- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A nanosensor with ultra-high FOM based on tunable malleable multiple Fano resonances in a waveguide coupled isosceles triangular resonator
摘要： A simple plasmonic structure, which is made up of a metal baffle in the middle of the metal–insulator–metal (MIM) waveguide coupled with an isosceles triangular cavity, is reported to achieve triple Fano resonances. These Fano resonances are numerically calculated by the finite element method (FEM). Besides, the multimode interference coupled mode theory (MICMT) and the standing wave theory are used for analyzing the Fano resonances phenomenon. On the one hand, these three Fano resonances can be independently tuned by adjusting the structural parameters, which makes the design of highly integrated photonic circuits more flexible. On the other hand, the proposed structure is well malleable and can be easily extended to a quintuple Fano system by introducing a ring resonator. Furthermore, the suggested structure can act as a high efficient refractive index (RI) sensor, yielding a great sensitivity of 1200 nm/RIU and a ultra-high maximal figure of merit (FOM) value of 3.0 × 106. Comparing with other similar sensors, our structure has relatively good sensitivity and it is superior to other structures in the maximal FOM, which obviously demonstrates its excellent nano-sensing performance.
关键词： Multiple Fano resonances,Multimode interference coupled mode theory (MICMT),Refractive index (RI) sensor,Ultra-high FOM,Surface plasmon polaritons (SPPs)
更新于2025-09-23 15:21:01
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Optical characteristics of the undamaged and laser damaged K9 glass in terahertz band
摘要： K9 glass is an important optical element of the high energy laser system. In an attempt to investigate the variation of optical properties of K9 glass before and after laser induced damage, based on the transmission terahertz time-domain spectral system, the undamaged and the damaged K9 glasses induced by laser were tested to obtain the terahertz time-domain and frequency-domain spectra and the refractive index and absorption coef?cient of the samples were calculated in terahertz band for further analysis. Results show that with the increase of laser energy, from the undamaged to the damaged K9 glasses to different extent, the peak to peak value in time domain and the amplitude value in frequency domain present a decreasing trend in varying degrees, and in the 0.4～0.5 THz band, the absorption coef?cient increases continuously with a slight change of refractive index, which indicates that K9 glass not only appears the melting and fracture in the macroscopic morphology after laser-induced damage, but also forms non-bridged oxygen atoms in its microstructure with more ion bonds and free electrons and the change of ion polarization. In this regard, this paper provides a technical basis for exploring the micro characteristics of K9 glass after laser-induced damage, and lays a good foundation for the application of terahertz time-domain spectroscopy to laser-induced damage analysis.
关键词： terahertz time-domain spectrum,K9 glass,laser-induced damage,refractive index,absorption coef?cient
更新于2025-09-23 15:21:01
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High sensitivity surface plasmon resonance sensor based on D-shaped photonic crystal fiber with circular layout
摘要： A high sensitivity D-shaped photonic crystal fiber sensor based on surface plasmon resonance is proposed for refractive index sensing. By using finite element method, the sensing properties of the proposed sensor are investigated. The numerical results show a very high average sensitivity of 14600 nm/RIU with the high resolution of 6.80 × 10?6 RIU for refractive index (RI) of analytes ranging from 1.420 to 1.435. The layout of the air holes is designed to be circular and only two layers in this D-shaped photonic crystal fiber. The metallic gold is used as the surface plasmon resonance activity material, which is deposited on the polishing surface. The analyte is placed on the outer layer of the D-shaped photonic crystal fiber. This D-shaped photonic crystal fiber solves the difficulty of gold-plated film and fill analyte in the holes. The proposed PCF structure is a combination of circular layout and D-shaped, which also leads to the proposed sensor easy to fabricate and has considerable sensitivity.
