested area of sample in therange of 4 mm×4 mm.
基金Supported by the Start-Up Grant of Zhejiang University of Technology,the Zhejiang Provincial Key Laboratory of Information Processing,Communication and Networking,the Zhejiang University,and the National Natural Science Foundation of China under Grant No 61605171
文摘We use the couple dipole method to investigate the scanning near-field optical microscopy metallic tip-nanoparticle near-field interaction. Dependences of the local field intensity inside the nanoparticle on the nanosized tip shape,the tip open angle and the illumination angle are revealed. In combination with the previous results, we establish a complete model to understand the tip-nanoparticle near-field coupling mechanism.
文摘The design and characterization of a tip control unit for an apertureless scanning near field optical microscope (ASNOM) is reported. To make the instrument operation easier, the cantilever control parts (piezo excitation of the cantilever vibration for the dynamic mode feedback and the parts necessary for the optical lever scheme of the vibration control) were placed in a separate detachable assembly. To suppress the influence of vibrations of the setup, the assembly was made lightweight. Good optical access to the ASNOM tip from various directions is provided in the system. High long-term mechanical stability of the system (~50 nm lateral drift in 18 hours) as well as low sensitivity to seismic vibrations (~400 pm RMS) is demonstrated. It is shown that external sound is not a main source of noise in the topography image (~200 pm RMS). The light field distribution (with its amplitude and phase) around the ASNOM tip was acquired by scanning the focal spot around the tip, and a high optical quality of the system is demonstrated.
基金the Ministry of Science and Technology of China(2002CB211807)Science and Technology Project of FujianProvince of China(2005 H043)Science and Technology Novel Project of Xiamen University(XMKJCX20051025)
文摘ZnO films are deposited on glass slides by radio frequency(RF) magnetron sputtering under different powers. The polycrystal structures and surface morphologies of the film are investigated. The optical transmission spectra for the ZnO films are measured within the range from 300 nm to 800 nm. The optical constants and thickness of the films are determined using a nonlinear programming method suggested by Birgin et al. The band gap of the film increases with reducing the nano-size of the film grains. The packing density of the films can be improved by reducing the RF power.
基金This work was supported by the National ScienceFoundation of China (No. 90201013), the Fujian NaturalScience Foundation of China (No. A0510014), and theFujian Educational Department Foundation of China(No. JB03151 and JB04246).
文摘The clusters of Eu^3＋ ion in Eu（DBM）3Phen-doped polymethyl methacrylate （PMMA） have been studied by three means. The relative fluorescence intensity ratio of the ^5D0 → ^7F2 to ^5D0 → ^7F1 transitions with different concentrations of Eu^3＋ in Eu（DBM）3Phen-doped PMMA and metastable-state （^5D0） lifetime dependence on Eu^3＋ concentration axe analyzed. The analysis indicates that there axe no clustering effects in Eu^3＋ ions of Eu（DBM）3Phen-doped PMMA when the Eu^3＋ doping concentration is up to 1.0 wt.-%. At the same time, the clustering effect has not been observed by the scanning neax-field optical microscopy （SNOM） in Eu（DBM）3Phen-doped PMMA with 1.0 wt.-% of Eu^3＋ ions. The analysis reveals that a high concentration of Eu^3＋ can be incorporated into polymer optical fiber （POF） without clustering effect.
文摘In the present work Pure and Cobalt (Co) doped Zinc Oxide (ZnO) Nanoparticles were synthesized by Sol-gel method. The effect of Co doping on structural and optical properties of Nanoparticles were investigated using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopic characterization techniques. The XRD spectrum revealed the formation of Wurtzite structure of ZnO. The structural properties of nanoparticles including particle size and lattice strain were calculated from XRD data. SEM shows the morphology of Nanoparticles. The presence of functional groups was analyzed from FTIR spectra. The properties of Cobalt doped zinc oxide nanoparticles prepared through simple cost effective, Sol-gel method can be used in optoelectronics and thermally stable devices.
