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Plasmonic refractive index sensor with multi-channel Fano resonances based on MIM waveguides
摘要： A multi-channel Fano resonant structure is proposed and analyzed based on subwavelength metal–insulator–metal (MIM) waveguides. First, two MIM output ports associated with specific side-coupled cavities are designed to locate at the center and quarter positions of an end-coupled cavity, respectively. Since the interference between the dark and bright modes, dual-channel Fano resonances with asymmetrical lines shapes are obtained at both ports, respectively. High sensitivity and figure of merits are investigated. Besides, phase shifts are also investigated leading to positive and negative group delays available at the Fano peaks and dips, respectively. Likewise, two extra output ports with identical resonant cavities are placed on the other side of the end-coupled cavity. In this case, four-channel Fano resonances with considerable performances are obtained. The proposed structure is analyzed by the coupled mode theory and the finite difference time domain method. It is believed this device can be used as a chip-scale refractive index sensor and optical filter.
关键词： Fano resonances,subwavelength MIM waveguide,refractive index sensor.
更新于2025-09-23 15:21:01
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Modal characteristics of refractive index engineered hybrid plasmonic waveguide
摘要： In this work, we proposed a novel design of a refractive index engineered subwavelength grating silicon-based hybrid plasmonic waveguide via the finite element method. The intensity integral (Γ) in the upper cladding can be controlled by varying the thickness (HSi) of the top silicon layer. The highest evanescent field ratio of 0.85 is obtained at HSi=200 nm which allows the hybrid mode to confine in the low index medium and a large evanescent field resides in the upper cladding. The sensitivity of the waveguide is calculated by monitoring the change in the effective refractive index to the ambient refractive index. The maximum mode sensitivity of 0.7 is obtained. The spectral performance of the subwavelength grating (SWG) hybrid plasmonic waveguide (HPWG) based ring resonator design is studied which exhibits a sensitivity as high as 1000 nm/RIU which is higher than the previously reported values. We believe that the proposed waveguide scheme is an ideal candidate to produce highly sensitive lab-on-chip sensors.
关键词： microring resonator,refractive index sensor,Subwavelength grating hybrid plasmonic waveguide,Evanescent field ratio
更新于2025-09-23 15:21:01
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Micro-channeled Single Mode Fiber Plasmonic Sensor with ITO-TiO <sub/>2</sub> Bilayer
摘要： A microchannel incorporated single mode fiber plasmonic sensor coated with ITO-TiO2 bilayer is proposed in this paper. The sensor responds over a wide refractive index range from 1.33 to 1.41 and sensitivity of 10500nm/RIU is obtained for refractive index 1.41. oxide which is employed to enhance the evanescent field. By taking the aid of a conventional SMF which offers significant cost reduction and good compatibility, our proposed structure achieves reasonably high sensitivity along with wide sensing range.
关键词： sensitivity,Single mode fiber,refractive index
更新于2025-09-23 15:21:01
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PERFORMANCE IMPROVEMENT OF PATCH ANTENNA USING CIRCULAR SPLIT RING RESONATORS AND THIN WIRES EMPLOYING METAMATERIALS LENS
摘要： In this paper, the left-handed metamaterial which acts as a lens is employed to improve the performance of a microstrip patch antenna. The left-handed metamaterial used in this work is a three-dimensional periodic structure which consists of circular split ring resonators and thin wires. The three-dimensional periodic metamaterial structure shows angular independency characteristics in wide range angles, so it acts as a metamaterial lens. However, the MTM structure in?nite periodicity truncation has no impacts on the MTM lens scattering, e?ective parameters and homogeneity. The left-handed metamaterial is placed in front of the microstrip patch antenna and due to the negative refractive index property of the left-handed metamaterial; the radiated electromagnetic beam size decreases which results in a highly focused beam. The proposed antenna has been designed and simulated using CST microwave studio, and the metamaterial e?ective parameters are extracted from the S parameters by using Nicolson-Ross-Weir algorithm and by selecting the appropriate ambiguity branch parameter. Furthermore, the angular independency of the metamaterial lens has been veri?ed by rotating the metamaterial structure with respect to the excitation probe of the transverse electromagnetic waves and extracting the S-parameters and the e?ective parameters for each rotation angle. A parametric analysis has been performed to study the e?ects of the patch antenna and left-handed metamaterial lens separation and the size of the three-dimensional left-handed metamaterial structure on the radiating properties and the impedance matching of the proposed antenna. For the experimental veri?cation, the proposed antenna operating at 10 GHz is fabricated; the return loss, radiation pattern and gain for the proposed antenna with and without metamaterial are measured. Furthermore, the results show that the antenna gain is improved by 4.6 dB which validates the concept of beam focusing using negative refractive index metamaterial structure, while the return loss and bandwidth are slightly reduced. The simulation and experiment investigated the idea of the beam focusing using negative refractive index metamaterial lens in microwave regime.
关键词： microstrip patch antenna,CST microwave studio,beam focusing,Nicolson-Ross-Weir algorithm,parametric analysis,left-handed metamaterial,circular split ring resonators,negative refractive index,angular independency,experimental verification,thin wires
更新于2025-09-23 15:21:01
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Tunable thermo-piezo-plasmonic effect on core/shell nanoparticles under laser irradiation and external electric field
摘要： This work is focused on the characterization of the opto-heating generation in thermo-piezo-plasmonic solutions of gold-PbZrTiO3 (PZT) core/shell nanoparticles. Core/shell nanoparticles have been prepared by the laser ablation in liquid method. Linear and nonlinear optical properties of proposed nanoparticles were studied by optical spectroscopy and the Z-scan technique under external voltage to investigate the piezo-photonic effect. Furthermore, the linear optical properties of these nanostructures were calculated vie dipole approximation method with different core size and different shell thickness of samples immersed in water and poly-vinyl-pyrrolidone. In addition, thermo-plasmonic effects of samples are investigated theoretically and experimentally by the finite element method of COMSOL multiphysics V5.4 and infrared camera under laser irradiation and external electric field. The results revealed a clear tunable and adjustable linear and nonlinear behavior and thermo-piezo-plasmonic properties under external effects. The temperature elevation is ranging of ?T = 3.7–14.1 °C under different external effects. Accordingly, these results encourage to uses proposed samples for the cancer treatment and the different biomedical applications.
