Journal of Computational and Theoretical Nanoscience, 2019
Inspired by imaging principle of near-field scanning optical microscope (NSOM), meta-pillars arra... more Inspired by imaging principle of near-field scanning optical microscope (NSOM), meta-pillars array is designed and analyzed on the basis of microscopic imaging application with high resolution. Finely focused spots acting as tiny secondary sources for illumination at near-field can be derived under supporting of the meta-pillars for the purpose of increasing imaging resolution. Numerical calculation is carried out on the basis of finite difference and time domain (FDTD) algorithm. Our calculation results demonstrate that the meta-pillars are capable of supporting the microscopic imaging at sub-wavelength resolution.
The anomalous beaming effect of the periodic metallic corrugations functioning as a special case ... more The anomalous beaming effect of the periodic metallic corrugations functioning as a special case of k SP=2π/Λ is discussed and verified by means of both theoretical calculation and experimental probing. A metalens is designed on the basis of the special case. Unlike the conventional beaming of convergence or divergence, the metalens can realize beam collimating, which is useful for practical applications. As a typical application example of the metalens, we integrate the metalens together with a vertical cavity surface emission laser (VCSEL) on the top surface of the aperture area. Our experimental results demonstrate that the integrated metalens is capable of suppressing the divergence angle of the VCSEL for collimation use.
A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array ... more A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array is proposed and developed. The LSPR extinction spectra of the antigen or antibody with lower concentration are detected. The obtained results detected from 100 nM target molecule indicate a larger wavelength shift for the rhombic based nanosensor than the triangular based nanosensor. By experimental detection, we demonstrated that the refractive index sensitivity is 266.2 nm per refractive index unit for Ag rhombic nanoparticle with in-plane width of ∼140 nm and out-of-plane height of 47 nm.
2011 Second International Conference on Mechanic Automation and Control Engineering, 2011
ABSTRACT The ignition of magnesium alloy chips is a problem during high speed dry machining in in... more ABSTRACT The ignition of magnesium alloy chips is a problem during high speed dry machining in industry. It should be avoided in the practical production. Many factors including machining environment, material composition, tool geometry, cutting parameters etc. can influence the cutting processes. Among these factors, cutting parameters is one of most important elements to induce the ignition of magnesium alloys. AM50A is a commercial magnesium alloy which is widely used in industry. However, very few reports about the ignition conditions of AM50A magnesium alloy are available. In this paper, we investigated the ignition conditions of AM50A magnesium alloy at different cutting parameters. The relationship between ignition conditions and chip morphologies was further explored. The macro morphologies of the chips were observed by optical microscope and the micro structure were obtained by scanning electron microscope (SEM). It is found that the macro morphologies of chips can be characterized into powdered chip, tubular helical chip, acicular helical chip, and long belt chip, which correspond to the different ignition conditions. The powdered chips and acicular spiral chips are easily ignited. They have thinner lamellar thickness compared to the other two types of chips. These results may be used to analyze cutting process and prevent the chip ignition in dry machining magnesium alloy.
Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optica... more Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optical properties on account of their surface plasmon resonance (SPR). In this paper, we mainly discussed the theory background of the enhanced optical properties of noble metal nanoparticles. Mie theory, transfer matrix method, discrete dipole approximation (DDA) method, and finite-difference time domain (FDTD) method applied brute-force computational methods for different nanoparticles optical properties. Some important nanostructure fabrication technologies such as nanosphere lithography (NSL) and focused ion beam (FIB) are also introduced in this paper. Moreover, these fabricated nanostructures are used in the plasmonic sensing fields. The binding signal between the antibody and antigen, amyloid-derived diffusible ligands (ADDLs)-potential Alzheimer's disease (AD) biomarkers, and staphylococcal enterotixn B (SEB) in nano-Moore per liter (nM) concentration level are detected by our des...
