scholarly journals Excitation Conditions for Surface-Enhanced Hyper Raman Scattering With Biocompatible Gold Nanosubstrates

2021 ◽  
Vol 9 ◽  
Author(s):  
Arpad Dusa ◽  
Fani Madzharova ◽  
Janina Kneipp
Keyword(s):  
Raman Scattering ◽  
Short Wave ◽  
Two Photon ◽  
Surface Sensitivity ◽  
Electromagnetic Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Excitation Laser ◽  
Enhanced Raman Scattering ◽  
Difference Time

Surface enhanced hyper Raman scattering (SEHRS) can provide many advantages to probing of biological samples due to unique surface sensitivity and vibrational information complementary to surface-enhanced Raman scattering (SERS). To explore the conditions for an optimum electromagnetic enhancement of SEHRS by dimers of biocompatible gold nanospheres and gold nanorods, finite-difference time-domain (FDTD) simulations were carried out for a broad range of excitation wavelengths from the visible through the short-wave infrared (SWIR). The results confirm an important contribution by the enhancement of the intensity of the laser field, due to the two-photon, non-linear excitation of the effect. For excitation laser wavelengths above 1,000 nm, the hyper Raman scattering (HRS) field determines the enhancement in SEHRS significantly, despite its linear contribution, due to resonances of the HRS light with plasmon modes of the gold nanodimers. The high robustness of the SEHRS enhancement across the SWIR wavelength range can compensate for variations in the optical properties of gold nanostructures in real biological environments.

scholarly journals Probing the plasmonic near-field by one- and two-photon excited surface enhanced Raman scattering

2013 ◽  
Vol 4 ◽  
pp. 834-842 ◽  
Author(s):  
Katrin Kneipp ◽  
Harald Kneipp
Keyword(s):  
Raman Scattering ◽  
Photon Energy ◽  
Near Field ◽  
Single Molecules ◽  
Surface Enhanced Raman Scattering ◽  
Plasmonic Nanostructures ◽  
Two Photon ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Strongly enhanced and spatially confined near-fields in the vicinity of plasmonic nanostructures open up exciting new capabilities for photon-driven processes and particularly also for optical spectroscopy. Surface enhanced Raman signatures of single molecules can provide us with important information about the optical near-field. We discuss one- and two-photon excited surface enhanced Raman scattering at the level of single molecules as a tool for probing the plasmonic near-field of silver nanoaggregates. The experiments reveal enhancement factors of local fields in the hottest hot spots of the near-field and their dependence on the photon energy. Also, the number of the hottest spots and their approximate geometrical size are found. Near-field amplitudes in the hottest spots can be enhanced by three orders of magnitudes. Nanoaggregates of 100 nm dimensions provide one hot spot on this highest enhancement level where the enhancement is confined within less than 1nm dimension. The near-field enhancement in the hottest spots increases with decreasing photon energy.

Molecular hot spots in surface-enhanced Raman scattering

Nanoscale ◽  
2020 ◽  
Vol 12 (43) ◽  
pp. 22036-22041
Author(s):  
Ming Li ◽  
Scott K. Cushing ◽  
Guangwen Zhou ◽  
Nianqiang Wu
Keyword(s):  
Raman Scattering ◽  
Hot Spots ◽  
Surface Enhanced Raman Scattering ◽  
Aromatic Molecules ◽  
Electromagnetic Enhancement ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

This work reports that aromatic molecules adsorbed on the Au surface can create “molecular hot spots” for electromagnetic enhancement of surface-enhanced Raman scattering.

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