Surface Enhanced Magneto-Optics in Noble Metal / Ferromagnetic Metal Multilayers

1995 ◽  
Vol 384 ◽  
Author(s):  
V. I. Safarov ◽  
V. A. Kosobukin ◽  
C. Hermann ◽  
G. Lampel ◽  
J. Peretti ◽  
...  
Keyword(s):  
Noble Metal ◽  
Figure Of Merit ◽  
Signal To Noise Ratio ◽  
Ferromagnetic Metal ◽  
Multilayer Thin Films ◽  
Kerr Rotation ◽  
Resonant Coupling ◽  
Electromagnetic Enhancement ◽  
Surface Enhanced ◽  
Resonant Feature

ABSTRACTWe present an electromagnetic enhancement mechanism for the magneto-optical response of noble metal / ferromagnetic metal multilayer thin films. When such a structure is illuminated in total reflection condition, the resonant coupling of light with the noble metal surface plasmons gives rise to an amplification of the magneto-optically induced component of the light electric field. The experimental results obtained on a 30nm-thick Au / Co / Au model system show that this resonant feature observed in the Kerr rotation and ellipticity corresponds to a strong enhancement of the magneto-optical figure of merit and signal-to-noise ratio.

scholarly journals Understanding Electromagnetic Interactions and Electron Transfer in Ga Nanoparticle–Graphene–Metal Substrate Sandwich Systems

2019 ◽  
Vol 9 (19) ◽  
pp. 4085 ◽  
Author(s):  
Yael Gutiérrez ◽  
Maria M. Giangregorio ◽  
April S. Brown ◽  
Fernando Moreno ◽  
Maria Losurdo
Keyword(s):  
Contact Angle ◽  
Electron Transfer ◽  
Noble Metal ◽  
Metal Substrate ◽  
Metal Nanoparticle ◽  
Localized Surface Plasmon ◽  
Graphene Layers ◽  
Electromagnetic Enhancement ◽  
Electromagnetic Interactions ◽  
Surface Enhanced

Plasmonic metal nanoparticle (NP)–graphene (G) systems are of great interest due their potential role in applications as surface-enhanced spectroscopies, enhanced photodetection, and photocatalysis. Most of these studies have been performed using noble metal NPs of silver and gold. However, recent studies have demonstrated that the noble metal–graphene interaction leads to strong distortions of the graphene sheet. In order to overcome this issue, we propose the use of Ga NPs that, due to their weak interaction with graphene, do not produce any deformation of the graphene layers. Here, we analyze systems consisting of Ga NP/G/metal sandwich coupling structures, with the metal substrate being, specifically, copper (Cu) and nickel (Ni), i.e., Ga NP/G/Cu and Ga NPs/G/Ni. We experimentally show through real-time plasmonic spectroscopic ellipsometry and Raman spectroscopy measurements of the quenching of the Ga NP localized surface plasmon resonance (LSPR) depending on the wetting of the graphene by the Ga NPs and on the electron transfer through graphene. Theoretical finite-difference time-domain (FDTD) simulations supportively demonstrate that the LSPR in such sandwich structures strongly depends on the contact angle of the NP with graphene. Finally, we also provide evidence of the electron transfer from the Ga NPs into the graphene and into the metal substrate according to the work function alignments. These considerations about the contact angle and, consequently, geometry and wetting of the metal NPs on graphene, are useful to guide the design of those plasmonic systems to maximize electromagnetic enhancement.

Intensity Calibration and Sensitivity Comparisons for CCD/Raman Spectrometers

1993 ◽  
Vol 47 (12) ◽  
pp. 1965-1974 ◽  
Author(s):  
Mark Fryling ◽  
Christopher J. Frank ◽  
Richard L. McCreery
Keyword(s):  
Quantum Efficiency ◽  
Figure Of Merit ◽  
Instrumental Response ◽  
Fiber Optic ◽  
Collection Efficiency ◽  
Signal To Noise Ratio ◽  
Quantitative Comparison ◽  
Sample Position ◽  
Fiber Output ◽  
Photodiode Arrays

A calibrated tungsten source combined with a fiber optic was used to correct Raman spectra for instrumental response. With the placement of the fiber output at the Raman sample position, the product of throughput, collection efficiency, quantum efficiency, and sampled area could be assessed. This product is related to a spectrometer figure of merit, which provides a quantitative comparison of spectrometer sensitivity and signal-to-noise ratio. Four spectrometer configurations were compared to illustrate the approach. An additional feature of the white light calibration is correction of relative Raman peak intensities. This issue is particularly important due to the substantial differences between CCD quantum efficiency curves and those of photomultipliers or intensified photodiode arrays.

Finite-Size Effects and Surface-Enhanced Raman Scattering in Noble-Metal Nanoparticles

2004 ◽  
Vol 818 ◽  
Author(s):  
Vitaliy N. Pustovit ◽  
Tigran V. Shahbazyan
Keyword(s):  
Raman Scattering ◽  
Metal Nanoparticles ◽  
Noble Metal ◽  
Finite Size ◽  
Surface Enhanced Raman Scattering ◽  
Noble Metal Nanoparticles ◽  
Raman Signal ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

AbstractWe study the role of a strong electron confinement on the surface-enhanced Raman scattering from molecules adsorbed on small noble-metal nanoparticles. We describe a novel enhancement mechanism which originates from the different effect that confining potential has on s-band and d-band electrons. We demonstrate that the interplay between finite-size and screening efects in the nanoparticle surface layer leads to an enhancement of the surface plasmon local field acting on a molecule located in a close proximity to the metal surface. Our calculations show that the additional enhancement of the Raman signal is especially strong for small nanometer-sized nanoparticles.

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