关键词： Sensitivity,Photonic crystal fiber,Refractive index sensor,Surface plasmon resonance
更新于2025-09-23 15:21:01
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Three-core photonic crystal fiber surface plasmon resonance sensor
摘要： A three-core photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor with high performance is presented. The structure of the biosensor is easy to implement and has good repetition. The outer layer of the fiber structure is gold film. The analyte is placed on the surface of the gold film. The Full vector finite element method is used to numerical simulation and analysis the transmission mode and characteristics of the three-core PCF-SPR biosensor. The influence of sensor structure parameters on sensing performance is investigated. The structure parameters are optimized. The optimum structure parameters are given. The refractive index (RI) sensitivity of the sensor is discussed there. The results show that the average refractive index sensitivity of the sensor is 3435 nm/RIU in the sensing range of 1.33–1.40, and the resolution is 2.91 × 10?6 RIU. The sensor has the advantages of high sensitivity and high resolution. And it can be applied to real-time detection of the bio-molecules and small drug-molecules.
关键词： Photonic crystal fiber,Biosensor,Surface plasmon resonance,Refractive index sensitivity,Finite element method
更新于2025-09-23 15:21:01
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Active Maintenance of the Gradient of Refractive Index Is Required to Sustain the Optical Properties of the Lens
摘要： To determine whether the cellular physiology of the lens actively maintains the optical properties of the lens and whether inhibition of lens transport affects overall visual quality. One lens from a pair of bovine lenses was cultured in artificial aqueous humor (AAH), while the other was cultured in either AAH-High-K+ or AAH + 0.1 mM ouabain for 4 hours. Lens pairs or whole enucleated eyes were then imaged in 4.7 Tesla (T) high-field small animal magnet. Lens surface curvatures, T1 measurements of water content, and T2 measurements of water/protein ratios were extracted from cultured lenses, while the geometrical parameters that define the optical pathway were obtained from whole eyes. Gradients of refractive index (GRIN), calculated from T2 measurements, and the extracted geometric parameters were inputted into optical models of the isolated lens and the whole bovine eye. Inhibiting circulating fluxes by inhibiting the Na/K-ATPase with ouabain or depolarization of the lens potential by High K+ caused changes to lens water content, the water/protein ratio (GRIN) and surface geometry that manifested as an increase in optical power and a decrease in negative spherical aberration in cultured lenses. Changes to optical properties of the lens resulted in a myopic shift that impaired vision quality in the optical model of the bovine eye. The cellular physiology of the lens actively maintains its optical properties and inhibiting the Na/K/ATPase induces a myopic shift in vision similar to that observed clinically in patients who go on to develop cataract.
关键词： physiological optics,optical modeling,cataract,gradient of refractive index,lens physiology,magnetic resonance imaging
更新于2025-09-23 15:21:01
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Langkawi, Malaysia (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Modal Properties of a Varied High Indexed Large Core 4-Mode Photonic Crystal Fiber
摘要： A varied high indexed, large core 4-mode photonic crystal fiber is proposed. Consequences of variation in the refractive index of the materials used in the rings have been analyzed through the far field distribution and phase of each mode. The influence of different, air hole diameters and distances between the holes of the fiber is studied.
关键词： refractive index,germanium doped fiber,photonic crystal fiber,design
更新于2025-09-23 15:21:01
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Lattice effect in Mie-resonant dielectric nanoparticle array under oblique light incidence
摘要： Ultra-thin optical structures, known as metasurfaces, have shown promising light controlling capability at the nanoscale. In this paper, we study their particular case, a periodic array of high-refractive-index nanoparticles with electric and magnetic resonances. The main result of the work is a numerical demonstration that the lattice effect in the periodic arrangement of nanoparticles changes the resonance position even if the resonances are above the diffraction wavelength (Rayleigh anomaly). We show that the disk resonance changes can be achieved not only by varying periods of the array under normal light incidence but also by changing the incident angle.