基金supported by the National Natural Sci-ence Foundation of China(No.21972083,No.22102129)the Fundamental Research Funds for the Central Universities(GK202102008)+1 种基金the Support Program for top-notch young talents in Shaanxi Province(1511000066)the China Postdoctoral Science Foundation(2021M692615,2022T150528)。
基金Supported by National Natural Science Foundation of China(Nos.11079050,11290165,11305252 and 11205232)Programs of the Chinese Academy of Sciences(Nos.KJCX2-EW-W09 and KJZD-EW-M03)+2 种基金the Open Research Project of the Large Scientific Facility of the Chinese Academy of Sciences:Study on Self-assembly Technology and Nanometer Array with Ultra-high Densitythe National Natural Science Foundation for Outstanding Young Scientists(No.11225527)the Shanghai Academic Leadership Program(No.13XD1404400)
文摘The BL08U1 A beamline is established as a sophisticated platform at Shanghai Synchrotron Radiation Facility(SSRF), taking advantage of its high spatial resolution(< 30 nm) and high energy resolving power(>10 000),for studying properties of solid, liquid, gas, film and other forms of materials at sub-micron scale. In this paper,we present a review on newly implemented techniques, such as total electron yield(TEY), dual energy contrast imaging, nano-CT, soft X-ray excited optical luminance(SXEOL), and coherent diffraction imaging(CDI)under development. Several research cases in nanomaterials, environmental science and biology are presented to demonstrate capabilities of the beamline.
文摘Microstructure and variations in porosity in Ti-6Al-4V samples built with electron beam melting (EBM) over a range of melt scan speeds, ranging from 100 mm·s-1 to 1000 mm·s-1 were examined. Microstructure was characterized by refinement of α-phase and transformation to α′-martensite. Light optical microscopy, scanning electron microscopy, and transmission electron microscopy were used to observe these phenomena, while corresponding tensile testing and associated macro and microindentation hardness measurements were used to define the microstructural variations. Relative stiffness was observed to be linearly log-log related to relative density, corresponding to ideal porosity associated with open-cellular structures.
基金Supported by the National Natural Science Foundation of China (Grant Nos.10574002,90406007,and 50602015)the National Basic Research Program of China (Grant No.2007CB936800)
文摘The optical waveguide behaviors of CdS and CdSxSe1?x nanostructures are studied using near-field optical microscopy. Optical measurements demonstrate that light may be guided on sub-wavelength scales along CdS nanoribbons in straight or bent structures. The photoluminescence (PL) spectra from nanoribbon emission using scanning near-field optical microscopy are analyzed under different incident laser intensities. The PL spectra along Se-doped and undoped CdS nanoribbons at different propagation distances are investigated. Both the guided PL spectra of Se-doped and undoped CdS nanoribbons show red-shifts because of the band-edge absorption. Our results are useful for the development of new kinds of functional nano devices.
文摘The Turin Shroud, recently accessible for hands-on scientific research, is now extensively investigated. Its pinkish red blood stains that seem anomalous ones are studied by modern techniques (notably by resolute optical microscopy and scanning electron microscopy coupled with energy dispersive X-ray). Exploration by these techniques of a blood stain located on the face permits us to discover some red-colour particles (hematite, biotite and cinnabar) of exogenous material in this stain. We finally characterize these red-colour particles and try to explain their presences in the blood stain. Globally, all these red-colour particles cannot explain all of the reddish appearance of the area under study.
基金This research was supported by the National Natural Science Foundation of China （Grant No. 61177089）.
文摘Scanning near-field optical microscopy （SNOM） is an ideal experimental measuring system in nano-optical measurements and characterizations. Besides microscopy with resolution beyond the diffraction limit, spectroscope with nanometer resolution and other instruments with novel performances have been indispensable for researches in nano-optics and nanophotonics. This paper reviews the developing history of near-field optical （NFO） measuring method and foresees its prospects in future. The development of NFO measurements has gone through four stages, including optical imaging with super resolution, near-field spectroscopy, measurements ofnanooptical parameters, and detections of near-field interac- tions. For every stage, research objectives, technological properties and application fields are discussed.
