- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Role of the La/K Compositional Ratio in the Properties of Waveguides Written by Fs-Laser Induced Element Redistribution in Phosphate-Based Glasses
摘要： The local modification of the composition of glasses by high repetition femtosecond laser irradiation is an attractive method for producing photonic devices. Recently, the successful production of waveguides with a refractive index contrast (?n) above 10?2 by fs-laser writing has been demonstrated in phosphate glasses containing La2O3 and K2O modifiers. This large index contrast has been related to a local enrichment in lanthanum in the light guiding region accompanied by a depletion in potassium. In this work, we have studied the influence of the initial glass composition on the performance of waveguides that are produced by fs-laser induced element redistribution (FLIER) in phosphate-based samples with different La and K concentrations. We have analyzed the contribution to the electronic polarizability of the different glass constituents based on refractive index measurements of the untreated samples, and used it to estimate the expected index contrast caused by the experimentally measured local compositional changes in laser written guiding structures. These estimated values have been compared to experimental ones that are derived from near field images of the guided modes with an excellent agreement. Therefore, we have developed a method to estimate before-hand the expected index contrast in fs-laser written waveguides via FLIER for a given glass composition. The obtained results stress the importance of considering the contribution to the polarizability of all the moving species when computing the expected refractive index changes that are caused by FLIER processes.
关键词： photonic devices,waveguides,element redistribution,ion migration,fs-laser writing,refractive index contrast,glass
更新于2025-09-23 15:19:57
-
High-performance plasmonic refractive index sensors via synergy between annealed nanoparticles and thin films
摘要： Plasmonic nanostructure-based refractive index (RI) sensors are the core component of biosensor systems and play an increasingly important role in the diagnosis of human disease. However, the costs of traditional plasmonic RI sensors are not acceptable to everyone due to their expensive fabrication process. Here, a novel low-cost and high-performance visible-light RI sensor with a particle-on-film configuration was experimentally demonstrated. The sensor was fabricated by transferring annealed Au nanoparticles (NPs) onto a thin gold film with polymethyl methacrylate (PMMA) as a support. RI sensitivities of approximately 209 nm/RIU and 369 nm/RIU were achieved by reflection and transmission spectrum measurements, respectively. The high sensitivity is due to the strong plasmon-mediated energy confinement within the interface between the particles and the film. The possibility of wafer-scale production and high working stability achieved by the transfer process, together with the high sensitivity to the environmental RI, provides an extensive impact on the realization of universal biosensors for biological applications.
关键词： high stability,transfer process,low cost,refractive index sensors,particle-on-film structure
更新于2025-09-23 15:19:57
-
Analysis of a Single Solid Core Flat Fiber Plasmonic Refractive Index Sensor
摘要： In this article, a single solid core flat fiber (SSCFF) refractive index sensor based on surface plasmon resonance (SPR) is proposed and analyzed numerically using the finite element method (FEM). The proposed flat fiber consists of a single array of five circular holes. Among them the central hole is made of GeO2-doped silica which is forming the core. Other holes are filled with air and situated symmetrically on both sides of the central solid core. The upper flat surface of the fiber is coated with a thin plasmonic gold layer which is protected by an active titanium dioxide layers. Analyte is situated on top of these layers. The wavelength interrogation technique is applied to study the coupling characteristics between the core-guided mode and the surface plasmon mode as well as for the refractive index measurement. Numerical analysis results show that this sensor is able to detect high refractive index analytes from 1.49 to 1.54 with a good linear response. Additionally, the dependence of surface plasmonic resonance wavelength on analyte refractive index is studied. The maximum wavelength sensitivity of this sensor is found to be 4782 nm/RIU with a high resolution of 2.09 × 10?5 RIU. The effects of different structural parameters on loss spectrum are studied in detail to optimize this SSCFF structure. In comparison to traditional PCF, this SSCFF structure is fabrication complexity free as well as a suitable candidate for developing portable devices and high refractive index analyte sensors, particularly chemical and protein sensors.
关键词： Photonic crystal fiber,Surface plasmon,Optical sensing,Finite element method,Refractive index sensor
更新于2025-09-23 15:19:57
-
Highly Efficient Tandem White OLED Using a Hollow Structure
摘要： A simple fabrication method for a light extraction layer is required. In this report, an internal light extraction layer composed of a high refractive index material and an air void is fabricated in five steps. A direct printing process followed by annealing of the randomly arrayed poly(benzyl methacrylate) pillars after a planarization process using TiO2-nanoparticle dispersed resist and sol is used. These substrates are used for light extraction in white tandem organic light emitting diodes (WOLEDs). By combining the hollow structure and hemi-spherical lens, WOLEDs without and with the light extraction structures are found to show maximum external quantum efficiencies of 35.6% and 103%, respectively. The power efficiencies at 100 cd m?2 of the WOLEDs without and with the light extraction structures are found to be 26.5 and 93.2 lm W?1, respectively. A color rendering index of 86.4, correlated color temperature of 4860 K, and CIE of (0.353, 0.389) are achieved in the WOLEDs with light extraction structures.
