Plasmonic nanosponges

Wang, Dong; Schaaf, Peter

doi:10.1080/23746149.2018.1456361

Cited by 25 publications

(30 citation statements)

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“…Nonlinear light emission from localized plasmonic hot spots. For our studies of nonlinear plasmon-exciton coupling, we take gold nanosponges-porous half-spherical nanoparticles with diameters of several hundreds of nanometers-as a promising plasmonic nanoantenna 21 . Such nanosponges are perforated with 10-20 nm sized nanopores throughout the entire particle, forming a randomly disordered ligament network (see scanning electron microscopy (SEM) image in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Nonlinear plasmon-exciton coupling enhances sum-frequency generation from a hybrid metal/semiconductor nanostructure

Zhong

Vogelsang

et al. 2020

Nat Commun

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The integration of metallic plasmonic nanoantennas with quantum emitters can dramatically enhance coherent harmonic generation, often resulting from the coupling of fundamental plasmonic fields to higher-energy, electronic or excitonic transitions of quantum emitters. The ultrafast optical dynamics of such hybrid plasmon-emitter systems have rarely been explored. Here, we study those dynamics by interferometrically probing nonlinear optical emission from individual porous gold nanosponges infiltrated with zinc oxide (ZnO) emitters. Few-femtosecond time-resolved photoelectron emission microscopy reveals multiple longlived localized plasmonic hot spot modes, at the surface of the randomly disordered nanosponges, that are resonant in a broad spectral range. The locally enhanced plasmonic near-field couples to the ZnO excitons, enhancing sum-frequency generation from individual hot spots and boosting resonant excitonic emission. The quantum pathways of the coupling are uncovered from a two-dimensional spectrum correlating fundamental plasmonic excitations to nonlinearly driven excitonic emissions. Our results offer new opportunities for enhancing and coherently controlling optical nonlinearities by exploiting nonlinear plasmonquantum emitter coupling.

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Section: Resultsmentioning

confidence: 99%

“…Preparation of nanosponges. Gold nanosponges were synthesized in two steps 21,45 . First, gold-silver alloy nanoparticles with (sub)micron diameters were fabricated by solid-state dewetting of a bimetallic Au/Ag (8 nm/20 nm thick) thin film on a SiO 2 /Si substrate.…”

Section: Methodsmentioning

confidence: 99%

Nonlinear plasmon-exciton coupling enhances sum-frequency generation from a hybrid metal/semiconductor nanostructure

Zhong

Vogelsang

et al. 2020

Nat Commun

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“…We involve this optimisation into the implementation of additive sharing scheme in the finite field Z 2 31 , the addition (multiplication) operations is calculated by several regular addition and multiplication operations with the modulo operation. Oblivious Transfer and Garbled Circuit are implemented by using FlexSC [61]. It implements the extended OTs in [2] and several optimisations for the garbled circuit, which make it a practical primitive under Java environment.…”

Section: Methodsmentioning

confidence: 99%

GraphSE²

Lai

Yuan

Sun

et al. 2019

Proceedings of the 2019 ACM Asia Conference on Computer and Communications Security

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In this paper, we propose GraphSE 2 , an encrypted graph database for online social network services to address massive data breaches. GraphSE 2 preserves the functionality of social search, a key enabler for quality social network services, where social search queries are conducted on a large-scale social graph and meanwhile perform set and computational operations on user-generated contents. To enable efficient privacy-preserving social search, GraphSE 2 provides an encrypted structural data model to facilitate parallel and encrypted graph data access. It is also designed to decompose complex social search queries into atomic operations and realise them via interchangeable protocols in a fast and scalable manner. We build GraphSE 2 with various queries supported in the Facebook graph search engine and implement a full-fledged prototype. Extensive evaluations on Azure Cloud demonstrate that GraphSE 2 is practical for querying a social graph with a million of users. CCS CONCEPTS• Security and privacy → Management and querying of encrypted data; Social network security and privacy; Privacypreserving protocols;

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“…In addition, the pore volume depends on the amount of the less noble element in the starting alloy. This approach works for Ag-Au bulk alloy leafs (i.e., thin foils, typically 50-100 µm thick, made by hammering) [20][21][22][23][24][25]28,[31][32][33][34][35][36][37][38][41][42][43][44][45], films [20][21][22][23][24][25]29,39,40], and nanostructures [20][21][22][23][24][25]30,[92][93][94][95][96][97][98][99][100][101][102][103]. Several excellent reviews describe the thermodynamics and kinetic processes involved in the dealloying mechanism of alloys toward the formation of NPG…”