A biochemistry nanosensor based on hybrid metallic nanostructure array was put forward in this pa... more A biochemistry nanosensor based on hybrid metallic nanostructure array was put forward in this paper. The hybrid metallic nanostructure array consists of two types Ag nanostuctures, spherical and pyramidal structures with the same period. A biochemistry sensor experiment is demonstrated by detecting the transmittance spectra of hybrid metallic nanostructure using Sciencetech spectrophotometer. The wave peaks of transmittance spectra have shifts when the metallic periods and the refractive index of Ag nanostuctures are different.
A Cr adhesion layer inserted between Ag nanoparticles and a glass substrate, for the purpose of i... more A Cr adhesion layer inserted between Ag nanoparticles and a glass substrate, for the purpose of improving the adhesion of Ag nanoparticles to glass, was observed to cause an abnormal peak shift of extinction spectra in nonspecific reactions. The undesired peak shift misleads molecule detection in non-specific reactions. To solve this issue, a practical technique using n-propyl-trimethoxysilane-based passivation for the detection of amyloid-derived diffusible ligands was investigated as a route to eliminate the abnormal peak shifting observed in the non-specific reactions. To evaluate this passivation technique, localized surface plasmon resonance immunoassay experiments were conducted. Experimental results derived with and without the passivation process were investigated as a basis for comparative analysis. Our experimental results demonstrate that this passivation technique effectively eliminates the observed peak shift originating from the Cr adhesion layer.
ABSTRACT The shape of nanostructure array is one of the important parameters for the nanobiosenso... more ABSTRACT The shape of nanostructure array is one of the important parameters for the nanobiosensor applications. In this paper, we focus on the optical properties of silver pentagram nanostructure arrays based on localized surface plasmon resonance (LSPR). This novel nanostructure array has more hot spots than the tradition nanostructure array. Finite-difference and time-domain (FDTD) method was used to design the suitable structure parameters and the localized electric field distribution on the surface of the nanostructures is also explored too. According to the design results, we fabricated the regularly silver pentagram nanostructure array distributed on the surface of the glass substrate using focused ion beam (FIB) nanofabrication method. The calculated and experiment results show that the pentagram nanostructure array can be realized easily by FIB method. The nanostructure array has potential application for the high sensitivity nanobiosensor in the future. KeywordsLocalized surface plasmon resonance–Finite-difference and time-domain–Pentagram nanostructures–Sensitivity
The sensitivity is the most important parameter in the sensing field. Effort was made to study th... more The sensitivity is the most important parameter in the sensing field. Effort was made to study the effect of gold coating on the sensitivity of rhombic silver nanostructure array through numerical simulation using the discrete dipole approximation method. This study shows that thickness of the gold coating can be varied to tune the sensitivity of the rhombic silver nanostructure array. The Au-Ag nanostructure array is found to possess the maximum refractive index sensitivity of 714 nm/RIU when thickness of gold is 20 nm, thickness of silver is 25 nm, and refractive index of the medium is around 1.35. The condition for achieving the maximum refractive index sensitivity can be used for detecting many species of biomolecules and drugs in the future.
A biochemistry nanosensor was put forward on the basis of a new structure: hybrid metallic nanost... more A biochemistry nanosensor was put forward on the basis of a new structure: hybrid metallic nanostructure array (spherical and pyramidal-shaped nanoparticles) in this paper. The hybrid metallic nanostructure array consists of two types of Ag nanostructures: spherical and pyramidal structures patterned with the same period. Design, fabrication and characterization of the Ag nanostructures were presented. Relevant experimental results were obtained by means of detecting the transmittance spectra of the hybrid metallic nanostructure. Apparent shifting of peak wavelength of the transmittance spectra occurs while varies the periods and the effective refractive index of surrounding mediums. Moreover, there are some sharp and narrow peaks of the transmittance spectra by which it can improve the resolving power of the biochemistry nanosensor.