关键词： organic light emitting diodes,high refractive index,light extraction efficiency,nanoimprint lithography,light scattering layers
更新于2025-09-23 15:19:57
-
Impact of refractive index increment on the determination of molecular weight of hyaluronic acid by muti-angle laser light-scattering technique
摘要： Hyaluronic acid (HA) is applied in a number of medical applications and HA of different molecular weight (Mw) are used in different pharmaceutical preparations. In determination of Mw by muti-angle laser light-scattering (MALS), refractive index increment (dn/dc) is an important parameter for accuracy. Herein, the influence of dn/dc on the Mw of HA in stroke-physiological saline solution is investigated by MALS in this work. Additionally, the Mw variation of HA in the manufacturing process of preparations is measured. It is shown that each HA sample corresponds to a specific value of dn/dc, which is varied from 1.38 to 1.74 L/g with the Mw increasing from 13.5 to 2840 kDa in solution. It is indicated by the results from both MALS approach and viscometry that appropriate dn/dc should be selected for Mw determination. In steam sterilization process of preparations at 121 °C, the Mw and conformation of HA can be accurately and rapidly determined by MALS. This work provides a precise method to determine the Mw of HA in the medical applications and preparation industries.
关键词： Molecular weight,Viscometry,Muti-angle laser light-scattering,Steam sterilization,Hyaluronic acid,Refractive index increment
更新于2025-09-23 15:19:57
-
Nanoparticle Design Rules for Colorimetric Plasmonic Sensors
摘要： Localized surface plasmon resonance (LSPR) sensors are used in a broad range of detection applications across the chemical, biological, environmental, and medical disciplines. These types of sensors traditionally use the plasmon resonance wavelength of a nanoparticle array to detect changes in refractive index at the sensor surface and therefore require expensive spectroscopic instrumentation for readout. However, simple, portable, and low-cost LSPR sensors can be achieved by transitioning to colorimetric measurements, in which refractive index changes are quantified using the R, G, and B pixel intensities from digital nanoparticle images. In this study we use R, G, and B pixel intensities to quantify color coordinates in the HSV, CIE L*a*b, and rgb chromaticity color spaces. We show that for sensors comprising 115-nm diameter nanoparticles, hue (H) is the most sensitive color parameter, with a change per refractive index unit (Dhue/DRIU) of 0.71 and a figure of merit of 183 RIU-1. Furthermore, we compared hue figures of merit (FOM) for nanoparticles in four different diameters (34.1, 59.8, 81.5, and 115 nm) and showed that hue sensitivity peaks at a diameter of 81.5 nm, with a FOM of 222 RIU-1. In contrast, the spectroscopic sensitivity, quantified in units of Dnm/DRIU, increased continually with nanoparticle size. Therefore, the design requirements for colorimetric plasmonic sensors differ from those for spectroscopic plasmonic sensors. This difference in size dependence was explored further using Mie calculations to simulate nanoparticle extinction spectra. Our results revealed that while lmax responds linearly to refractive index changes, hue responds in a sigmoidal fashion. As a result, the nanoparticle size used in colorimetric sensors relying on hue measurement should be carefully selected to achieve a linear sensor response. We provide general design rules for optimizing hue-based colorimetric sensors and demonstrate that our sensor can be used with a smartphone to detect antibody-antigen interactions.