Section: Nanoporous Gold: General Considerationsmentioning

confidence: 99%

“…The exceptional optical properties of NPG find promising applications in optical sensors [20][21][22][23][24][25][26][93][94][95][96][97][98][99][100][101][102]. When the dimensions of metals such as Au are reduced to the scale of the mean free path of electrons within the material, the oscillations of electrons generate localized surface plasmon resonance (LSPR) [14,15].…”

Section: Optical Sensingmentioning

confidence: 99%

Nanoporous Gold-Based Sensing

Ruffino

Grimaldi

2020

Coatings

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In recent years, the field of nanoporous metals has undergone accelerated developments as these materials possess high specific surface areas, well-defined pore sizes, functional sites, and a wide range of functional properties. Nanoporous gold (NPG) is, surely, the most attractive system in the class of nanoporous metals: it combines several desired characteristics as occurrence of surface plasmon resonances, enormous surface area, electrochemical activity, biocompatibility, in addition to feasibility in preparation. All these properties concur in the exploitatiton of NPG as an efficient and versatile sensong platform. In this regard, NPG-based sensors have shown exceptional sensitivity and selectivity to a wide range of analytes ranging from molecules to biomolecules (and until the single molecule detection) and the enormous surface/volume ratio was shown to be crucial in determining these performances. Thanks to these characteristics, NPG-based sensors are finding applications in medical, biological, and safety fields so as in medical diagnostics and monitoring processes. So, a rapidly growing literature is currently investigating the properties of NPG systems toward the detection of a multitude of classes of analytes highlighting strengths and limits. Due to the extension, complexity, and importance of this research field, in the present review we attempt, starting from the discussion of specific cases, to focus our attention on the basic properties of NPG in connection to the main sensing applications, i.e., surface enhanced Raman spectroscopy-based and electrochemical-based sensing. Owing to the nano-sized pore channels and Au ligaments, which are much smaller than the wavelength of visible light (400–700 nm), surface plasmon resonances of NPG can be effectively excited by visible light and presents unique features compared with other nanostructured metals, such as nanoparticles, nanorods, and nanowires. This characteristics leads to optical sensors exploiting NPG through unique surface plasmon resonance properties that can be monitored by UV-Vis, Raman, or fluorescence spectroscopy. On the other hand, the catalytic properties of NPG are exploited electrochemical sensors are on the electrical signal produced by a specific analyte adsorbed of the NPG surface. In this regard, the enourmous NPG surface area is crucial in determining the sensitivity enhancement. Due to the extension, complexity, and importance of the NPG-based sensing field, in the present review we attempt, starting from the discussion of specific cases, to focus our attention on the basic properties of NPG in connection to the main sensing applications, i.e., surface enhanced Raman spectroscopy-based and electrochemical-based sensing. Starting from the discussion of the basic morphological/structural characteristics of NPG as obtained during the fabrication step and post-fabrication processes, the review aims to a comprehensive schematization of the main classes of sensing applications highlighting the basic involved physico-chemical properties and mechanisms. In each discussed specific example, the main involved parameters and processes governing the sensing mechanism are elucidated. In this way, the review aims at establishing a general framework connecting the processes parameters to the characteristics (pore size, etc.) of the NPG. Some examples are discussed concerning surface plasmon enhanced Uv-Vis, Raman, fluorescence spectroscopy in order to realize efficient NPG-based optical sesnors: in this regard, the underlaying connections between NPG structural/morphological properties and the optical response and, hence, the optical-based sensing performances are described and analyzed. Some other examples are discussed concerning the exploitation of the electrochemical characteristics of NPG for ultra-high sensitivity detection of analytes: in this regard, the key parameters determing the NPG activity and selectivity selectivity toward a variety of reactants are discussed, as high surface-to-volume ratio and the low coordination of surface atoms. In addition to the use of standard NPG films and leafs as sensing platforms, also the role of hybrid NPG-based nanocomposites and of nanoporous Au nanostructures is discussed due to the additional increase of the electrocatalytic acticvity and of exposed surface area resulting in the possible further sensitivity increase.

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Plasmonic nanosponges

Cited by 25 publications

References 76 publications

Nonlinear plasmon-exciton coupling enhances sum-frequency generation from a hybrid metal/semiconductor nanostructure

Nonlinear plasmon-exciton coupling enhances sum-frequency generation from a hybrid metal/semiconductor nanostructure

GraphSE²

Nanoporous Gold-Based Sensing

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