Journal of Computational and Theoretical Nanoscience, 2010
ABSTRACT The sensitivity is one of the most important parameters in the sensing field. Silver tri... more ABSTRACT The sensitivity is one of the most important parameters in the sensing field. Silver triangular nanostructure array is the traditional substrate for detecting the targets. In this paper, we proposed triangular hybrid Au–Ag nanostructure array to be optimized substrate for nanobiosensor. Effort was made to study sensitivity of triangular hybrid Au–Ag nanostructure array through finite-difference time-domain (FDTD) algorithm-based computational numerical calculation method. The extinction efficiency was obtained by theoretical numerical calculation. It is found that the triangular hybrid Au–Ag nanostructure array possess the refractive index sensitivity of 273 nm/RIU when thickness of silver is 40 nm and the gold is 10 nm, and refractive index of the medium is around 1.33. It is higher than the pure silver nanostructure array (242 nm/RIU).
Journal of Computational and Theoretical Nanoscience, 2009
Optimization of metallic nanoparticles was presented in this paper by aid of computational numeri... more Optimization of metallic nanoparticles was presented in this paper by aid of computational numerical calculation. The optical extinction spectra of rhombic hybrid Au-Ag nanoparticles have been calculated by the discrete dipole approximation (DDA) aided design method. Both material and the thickness of the particles can be used to effectively tune localized surface plasmon resonance. On the basis of the calculated extinction spectra, the crucial parameters of the nanostructure arrays such as thickness can be determined. Using this DDA aided approach, a hybrid Au-Ag nanoparticles array is put forth and designed with the optimized parameter of thickness of metal thin films (h Au = 5 nm, and h Ag = 25 nm). This study shows that the material of the particles have significant effect on the optical properties. The DDA aided design method can provide the optimized structure parameters for the hybrid nanostructures.
ABSTRACT We presented a novel optical non-contact measurement system for detection of the thickne... more ABSTRACT We presented a novel optical non-contact measurement system for detection of the thickness and 3D profile of a hybrid film. The optical interference system and the corresponding compiled data processing program for realizing the non-contact detection of thickness and 3D profile of the hybrid metal film were designed. White light source was used to generate the optical interference of the hybrid Au–Ag metallic film. The characteristics of the film were analyzed through the interference fringe. The original color fringe is obtained from a CCD camera, and the Red-Green-Blue (RGB) raw fringe image is put into our compiled numerical program. The fringe phase was wrapped using Fourier transform technique. The unwrapped phase was reconstructed to be the whole-filed Z image and 3D profile by use of a bilateral filter.
In nanofabrication point of view, fabricating a pattern structured with high-aspect ratio nanoa... more In nanofabrication point of view, fabricating a pattern structured with high-aspect ratio nanoantennas and distribution in large area is quite chanllenge. Especially for the structures being used as biochemistry sensors, the sharp nanoantennas with high-aspect ratio is one of an important features. It can form numerous tiny hot spots as small as 50 nm for directional radiation and beaming which is evidenced by our probing results from near-field scanning optical microscope. A novel metasurface-based nanoantennas array fabricated using a technique of heavy ion tracking is introduced in this paper. The technique has advantages of large area patterning, high aspect ratio of the single pillar, controllable length, and multi-choice of materials etc. Fabrication process, numerical calculation and optical near-field characterization of the structure are presented. Performing as a biochemistry sensor, sensitivity of 137 nm/RIU is obtained for sensing alcohol on the basis of spectroscopy results. Our theoretical and experimental results demonstrate that this structure is capbale of acting as biochemistry sensors for immunoassay and cell/molecular spectrocopy.
A plasmonic lens constructed with elliptical pinholes ranging from micron to nanoscales distribut... more A plasmonic lens constructed with elliptical pinholes ranging from micron to nanoscales distributed in variant periods along the radial direction was presented. Our computational numerical calculation results demonstrated that an ultra-enhanced lasing effect exists while linear polarized plane wave illuminates and passes through the pinholes. The lasing effect can extend the longitudinal focal region and reach as long as 12 µm along the propagation direction. Benefiting from the lasing effect, depth of focus with extraordinarily elongated length (three orders of magnitude in comparison to that of the conventional microlenses) is generated accordingly. Undoubtedly, it may be helpful for practical applications such as data storage, photolithography, and bioimaging.