关键词： portable,refractive index,nanosensor,hue,smartphone,image processing
更新于2025-09-23 15:19:57
-
Structural Colors Enabled by Lattice Resonance on Silicon Nitride Metasurfaces
摘要： Artificial color pixels based on dielectric Mie resonators are appealing for scientific research as well as practical design. Vivid colors are imperative for displays and imaging. Dielectric metasurface-based artificial pixels are promising candidates for developing flat, flexible, and/or wearable displays. Considering the application feasibility of artificial color pixels, wide color gamuts are crucial for contemporary display technology. To achieve a wide color gamut, ensuring the purity and efficiency of nanostructure resonance peaks in the visible spectrum is necessary for structural color design. Low-loss dielectric materials are suitable for achieving vivid colors with structural color pixels. However, high-order Mie resonances prevent color pixels based on dielectric metasurfaces from efficiently generating highly saturated colors. In particular, fundamental Mie resonances (electric/magnetic dipole) for red can result in not only a strong resonance peak at 650 nm, but also high-order Mie resonances at shorter wavelengths, which reduces the saturation of the target color. To address these problems, we fabricated silicon nitride metasurfaces on quartz substrates and applied Rayleigh anomalies at relatively short wavelengths to successfully suppress high-order Mie resonances, thus creating vivid color pixels. We performed numerical design, semianalytic considerations, and experimental proof-of-concept examinations to demonstrate the performance of the silicon nitride metasurfaces. Apart from traditional metasurface designs that involve transmission and reflection modes, we determined that lateral light incidence on silicon nitride metasurfaces can provide vivid colors through long-range dipole interactions; this can thus extend the applications of such surfaces to eyewear displays and guided-wave illumination techniques.
关键词： metasurfaces,Mie resonances,lattice resonances,color,silicon nitride,high-refractive-index nanostructures
更新于2025-09-23 15:19:57
-
Under-Etched Plasmonic Disks on Indium Tin Oxide for Enhanced Refractive Index Sensing on a Combined Electrochemical and Optical Platform
摘要： A simple approach to enhance the refractive index sensitivity of gold nanodisks immobilized on electrically conducting indium tin oxide (ITO) substrates has been demonstrated. A two-fold increase in sensitivity to bulk refractive index change was achieved by substrate under-etching of gold nanodisks on ITO in 50 mM sulfuric acid. The influence of an intermediate titanium adhesion layer was investigated and was found to markedly influence the etching pattern and time. Etching with an adhesion layer resulted in enhanced refractive index sensitivity on disk-on-pin like structures after long etching times, whereas etching of disks deposited directly on ITO resulted in a disk-on-pincushion like configuration and similarly enhanced sensitivity already at shorter times. The gold disks remained electrically connected to the ITO substrate throughout etching and allowed site-specific electrodeposition of poly(3-aminophenol) at the nanodisks, showing enhanced thin-film refractive index sensitivity. This work demonstrates a simple method for enhancing refractive index sensitivity of nanostructures on ITO substrates for combined electrochemical and optical platforms, and subsequently a method to modify the surface of the electrically connected nanostructures, which has potential application in biosensing.
关键词： plasmonics,refractive index sensor,colloidal lithography
更新于2025-09-23 15:19:57
-
A Large Detection-Range Plasmonic Sensor Based on An H-Shaped Photonic Crystal Fiber
摘要： An H‐shaped photonic crystal fiber (PCF)‐based surface plasmon resonance (SPR) sensor is proposed for detecting large refractive index (RI) range which can either be higher or lower than the RI of the fiber material used. The grooves of the H‐shaped PCF as the sensing channels are coated with gold film and then brought into direct contact with the analyte, which not only reduces the complexity of the fabrication but also provides reusable capacity compared with other designs. The sensing performance of the proposed sensor is investigated by using the finite element method. Numerical results show that the sensor can work normally in the large analyte RI (na) range from 1.33 to 1.49, and reach the maximum sensitivity of 25,900 nm/RIU (RI units) at the na range 1.47–1.48. Moreover, the sensor shows good stability in the tolerances of ±10% of the gold‐film thickness.
关键词： fiber optics sensors,photonic crystal fiber,refractive index sensor,surface plasmon resonance
更新于2025-09-23 15:19:57
-
Theoretical assessment of D-shaped optical fiber chemical sensor associated with nanoscale silver strip operating in near-infrared region
摘要： In present work, we propose a surface plasmon resonance based D-shaped fiber for the chemical sensor using nanoscale silver strip deposited over polished surface of single mode fiber. Various parameters of the designed sensors are optimized to achieve the maximum wavelength sensitivity. The sensing properties are investigated using finite element method based on COMSOL Multiphysics. An average wavelength sensitivity of 2100 nm/RIU is obtained for wide range of refractive index (RI) varying between 1.34 and 1.42 and a maximum wavelength and amplitude sensitivity of 3240 nm/RIU and 192 RIU?1 is achieved for RI range varying between 1.38 and 1.42 with 3.08 × 10?5 RIU resolution. The results indicate that our designed sensor perform effectively in high RI range and hence can be used in chemical and biological sensing.
关键词： Nanoscale,Surface plasmon resonance,Refractive index,D-shaped,Evanescent waves
更新于2025-09-23 15:19:57