scholarly journals Localized surface plasmon resonances in nanostructures to enhance nonlinear vibrational spectroscopies: towards an astonishing molecular sensitivity

2014 ◽  
Vol 5 ◽  
pp. 2275-2292 ◽  
Author(s):  
Dan Lis ◽  
Francesca Cecchet
Keyword(s):  
Raman Scattering ◽  
Surface Plasmon ◽  
Single Molecule ◽  
Nonlinear Optical ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Surface Enhanced ◽  
Plasmon Resonances ◽  
Vibrational Spectroscopies ◽  
Vibrational Transitions

Vibrational transitions contain some of the richest fingerprints of molecules and materials, providing considerable physicochemical information. Vibrational transitions can be characterized by different spectroscopies, and alternatively by several imaging techniques enabling to reach sub-microscopic spatial resolution. In a quest to always push forward the detection limit and to lower the number of needed vibrational oscillators to get a reliable signal or imaging contrast, surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators. Another approach is based on maximizing the collective response of the excited vibrational oscillators through molecular coherence. Both features are often naturally combined in vibrational nonlinear optical techniques. In this frame, this paper reviews the main achievements of the two most common vibrational nonlinear optical spectroscopies, namely surface-enhanced sum-frequency generation (SE-SFG) and surface-enhanced coherent anti-Stokes Raman scattering (SE-CARS). They can be considered as the nonlinear counterpart and/or combination of the linear surface-enhanced infrared absorption (SEIRA) and surface-enhanced Raman scattering (SERS) techniques, respectively, which are themselves a branching of the conventional IR and spontaneous Raman spectroscopies. Compared to their linear equivalent, those nonlinear vibrational spectroscopies have proved to reach higher sensitivity down to the single molecule level, opening the way to astonishing perspectives for molecular analysis.

scholarly journals Multiple surface plasmon resonances enhanced nonlinear optical microscopy

Nanophotonics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 487-493 ◽  
Author(s):  
Xiaohu Mi ◽  
Yuyang Wang ◽  
Rui Li ◽  
Mengtao Sun ◽  
Zhenglong Zhang ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Optical Microscopy ◽  
Surface Plasmon ◽  
Nonlinear Optical ◽  
Surface Plasmon Resonances ◽  
Nonlinear Optical Microscopy ◽  
Two Photon ◽  
Plasmon Resonances ◽  
Anti Stokes ◽  
Multiple Surface Plasmon Resonances

AbstractThe nonlinear optical microscopies of coherent two-photon excited fluorescence and anti-Stokes Raman scattering are strongly enhanced by multiple surface plasmon resonances (MSPRs). The Au@Ag nanorods presented strong MSPRs peaks at 800 and 400 nm, and can enhance nonlinear optical microscopy at fundamental and double frequencies, respectively. A two-dimensional (2D) material of g-C3N4 is employed to study the plasmon-enhanced nonlinear optical microscopy by the femtosecond laser. The electric analysis reveals that the MSPRs of the Au@Ag nanorod can significantly enhance the signals of two-photon excited fluorescence and anti-Stokes Raman scattering by up to the orders of 104 and 1016, respectively. The results demonstrate the great advantages of plasmon-enhanced nonlinear optical microscopy for the optical analysis on 2D materials, thus providing a new adventure for increasing the optical resolutions of nonlinear optical microscopy.

scholarly journals Surface Plasmon Resonances in Silver Nanostars

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3821 ◽  
Author(s):  
Faustino Reyes Gómez ◽  
Rafael Rubira ◽  
Sabrina Camacho ◽  
Cibely Martin ◽  
Robson da Silva ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Time Domain ◽  
Finite Difference Time Domain ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Sensing Applications ◽  
Surface Enhanced ◽  
Plasmon Resonances ◽  
Difference Time

The recent development of silver nanostars (Ag-NSs) is promising for improved surface-enhanced sensing and spectroscopy, which may be further exploited if the mechanisms behind the excitation of localized surface plasmon resonances (LSPRs) are identified. Here, we show that LSPRs in Ag-NSs can be obtained with finite-difference time-domain (FDTD) calculations by considering the nanostars as combination of crossed nanorods (Ag-NRs). In particular, we demonstrate that an apparent tail at large wavelengths ( λ ≳ 700 nm) observed in the extinction spectra of Ag-NSs is due to a strong dipolar plasmon resonance, with no need to invoke heterogeneity (different number of arms) effects as is normally done in the literature. Our description also indicates a way to tune the strongest LSPR at desired wavelengths, which is useful for sensing applications.

scholarly journals Space- and time-resolved second harmonic spectroscopy of coupled plasmonic nanocavities

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adi Salomon ◽  
Heiko Kollmann ◽  
Manfred Mascheck ◽  
Slawa Schmidt ◽  
Yehiam Prior ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Plasmon ◽  
Nonlinear Optical ◽  
Second Harmonic ◽  
Hot Spot ◽  
Localized Surface Plasmon ◽  
Surface Plasmon Resonances ◽  
Localized Surface Plasmon Resonances ◽  
Plasmon Resonances ◽  
Linear And Nonlinear

Abstract Localized surface plasmon resonances of individual sub-wavelength cavities milled in metallic films can couple to each other to form a collective behavior. This coupling leads to a delocalization of the plasmon field at the film surface and drastically alters both the linear and nonlinear optical properties of the sample. In periodic arrays of nanocavities, the coupling results in the formation of propagating surface plasmon polaritons (SPP), eigenmodes extending across the array. When artificially introducing dislocations, defects and imperfections, multiple scattering of these SPP modes can lead to hot-spot formation, intense and spatially confined fluctuations of the local plasmonic field within the array. Here, we study the underlying coupling effects by probing plasmonic modes in well-defined individual triangular dimer cavities and in arrays of triangular cavities with and without artificial defects. Nonlinear confocal spectro-microscopy is employed to map the second harmonic (SH) radiation from these systems. Pronounced spatial localization of the SPP field and significant enhancements of the SH intensity in certain, randomly distributed hot spots by more than an order of magnitude are observed from the triangular arrays as compared to a bare silver film by introducing a finite degree of disorder into the array structure. Hot-spot formation and the resulting enhancement of the nonlinear efficiency are correlated with an increase in the lifetime of the localized SPP modes. By using interferometric SH autocorrelation measurements, we reveal lifetimes of hot-spot resonances in disordered arrays that are much longer than the few-femtosecond lifetimes of the localized surface plasmon resonances of individual nanocavity dimers. This suggests that hot spot lifetime engineering provides a path for manipulating the linear and nonlinear optical properties of nanosystems by jointly exploiting coherent couplings and tailored disorder.

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