Surface enhanced Raman radiation of crystal violet dye has been studied by modulating the
localized surface plasmon effect of silver nanoparticles. In the experiment, a buffer layer of silicon
dioxide (SiO2) was established between crystal violet dye and silver nanoparticles. With a probe of
laser beam of 532 nm in wavelength, it was found that the intensity of the Raman scattering
significantly depended on the thickness of SiO2 layer. A maximum Raman-radiation intensity occurred
with a 10nm-thicked SiO2 layer. The experimental observation shows a possible modulation of surface
enhanced Raman radiation by a proper dielectric buffer.
The authors presented an experimental observation of the dynamically optical response of silver
nanoparticle film. A 7nm-thicked sliver film was thermally deposited on an indium tin oxide glass
substrate and that be annealed from room temperature to 300°C. The absorbance spectra and the
dark-field micrograph of the silver nanoparticle film exhibited novel optical response, strongly
dependent on the particle geometry, from the excitation of the localized surface plasmon. In particular,
the peak wavelength and the maximum value of the absorbance and the exhibited color of the sample
changed dramatically during the heating. A convenient and non-destructive technique to directly
explore the substance in nanoscale has been achieved based on the optical analyses.
A tunable grating was fabricated with silver nanoparticles in a gradient increase of nanoparticle
size along the grating direction in this study. Owing to the gradual increment of the nanoparticle size,
the first order diffraction efficiencies of incident light presented as a function of the impinging position
of the probe beam. Via a probe of monochromatic light ranged from 450 to 750 nm, the positive and the
negative first order diffraction efficiency were measured by rotating the optical detector. It was noted
that the maximum positive and negative diffraction efficiency appeared at around 600 and 700 nm,
respectively. The difference in the peak wavelength of these two diffraction efficiency exhibited the
diffraction property was strongly affected by the gradient variation of the localized surface plasmon
effect. The first order diffraction efficiency spectra affected by the various excitations of the localized
surface plasmons with the taper size distribution of nanoparticles were the special discovery of the
study and may lead to a potential development in light modulation and manipulation.
The optical diffraction efficiency of lithographic grating was probed in this study. The enhanced
first order spectral diffraction efficiency emerged from localized surface-plasmon excitation of gold
nanoparticles which are alternatively uniformly and randomly spread in grating strips. The sensible
measurement more than traditional method is reported.