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过滤筛选
- 2019
- Photovoltaics
- Finite-difference
- Nanotechnology
- Absorption enhancement
- Plasmonics
- Time domain simulation
- Localized surface plasmon resonance
- Optoelectronic Information Materials and Devices
- Islamic Azad University
- Aerospace Research Institute
- Tehran University
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Controllable tuning of Fabrya??Perot cavities <i>via</i> laser printing
摘要： The Fabry–Perot (FP) cavity is one of the basic optical components that has been widely applied in interferometry, spectroscopy, lasers and optoelectronic devices. Currently, tailorable FP cavities are highly desirable for fast and in situ modulation, which is crucial for optoelectronic devices and their integration. Here a simple tuning strategy of FP cavity mode is developed based on the plasmon-assisted laser printing technique. The laser irradiation induces photochemical and/or photothermal degradation of the polymer medium in the cavity, which is highly dependent on the film thickness and laser power. Thus, the FP cavity mode can be precisely and continuously tuned with irradiation time, which is then monitored using reflection spectra. Such a laser printing strategy is facile and general, which is capable of generating different structural colours.
关键词： laser printing,structural colours,plasmon-assisted,photochemical degradation,photothermal degradation,Fabry–Perot cavity
更新于2025-09-23 15:21:01
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Surface Plasmon Resonance-Enhanced Visible-NIR-Driven Photocatalytic and Photothermal Catalytic Performance by Ag/Mesoporous Black TiO2 Nanotubes Heterojunctions
摘要： Ag/mesoporous black TiO2 nanotubes heterojunctions (Ag-MBTHs) are fabricated through surface hydrogenation, wet-impregnation and photoreduction strategy. The as-prepared Ag-MBTHs possess a relatively high specific surface area of ~85 m2 g-1 and an average pore size of ~13.2 nm. The Ag-MBTHs with narrow bandgap of ~2.63 eV extend the photoresponse from UV to visible light and near-infrared (NIR) region, which exhibit excellent visible-NIR-driven photothermal catalytic and photocatalytic performance for complete conversion nitro aromatic compounds (100%) and mineralization of high-toxic phenol (100%). The enhancement can be attributed to the mesoporous hollow structures increasing the light multi-refraction, the Ti3+ in frameworks and the surface plasmon resonance (SPR) effect of plasmonic Ag nanoparticles favoring light-harvesting and spatial separation of photogenerated electron-hole pairs, which is confirmed by transient fluorescence. The fabrication of this novel SPR-enhanced visible-NIR-driven Ag-MBTHs catalyst may provide new insights for designing other high-performance heterojunctions photocatalytic and photothermal catalytic nanomaterials.
关键词： mesoporous black TiO2 nanotube,photothermal catalysis,surface plasmon resonance,Photocatalysis,heterojunction
更新于2025-09-23 15:21:01
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Symmetric and antisymmetric surface plasmon polariton solitons in a metal-dielectric-metal waveguide with incoherent pumping
摘要： We propose a scheme to realize stable linear and nonlinear propagation of symmetric and antisymmetric surface plasmon polaritons (SPPs) solitons by doping ladder-type three-level quantum emitters into the middle layer of a metal-dielectric-metal (MDM) waveguide. In linear propagation regime, we show that both symmetric and antisymmetric SPPs can acquire a gain from electromagnetically induced transparency (EIT) effect with an incoherent pumping. The EIT can be used not only to completely compensate the Ohmic loss in the metal but also to acquire a subluminal group velocity for the SPPs. We also show that in nonlinear propagation regime a huge enhancement of Kerr nonlinearity of the symmetric and antisymmetric SPPs can be obtained but with different incoherent pumping intensities. As a result, gain-assisted (1+1)-dimensional symmetric and antisymmetric subluminal surface polaritonic solitons may be produced based on the strong confinement of electric field in the MDM waveguide. Our study may have promising applications in light information processing and transmission at nanoscale level based on MDM waveguides.