Journal of Computational and Theoretical Nanoscience, 2019
Inspired by imaging principle of near-field scanning optical microscope (NSOM), meta-pillars arra... more Inspired by imaging principle of near-field scanning optical microscope (NSOM), meta-pillars array is designed and analyzed on the basis of microscopic imaging application with high resolution. Finely focused spots acting as tiny secondary sources for illumination at near-field can be derived under supporting of the meta-pillars for the purpose of increasing imaging resolution. Numerical calculation is carried out on the basis of finite difference and time domain (FDTD) algorithm. Our calculation results demonstrate that the meta-pillars are capable of supporting the microscopic imaging at sub-wavelength resolution.
The anomalous beaming effect of the periodic metallic corrugations functioning as a special case ... more The anomalous beaming effect of the periodic metallic corrugations functioning as a special case of k SP=2π/Λ is discussed and verified by means of both theoretical calculation and experimental probing. A metalens is designed on the basis of the special case. Unlike the conventional beaming of convergence or divergence, the metalens can realize beam collimating, which is useful for practical applications. As a typical application example of the metalens, we integrate the metalens together with a vertical cavity surface emission laser (VCSEL) on the top surface of the aperture area. Our experimental results demonstrate that the integrated metalens is capable of suppressing the divergence angle of the VCSEL for collimation use.
A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array ... more A localized surface plasmon resonance (LSPR) nanosensor by using a rhombic Ag nanoparticle array is proposed and developed. The LSPR extinction spectra of the antigen or antibody with lower concentration are detected. The obtained results detected from 100 nM target molecule indicate a larger wavelength shift for the rhombic based nanosensor than the triangular based nanosensor. By experimental detection, we demonstrated that the refractive index sensitivity is 266.2 nm per refractive index unit for Ag rhombic nanoparticle with in-plane width of ∼140 nm and out-of-plane height of 47 nm.
2011 Second International Conference on Mechanic Automation and Control Engineering, 2011
ABSTRACT The ignition of magnesium alloy chips is a problem during high speed dry machining in in... more ABSTRACT The ignition of magnesium alloy chips is a problem during high speed dry machining in industry. It should be avoided in the practical production. Many factors including machining environment, material composition, tool geometry, cutting parameters etc. can influence the cutting processes. Among these factors, cutting parameters is one of most important elements to induce the ignition of magnesium alloys. AM50A is a commercial magnesium alloy which is widely used in industry. However, very few reports about the ignition conditions of AM50A magnesium alloy are available. In this paper, we investigated the ignition conditions of AM50A magnesium alloy at different cutting parameters. The relationship between ignition conditions and chip morphologies was further explored. The macro morphologies of the chips were observed by optical microscope and the micro structure were obtained by scanning electron microscope (SEM). It is found that the macro morphologies of chips can be characterized into powdered chip, tubular helical chip, acicular helical chip, and long belt chip, which correspond to the different ignition conditions. The powdered chips and acicular spiral chips are easily ignited. They have thinner lamellar thickness compared to the other two types of chips. These results may be used to analyze cutting process and prevent the chip ignition in dry machining magnesium alloy.
Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optica... more Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optical properties on account of their surface plasmon resonance (SPR). In this paper, we mainly discussed the theory background of the enhanced optical properties of noble metal nanoparticles. Mie theory, transfer matrix method, discrete dipole approximation (DDA) method, and finite-difference time domain (FDTD) method applied brute-force computational methods for different nanoparticles optical properties. Some important nanostructure fabrication technologies such as nanosphere lithography (NSL) and focused ion beam (FIB) are also introduced in this paper. Moreover, these fabricated nanostructures are used in the plasmonic sensing fields. The binding signal between the antibody and antigen, amyloid-derived diffusible ligands (ADDLs)-potential Alzheimer's disease (AD) biomarkers, and staphylococcal enterotixn B (SEB) in nano-Moore per liter (nM) concentration level are detected by our des...
