Polarization-Dependent Surface-Enhanced Raman Scattering via Aligned Gold Nanorods in Poly(Vinyl Alcohol) Film

Abstract

A low-cost and effective surface-enhanced Raman scattering (SERS) substrate consisting of aligned gold nanorods is obtained by stretching the poly(vinyl alcohol) nanorods composite film doped with the probe molecule. The SERS intensity of characteristic vibrational band of the probe is observed obviously dependent on the angle (θ) between incident polarization and major axis of nanorod. The relationship between them manifests a cos 2 θ dependence. The result is illustrated from both the localized field enhancement and optical antenna effect of gold nanorod. The finite element method calculation is also performed to further confirm the conclusion.

Single gold trimers and 3D superstructures exhibit a polarization-independent SERS response

“…Several groups have simulated and measured the scattering spectra of dimers, 6-13 trimers [13][14][15] and superstructures. 16 The optical response of a dimer (D Nh symmetry) is highly polarization-dependent, 6,[17][18][19][20] similar to nanorods, 21,22 particle-nanowire systems, 23,24 and nanoparticle arrays. 25,26 In contrast, this polarization dependence does not occur for spherical particles.…”

Au nanoparticle-encapsulated hydrogel substrates for robust and reproducible SERS measurement

“…[7][8][9] Recently, the strategy of directly embedding nanostructures in a polymer matrix for SERS substrates has drawn attention since it could be one of the practical approaches to make SERS measurements more reliable for many analytical applications. [10][11][12][13][14][15] Several SERS substrates, such as Ag nanoparticle-loaded agarose gel, Ag nanoparticle-or Ag nanorod-embedded PVA nanobers, and a capillary tube lled with a Ag nanoparticle-embedded polymer monolith, have recently been demonstrated. [10][11][12][13][14][15] The requirements of a reliable nanostructure-holding polymer matrix for SERS measurement are facile access of an analyte into a matrix as well as physical sustainability of the polymeric structure without serious degradation or rupture upon sample uptake.…”

“…[10][11][12][13][14][15] Several SERS substrates, such as Ag nanoparticle-loaded agarose gel, Ag nanoparticle-or Ag nanorod-embedded PVA nanobers, and a capillary tube lled with a Ag nanoparticle-embedded polymer monolith, have recently been demonstrated. [10][11][12][13][14][15] The requirements of a reliable nanostructure-holding polymer matrix for SERS measurement are facile access of an analyte into a matrix as well as physical sustainability of the polymeric structure without serious degradation or rupture upon sample uptake. A hydrogel is a suitable choice for the polymer matrix since it has a superior ability of water uptake; 16,17 therefore, it has been effectively used in Raman spectroscopy as a substrate for surface enhanced Raman optical activity (SEROA) to study enantiomers (Dand L-ribose) 18 and nondestructive identication of colorants in art works by SERS.…”

Quantification of Interface-Dependent Plasmon Quality Factors Using Single-Beam Nonlinear Optical Interferometry

“…10,11 Because of their large local field enhancement and tunable resonance frequencies, plasmonic nanostructures are routinely applied to increase optical signal amplitudes in surfaceenhanced spectroscopy and imaging measurements. [4][5][6][7]12 These effects have also been leveraged to increase the spatial localization accuracies and precisions of optical microscopes. 5−7 An important consideration for the use of plasmonic nanostructures in these applications is the mode quality factor (Q-factor), which describes the enhancement of the oscillation amplitude of a driven oscillating system with respect to the driving amplitude.…”

“…The localized surface plasmon resonance (LSPR) of colloidal nanoparticles provides many opportunities to use electromagnetic transduction in analytical chemistry. − The LSPR is a coherent electronic transition, resulting from collective excitation of conduction band electrons. In nanoparticles (NPs), this excitation induces local surface fields with resonance frequencies that depend on NP composition, size, geometry, and dielectric environment. , As such, the LSPR frequency is a sensitive indicator of analyte binding events. , Because of their large local field enhancement and tunable resonance frequencies, plasmonic nanostructures are routinely applied to increase optical signal amplitudes in surface-enhanced spectroscopy and imaging measurements. − , These effects have also been leveraged to increase the spatial localization accuracies and precisions of optical microscopes. − An important consideration for the use of plasmonic nanostructures in these applications is the mode quality factor (Q-factor), which describes the enhancement of the oscillation amplitude of a driven oscillating system with respect to the driving amplitude. − A large Q-factor tends to result in greater field enhancement and narrow resonator line width, both of which are favored for applications of plasmonic materials. A key factor that limits plasmonic Q-factors is the ultrafast electronic decoherence of photoexcited conduction band electrons, typically within 10s of femtoseconds.…”