关键词： solitons,surface plasmon polaritons,electromagnetically induced transparency,Kerr nonlinearity,metal-dielectric-metal waveguide
更新于2025-09-23 15:21:01
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Nonlinear Optics || Nonlinear Optics of Plasmonic Systems
摘要： In the present chapter we explore the optical properties of plasmonic systems. The word plasmonics is often associated with the properties of metals. The reason for this association is that both the electrical and optical properties of metals are intimately related to the large number of nearly free electrons present in the conduction band of a metal. In this chapter we will primarily be concerned with the optical properties of metals, although the fundamental results that we obtain equally well describe the optical properties of other types of plasmas. The properties of nearly free electrons have been described earlier in this book, for instance as a limiting case of the Lorentz model described in Section 1.4 and also in terms of relativistic effects of plasmas as described in Section 13.7. The present chapter seeks to describe the properties of plasmonic systems in a cohesive manner. Part of the reason for interest in plasmonic systems is that they display very strong light-matter coupling, and this strong coupling leads to both linear and nonlinear properties that can be qualitatively different from those of nonplasmonic systems. This coupling leads for example to a propagating wave, known as a surface plasmon polariton (SPP), which is a mixed excitation of both electron and electromagnetic ?eld oscillations. Plasmonic systems also tend to display large nonlinear optical effects, both because metals often possess a large value ofχ (3) and because for the case of composite systems electric ?elds tend to become enhanced in regions near a metallic particle. More detailed accounts of the the role of plasmonics in nonlinear optics can be found in the accounts of Kauranen and Zayats (2012), Maier (2007), and Novotny and Hecht (2006a).
关键词： surface plasmon polariton,Drude model,plasmonics,gold,nonlinear optics
更新于2025-09-23 15:21:01
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Terahertz Optoelectronics in Graphene
摘要： Graphene has attracted considerable attention due to its extraordinary carrier transport, optoelectronic, and plasmonic properties originated from its gapless and linear energy spectra enabling various functionalities with extremely high quantum efficiencies that could never be obtained in any existing materials. This paper reviews recent advances in graphene optoelectronics particularly focused on the physics and device functionalities in the terahertz (THz) electromagnetic spectral range. Optical response of graphene is characterized by its optical conductivity and nonequilibrium carrier energy relaxation dynamics, enabling amplification of THz radiation when it is optically or electrically pumped. Current-injection THz lasing has been realized very recently. Graphene plasmon polaritons can greatly enhance the THz light and graphene matter interaction, enabling giant enhancement in detector responsivity as well as amplifier/laser gain. Graphene-based van der Waals heterostructures could give more interesting and energy-efficient functionalities.
关键词： graphene,plasmon,terahertz,laser,optoelectronics
更新于2025-09-23 15:21:01
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Surface-plasmon-coupled chemiluminescence amplification of silver nanoparticles modified immunosensor for high-throughput ultrasensitive detection of multiple mycotoxins
摘要： A novel surface-plasmon-coupled chemiluminescent immunosensor was developed for the detection of multiplex mycotoxins with ultrahigh sensitivity, high throughput and simplicity. The immunosensor was constructed by immobilizing carboxyl modified silver nanoparticles (AgNPs) and bovine serum albumin combined antigens sequentially on the glass chip modified with amino groups. The optical properties of AgNPs could amplify the chemiluminescence (CL) generated on the chip through the surface plasmon resonance phenomenon. Using a competitive immunoassay, the CL signals from all the sensing sites on the chip were collected simultaneously by a charge-coupled device for ultrasensitive analysis of multiple mycotoxins. Citrinin, aflatoxin B1 and ochratoxins A were selected as model analytes. Under optimal conditions, the surface-plasmon-coupled chemiluminescent immunosensor-based method presented wide linear ranges over 4 orders of magnitude and much lower limits of detection than previous work. The assay results of mycotoxins in red yeast rice samples using the proposed method were in good agreement with that using the liquid chromatography-mass spectrometry method. Its high selectivity, high throughput, acceptable stability and accuracy showed broad prospects in mycotoxin monitoring and evaluation of safety on Traditional Chinese Medicine.
关键词： Immunosensor array,Signal amplification,Silver nanoparticle,Multiplex immunoassay,Mycotoxins,Surface-plasmon-coupled chemiluminescence
更新于2025-09-23 15:21:01
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Broadband Plasmonic Polarization Filter Based on Photonic Crystal Fiber with Dual-Ring Gold Layer
摘要： Polarization ?lter is a very important optical device with extinction characteristics. Due to the design ?exibility of photonic crystal ?bers and the high excitation losses of the gold layer, the polarization ?lter based on the photonic crystal ?ber and surface plasmonic resonance e?ect is widely studied. Considering these, we present a simple and high-performance polarization ?lter using the ?nite element method. Numerical simulations show that there is a large di?erence in energy between the two polarization directions by reasonable adjustment of the structural parameters, the con?nement loss in the x-pol direction is less than that in the y-pol direction, which is suitable to realize a broadband polarization ?lter. When the ?ber length is 2 mm, the extinction ratio peak can reach ?478 dB, and the bandwidth with the extinction ratio better than ?20 dB is 750 nm, which covers communication wavelengths of 1.31 μm and 1.55 μm (1.05–1.8 μm). It also has a low insertion loss of 0.11 dB at 1.31 μm and 0.04 dB at 1.55 μm. In addition, our design has high feasibility in fabrication and better tolerance. The proposed ?lter with compactness, high extinction ratio, broad bandwidth, and low insertion loss would play an important role in the sensing detection, bio-medical, and telecommunication ?eld.