关键词： metasurfaces,Rayleigh anomaly,electric and magnetic resonances,high-refractive-index nanoparticles,lattice effect
更新于2025-09-23 15:21:01
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Direct Observation of Core-Shell Structures in Individual Lead Titanate Ferroelectric Nanostructures by Tip-Enhanced Refractive Index Mapping
摘要： Ferroelectrics undergo a size-driven phase transition at the nanoscale below which the spontaneous polarization, their defining property, irrevocably ceases. This threshold often referred to as the superparaelectric limit has tremendous technological relevance in an era of progressing integration. Just as the balance of short-range elastic and long-range electrostatic ordering in bulk, the critical size depends on temperature. Room-temperature tip-enhanced Raman spectroscopy (TERS) imaging of individual lead titanate (PbTiO3) nanoislands is reported with a spatial resolution of ≈3 nm. Monitoring the spectral shift of the gold-tip enhanced luminescence, which depends on the local refractive index, images grains composing the nanoislands. The wavelength of the enhanced luminescence shifts between the grains and their boundaries indicating the predicted core–shell structure of ferroelectric and paraelectric phase. The shear force configuration rules out the distance dependence of capacitive plasmonic coupling between tip and substrate as the origin of the observed shift. As the reported temperature-changes in nonresonant TERS do not account for noticeable thermal effects, the underlying, even though weak, tip-enhanced Raman spectrum of the grain core reflects PbTiO3 close to the ferroelectric-to-paraelectric phase transition which is primarily related to the finite size of the grains.
关键词： ferroelectric,tip-enhanced Raman spectroscopy,core–shell structure,local refractive index imaging,lead titanate
更新于2025-09-23 15:21:01
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Zukunftsperspektiven des Femtosekundenlasers in der Vorderabschnittschirurgie; Future perspectives of the femtosecond laser in anterior segment surgery;
摘要： Around 12 years after its introduction laser cataract surgery (LCS) has enabled remarkable progress, such as extremely precise capsulotomy and lens fragmentation with reduced or no ultrasound energy at all (zero phako); however, another innovation push is necessary to bring this technology to its full potential. Among the many benefits that have not yet been fully explored are primary posterior laser capsulotomy (PPLC) and the use of the femtosecond laser in pediatric cataract patients. In the present collective of patients in whom a PPLC was carried out at the end of the operation, a clearly reduced prevalence of secondary cataract could be observed, whereas the short additional intervention was not associated with notable complications. The LCS in infants is best carried out as an off-label procedure, which has been rendered more precise by the Bochum formula. In the near future, postoperative laser fine tuning will enable the target refraction to be achieved in most patients. Laser-induced refractive index change (LIRIC) will enable very exact refraction alterations on an already implanted intraocular lens (IOL), on a contact lens and on a treatment native cornea. A new version of the Scheimpflug camera will be used just prior to surgery to analyze the morphology and kernel density of the lens opacity and to carry out a real-time grading of lens hardness. Based on this categorization, where the system classifies the results into five different density grades, the surgeon is automatically provided with an individualized fragmentation pattern defined preoperatively by the operator. A further innovation of the same system involves microcorneal incisions for fine tuning of residual refractive deficits.
关键词： Femtosecond laser-assisted cataract surgery,Bochum formula,Postoperative refractive enhancement/fine tuning,Primary posterior laser capsulotomy,Laser-induced refractive index change
更新于2025-09-23 15:19:57
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Optoplasmonics: basic principles and applications
摘要： Plasmonic and photonic elements often have complementary optical properties, motivating the development of ‘optoplasmonic’ hybrid systems in which the photonic and plasmonic elements can synergistically interact. The overall goal in the design of optoplasmonic structures is to overcome the limitations of the individual building blocks or to generate entirely new properties that reach beyond what is possible with conventional photonic or plasmonic structures. After providing a brief introduction into the relevant optical properties of plasmonic and photonic building blocks, this manuscript reviews optoplasmonic architectures that contain plasmonic nanoantennas embedded in a de?ned photonic environment generated by discrete dielectric nanoparticles (NPs), microcavities, waveguides, or photonic crystals, as well as all-metal NP or metal/dielectric NP hybrid arrays in which diffracted modes interact with the plasmons of metal NPs. The fundamental working principles of these optoplasmonic systems are analyzed and selected applications and fabrication strategies are discussed.
关键词： metamaterials,metasurface,sensing,hybrid materials,high refractive index dielectrics,plasmonics,nanophotonics
更新于2025-09-23 15:19:57