A biochemistry nanosensor based on hybrid metallic nanostructure array was put forward in this pa... more A biochemistry nanosensor based on hybrid metallic nanostructure array was put forward in this paper. The hybrid metallic nanostructure array consists of two types Ag nanostuctures, spherical and pyramidal structures with the same period. A biochemistry sensor experiment is demonstrated by detecting the transmittance spectra of hybrid metallic nanostructure using Sciencetech spectrophotometer. The wave peaks of transmittance spectra have shifts when the metallic periods and the refractive index of Ag nanostuctures are different.
A Cr adhesion layer inserted between Ag nanoparticles and a glass substrate, for the purpose of i... more A Cr adhesion layer inserted between Ag nanoparticles and a glass substrate, for the purpose of improving the adhesion of Ag nanoparticles to glass, was observed to cause an abnormal peak shift of extinction spectra in nonspecific reactions. The undesired peak shift misleads molecule detection in non-specific reactions. To solve this issue, a practical technique using n-propyl-trimethoxysilane-based passivation for the detection of amyloid-derived diffusible ligands was investigated as a route to eliminate the abnormal peak shifting observed in the non-specific reactions. To evaluate this passivation technique, localized surface plasmon resonance immunoassay experiments were conducted. Experimental results derived with and without the passivation process were investigated as a basis for comparative analysis. Our experimental results demonstrate that this passivation technique effectively eliminates the observed peak shift originating from the Cr adhesion layer.
ABSTRACT The shape of nanostructure array is one of the important parameters for the nanobiosenso... more ABSTRACT The shape of nanostructure array is one of the important parameters for the nanobiosensor applications. In this paper, we focus on the optical properties of silver pentagram nanostructure arrays based on localized surface plasmon resonance (LSPR). This novel nanostructure array has more hot spots than the tradition nanostructure array. Finite-difference and time-domain (FDTD) method was used to design the suitable structure parameters and the localized electric field distribution on the surface of the nanostructures is also explored too. According to the design results, we fabricated the regularly silver pentagram nanostructure array distributed on the surface of the glass substrate using focused ion beam (FIB) nanofabrication method. The calculated and experiment results show that the pentagram nanostructure array can be realized easily by FIB method. The nanostructure array has potential application for the high sensitivity nanobiosensor in the future. KeywordsLocalized surface plasmon resonance–Finite-difference and time-domain–Pentagram nanostructures–Sensitivity
The sensitivity is the most important parameter in the sensing field. Effort was made to study th... more The sensitivity is the most important parameter in the sensing field. Effort was made to study the effect of gold coating on the sensitivity of rhombic silver nanostructure array through numerical simulation using the discrete dipole approximation method. This study shows that thickness of the gold coating can be varied to tune the sensitivity of the rhombic silver nanostructure array. The Au-Ag nanostructure array is found to possess the maximum refractive index sensitivity of 714 nm/RIU when thickness of gold is 20 nm, thickness of silver is 25 nm, and refractive index of the medium is around 1.35. The condition for achieving the maximum refractive index sensitivity can be used for detecting many species of biomolecules and drugs in the future.
A biochemistry nanosensor was put forward on the basis of a new structure: hybrid metallic nanost... more A biochemistry nanosensor was put forward on the basis of a new structure: hybrid metallic nanostructure array (spherical and pyramidal-shaped nanoparticles) in this paper. The hybrid metallic nanostructure array consists of two types of Ag nanostructures: spherical and pyramidal structures patterned with the same period. Design, fabrication and characterization of the Ag nanostructures were presented. Relevant experimental results were obtained by means of detecting the transmittance spectra of the hybrid metallic nanostructure. Apparent shifting of peak wavelength of the transmittance spectra occurs while varies the periods and the effective refractive index of surrounding mediums. Moreover, there are some sharp and narrow peaks of the transmittance spectra by which it can improve the resolving power of the biochemistry nanosensor.