关键词： extinction ratio,photonic crystal ?ber,con?nement loss,polarization ?lter,surface plasmon resonance
更新于2025-09-23 15:21:01
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Ultrafast energy absorption and photoexcitation of bulk plasmon in crystalline silicon subjected to intense near-infrared ultrashort laser pulses
摘要： We investigate the non-linear response and energy absorption in bulk silicon irradiated by intense 12-fs near-infrared laser pulses. Depending on the laser intensity, we distinguish two regimes of non-linear absorption of the laser energy: for low intensities, energy deposition and photoionization involve perturbative three-photon transition through the direct bandgap of silicon. For laser intensities near and above 1014 W/cm2, corresponding to photocarrier density of order 1022 cm?3, we find that absorption at near-infrared wavelengths is greatly enhanced due to excitation of bulk plasmon resonance. In this regime, the energy transfer to electrons exceeds a few times the thermal melting threshold of Si. The optical reflectivity of the photoexcited solid is found in good qualitative agreement with existing experimental data. In particular, the model predicts that the main features of the reflectivity curve of photoexcited Si as a function of the laser fluence are determined by the competition between state and band filling associated with Pauli exclusion principle and Drude free-carrier response. The non-linear response of the photoexcited solid is also investigated for irradiation of silicon with a sequence of two strong and temporary non-overlapping pulses. The cumulative effect of the two pulses is non-additive in terms of deposited energy. Photoionization and energy absorption on the leading edge of the second pulse is greatly enhanced due to free carrier absorption.
关键词： bulk silicon,optical reflectivity,photoexcited solid,near-infrared laser pulses,Drude free-carrier response,non-linear response,energy absorption,plasmon resonance
更新于2025-09-23 15:21:01
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Recent advances of plasmonic nanoparticle-based optical analysis in homogeneous solution and at the single-nanoparticle level
摘要： Plasmonic nanoparticles with special localized surface plasmon resonance (LSPR) characters have been widely applied for optical sensing of various targets. With the combination of single nanoparticle imaging techniques, dynamic information of reactions and biological processes is obtained, facilitating the deep understanding of their principle and design of outstanding nanomaterials. In this review, we summarize the recently adopted optical analysis of diverse analytes based on plasmonic nanoparticles in both homogeneous solution and single-nanoparticle level. A brief introduction of LSPR is first discussed. Colorimetric and fluorimetric homogeneous detection examples by using different sensing mechanisms and strategies are provided. Single plasmonic nanoparticle-based analysis is concluded in two aspects: visualization of chemical reactions and understanding of biological processes. The basic sensing mechanisms and performances of these systems are introduced. Finally, this review highlights the challenges and future trend of plasmonic nanoparticle-based optical analysis system.
关键词： Plasmonic nanoparticles,Single-nanoparticle level,Fluorimetric assays,Chemical reactions,Localized surface plasmon resonance (LSPR),Optical analysis,Homogeneous solution,Colorimetric assays,Biological processes
更新于2025-09-23 15:21:01
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Fluorometric determination of morphine via its effect on the quenching of fluorescein by gold nanoparticles through a surface energy transfer process
摘要： A method is described for sensitive and selective fluorometric determination of morphine. It is based on the effect of morphine on quenching of the fluorescence of fluorescein by gold nanoparticles (AuNPs) via surface energy transfer. When fluorescein is added to solutions of colloidal AuNPs, its fluorescence becomes quenched due to nanometal surface energy transfer (NSET) because the absorption of AuNPs strongly overlaps the emission spectrum of fluorescein. In the presence of morphine, which contains both a tertiary nitrogen ring atom and a phenolic hydroxy group, it will coordinate to the AuNPs, and this causes recovery of fluorescence. The presence of a tertiary nitrogen ring atom and a phenolic hydroxy group (both required for the effect to occur) in morphine make the probe highly selective and sensitive for morphine. A paper strip assay also was developed by utilizing this detection scheme. The turn-on fluorescent probe was successfully applied to the determination of morphine in spiked serum and urine samples. The method has a 53 pM limit of detection. The paper strip was applied to the determination of morphine in sweat, urine and other biological fluids. It is perceived to be useful for early detection of drug abuse by adolescent.
关键词： Dynamic quenching,Neurotransmitter,Anesthetic drug,Paper-strip assay,Surface plasmon resonance,Stern-Volmer plot
更新于2025-09-23 15:21:01