关键词： Nonlinear refractive index,External electric field,Core/shell NPs,Laser irradiation,Thermoplasmonic,Piezoelectric,Z-scan technique,Schottky barrier
更新于2025-09-23 15:21:01
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Luminescence of Phosphate Glasses: P2O5-ZnO-BaF2-K2TeO3-Al2O3-Nb2O5 Doped with Sm3+ Ions for Display and Laser Material
摘要： Luminescent phosphate glasses having the composition 40P2O5-30ZnO-20BaF2-3.8K2TeO3-1.2Al2O3-5Nb2O5 in mol.% doped with 3 9 103 ppm and 4 9 103 ppm Sm2O3 were successfully prepared by a melt-quenching technique. The investigated glasses were characterized by x-ray diffraction, UV–visible–NIR, absorption, emission, and ?uorescence lifetime analysis. The radiative properties were calculated using Judd–Ofelt (J–O) spectral intensity parameters for each of the glasses, which revealed the following trend: X2 > X4 > X6. The J–O intensity parameters were used to evaluate the spontaneous emission properties including branching ratios, transition probabilities, and radiative lifetime. The value of the optical energy band gap was found to decrease with an increase in Sm3+ content, which is explained on the basis of structural changes. The calculated stimulated emission cross-section studied was high, and increased from rSE; at 1.62 lm of glasses 3.81 9 10(cid:2)21 cm2 to 4.38 9 10(cid:2)21 cm2 with increasing Sm3+ ion concentration. The structure of the glasses was investigated by computing Internuclear (cid:3) and ?eld strength F( ) and measurement of Raman spectra.
关键词： refractive index,UV–Vis–NIR,Judd–Ofelt analysis,emission cross-section,Raman spectra,Oxide glasses,density,optical energy gap
更新于2025-09-23 15:21:01
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Nonlinear Optics || The Intensity-Dependent Refractive Index
摘要： The refractive index of many optical materials depends on the intensity of the light used to measure the refractive index. In this chapter, we examine some of the mathematical descriptions of the nonlinear refractive index and examine some of the physical processes that give rise to this effect. In the following chapter, we study the origin of optical nonlinearities in molecular systems, in Chapter 6 we study the intensity-dependent refractive index resulting from the resonance response of an atomic system, and in Chapter 7 we study some physical processes that result from the nonlinear refractive index.
关键词： intensity-dependent,atomic system,optical materials,nonlinear refractive index,molecular systems
更新于2025-09-23 15:21:01
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Nonlinear Optics || Processes Resulting from the Intensity-Dependent Refractive Index
摘要： In this chapter, we explore several processes of practical importance that occur as a result of the intensity-dependent refractive index.
关键词： refractive index,self-trapping,laser beam breakup,self-focusing,nonlinear optics
更新于2025-09-23 15:21:01
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Nonlinear Optics || The Electrooptic and Photorefractive Effects
摘要： The electrooptic effect is the change in refractive index of a material induced by the presence of a static (or low-frequency) electric field. In some materials, the change in refractive index depends linearly on the strength of the applied electric field. This change is known as the linear electrooptic effect or Pockels effect. The linear electrooptic effect can be described in terms of a nonlinear polarization given by Pi(ω) = 2ε0 Σj k χ(2)ij k (ω = ω + 0)Ej (ω)Ek(0). Since the linear electrooptic effect can be described by a second-order nonlinear susceptibility, it follows from the general discussion of Section 1.5 that a linear electrooptic effect can occur only for materials that are noncentrosymmetric. Although the linear electrooptic effect can be described in terms of a second-order nonlinear susceptibility, a very different mathematical formalism has historically been used to describe the electrooptic effect; this formalism is described in Section 11.2 of this chapter. In centrosymmetric materials (such as liquids and glasses), the lowest-order change in the refractive index depends quadratically on the strength of the applied static (or low-frequency) field. This effect is known as the Kerr electrooptic effect or as the quadratic electrooptic effect. It can be described in terms of a nonlinear polarization given by Pi(ω) = 3ε0 Σj kl χ(3)ij kl(ω = ω + 0 + 0)Ej (ω)Ek(0)El(0).
关键词： refractive index,electrooptic effect,Kerr electrooptic effect,Pockels effect,nonlinear polarization
更新于2025-09-23 15:21:01
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Phenomena of Optical Metamaterials || Active Optical Metamaterials
摘要： At the turn of the century, a new field of research emerged at the crossing between physics, electrical engineering, and materials science. The study of metamaterials addresses the rational design and arrangement of a material’s building blocks to attain physical properties that may go significantly beyond those of its original constituent materials. Most often, the concept of metamaterials is associated with electromagnetic wave propagation, where the engineering of resonant subwavelength structures allows for the precise control of effective wave properties. It is this advanced functionality that enables the realization of unique wave phenomena, such as the focusing of light below the diffraction limit or electromagnetic cloaking of objects—concepts that have captured the imagination of researchers and the general public alike. Importantly, the element of functionality is an integral part of the metamaterial concept.
关键词： nanoplasmonics,plasmonics,negative refractive index,optical gain,metamaterials
更新于2025-09-23 15:21:01