Journal of Computational and Theoretical Nanoscience, 2010
ABSTRACT The sensitivity is one of the most important parameters in the sensing field. Silver tri... more ABSTRACT The sensitivity is one of the most important parameters in the sensing field. Silver triangular nanostructure array is the traditional substrate for detecting the targets. In this paper, we proposed triangular hybrid Au–Ag nanostructure array to be optimized substrate for nanobiosensor. Effort was made to study sensitivity of triangular hybrid Au–Ag nanostructure array through finite-difference time-domain (FDTD) algorithm-based computational numerical calculation method. The extinction efficiency was obtained by theoretical numerical calculation. It is found that the triangular hybrid Au–Ag nanostructure array possess the refractive index sensitivity of 273 nm/RIU when thickness of silver is 40 nm and the gold is 10 nm, and refractive index of the medium is around 1.33. It is higher than the pure silver nanostructure array (242 nm/RIU).
Journal of Computational and Theoretical Nanoscience, 2009
Optimization of metallic nanoparticles was presented in this paper by aid of computational numeri... more Optimization of metallic nanoparticles was presented in this paper by aid of computational numerical calculation. The optical extinction spectra of rhombic hybrid Au-Ag nanoparticles have been calculated by the discrete dipole approximation (DDA) aided design method. Both material and the thickness of the particles can be used to effectively tune localized surface plasmon resonance. On the basis of the calculated extinction spectra, the crucial parameters of the nanostructure arrays such as thickness can be determined. Using this DDA aided approach, a hybrid Au-Ag nanoparticles array is put forth and designed with the optimized parameter of thickness of metal thin films (h Au = 5 nm, and h Ag = 25 nm). This study shows that the material of the particles have significant effect on the optical properties. The DDA aided design method can provide the optimized structure parameters for the hybrid nanostructures.
ABSTRACT We presented a novel optical non-contact measurement system for detection of the thickne... more ABSTRACT We presented a novel optical non-contact measurement system for detection of the thickness and 3D profile of a hybrid film. The optical interference system and the corresponding compiled data processing program for realizing the non-contact detection of thickness and 3D profile of the hybrid metal film were designed. White light source was used to generate the optical interference of the hybrid Au–Ag metallic film. The characteristics of the film were analyzed through the interference fringe. The original color fringe is obtained from a CCD camera, and the Red-Green-Blue (RGB) raw fringe image is put into our compiled numerical program. The fringe phase was wrapped using Fourier transform technique. The unwrapped phase was reconstructed to be the whole-filed Z image and 3D profile by use of a bilateral filter.
In nanofabrication point of view, fabricating a pattern structured with high-aspect ratio nanoa... more In nanofabrication point of view, fabricating a pattern structured with high-aspect ratio nanoantennas and distribution in large area is quite chanllenge. Especially for the structures being used as biochemistry sensors, the sharp nanoantennas with high-aspect ratio is one of an important features. It can form numerous tiny hot spots as small as 50 nm for directional radiation and beaming which is evidenced by our probing results from near-field scanning optical microscope. A novel metasurface-based nanoantennas array fabricated using a technique of heavy ion tracking is introduced in this paper. The technique has advantages of large area patterning, high aspect ratio of the single pillar, controllable length, and multi-choice of materials etc. Fabrication process, numerical calculation and optical near-field characterization of the structure are presented. Performing as a biochemistry sensor, sensitivity of 137 nm/RIU is obtained for sensing alcohol on the basis of spectroscopy results. Our theoretical and experimental results demonstrate that this structure is capbale of acting as biochemistry sensors for immunoassay and cell/molecular spectrocopy.
A plasmonic lens constructed with elliptical pinholes ranging from micron to nanoscales distribut... more A plasmonic lens constructed with elliptical pinholes ranging from micron to nanoscales distributed in variant periods along the radial direction was presented. Our computational numerical calculation results demonstrated that an ultra-enhanced lasing effect exists while linear polarized plane wave illuminates and passes through the pinholes. The lasing effect can extend the longitudinal focal region and reach as long as 12 µm along the propagation direction. Benefiting from the lasing effect, depth of focus with extraordinarily elongated length (three orders of magnitude in comparison to that of the conventional microlenses) is generated accordingly. Undoubtedly, it may be helpful for practical applications such as data storage, photolithography, and bioimaging.
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Papers by Shaoli Zhu