Details

Autor(en) / Beteiligte

• Fabelinsky, Victor I.
• Kozlov, Dimitrii N.
• Polivanov, Yury N.
• Smirnov, Valery V.
• Bokova‐Sirosh, Sofia N.
• Obraztsova, Elena D.
• Arzumanyan, Grigory M.
• Mamatkulov, Kahramon Z.
• Afanasiev, Konstantin N.
• Boginskaya, Irina A.
• Budashov, Igor A.
• Nechaeva, Natalia L.

Titel

Laser intensity limits in surface‐enhanced linear and nonlinear Raman micro‐spectroscopy of organic molecule/Au‐nanoparticle conjugates

Ist Teil von

• Journal of Raman spectroscopy, 2019-09, Vol.50 (9), p.1311-1320

Ort / Verlag

Bognor Regis: Wiley Subscription Services, Inc

Erscheinungsjahr

2019

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• Laser light, illuminating surface‐enhanced Raman scattering‐active nanostructured CeO2/Al/Al2O3 thin‐film samples with reporter molecules/Au nanoparticle conjugates on the CeO2 surface, may cause irreversible modifications of the conjugates and of the surface structure field‐enhancing properties. As a result, the observed Raman signal decreases or vanishes. The limits of the laser light intensity suitable for nondestructive spectroscopic studies have been assessed using continuous and quasi‐continuous wave (mode‐locked ps‐pulse) laser radiation at different wavelengths. This radiation was used as a pump for linear and nonlinear Raman microspectroscopy of reporter molecules adsorbed on the surface of such a plasmonic metamaterial. Reducing laser power below certain levels allowed reproducible mapping of surface‐enhanced Raman scattering and surface‐enhanced coherent anti‐Stokes Raman scattering signal strengths at the reporter molecule Raman shifts. Surface‐enhanced Raman scattering (SERS)‐active Au nanoparticles/CeO2/Al/Al2O3 metamaterial surface with 5‐thio(2‐nitrobenzoic acid) reporter molecules bound to these Au nanoparticles was investigated using SERS excited at 532, 633, and 785 nm, and surface‐enhanced coherent anti‐Stokes Raman scattering (SECARS) at 931 and 1064 nm pump pair. The intensity limits for obtaining reproducible results were experimentally evaluated for continuous wave or quasi‐continuous wave picosecond laser beams. SERS and SECARS mappings of the surface clearly show that the higher is the signal in a hot spot at minimal laser intensities, the earlier it becomes saturated or disappears when the intensities increase.