Raman Spectroscopy Research Paper

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Abstract 200 words approx Raman spectroscopy has made a profound impact on the development of analytical techniques Introduction Overview of Raman Spectroscopy Spectroscopy, in its most simple terms, involves measuring the interaction of radiation with matter to obtain information about a sample. Raman spectroscopy is one of many spectroscopic techniques; it observes the rotational and vibrational modes of a system through the interaction of radiation with electron density and molecular bonds. Raman spectroscopy is a two-photon event, in which the polarizability of the molecule is changed by the incoming radiation of frequency and there is an induced dipole moment. The outgoing light by the induced dipole moment contains both elastic and…show more content…
There are many variations on the definition of a plasmon, depending on your interest. Plasmons are somewhat to plasmas, what photons are to electromagnetic fields. In this context, a plasma can be defined as a cloud of free electrons (from gold or silver metal) that reside among fixed positive ions, contributing to overall neutrality. Plasmons result from the quantization of the rapid oscillations of electrons in the plasma. These plasmons propagate in along the intereface of the structure. The types of plasmons are too numerous to discuss here. The only types of plasmons that play a significant role in SERS are surface plasmons, and more specifically, localised surface plasmons (LSP) and propagating surface plasmons (PSP). When light is incident on a spherical metallic nanoparticle(much smaller than the wavelength of incident light) the oscillating electric field excite the surface plasmons and cause them to oscillate coherently. This is outlined in Figure…show more content…
It was found that both the in plane and the out of plane diameters of the periodic structure obtained after removal of the mask can be carefully controlled. The Van Duyne group [169] was able to examine the relationship between the LSPR extinction maximum and the SERS enhancement factor using this substrate and an EF of 108 has been reported The necessity for a highly reproducible SERS substrate motivated the use of visible light lithography on Si supports in the development of a commercially viable SERS substrate. The photolithography resulted in conic micro-wells with 2_m pitch; Gold was evaporated on the drawn Si substrate. The resulting substrate presents highly reproducible SERS performance and it has been patented by the authors [170,171]. This substrate had been commercially available initially by a spin-off enterprise by the University of Southampton under the designation of KlariteTM; nowadays it is marketed by the Renishaw, Inc. Although the KlariteTM substrate does not present a SERS-EF in the

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