Surface-Enhanced Raman Scattering – Physics and Applications

Kneipp, Katrin; Moskovits, Martin; Kneipp, Harald

doi:10.1007/11663898

Cited by 120 publications

(2 citation statements)

References 31 publications

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“…There is sufficient evidence of the increase in light radiation at infrared frequencies and visible by the effects of the surfaces on which they affect, such as the case of Raman scattering. [14] When light interacts with matter, it can disperse inelastically from vibrational quantum states. During this process, the photons can lose energy, or gain it from vibratory excitations, and it can also produce a concomitant change in the scattered frequency.…”

Section: Metallic Surfacesmentioning

confidence: 99%

Study of Non-predictive Patterns of Non-Ionizing Radiation in the City of Salta in Argentine

Cruz¹,

Breslin²

2020

Ionizing and Non-Ionizing Radiation

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Non-ionizing radiation (NIR) is a subject of continuous debate despite having been regulated internationally and at the level of organizations in all countries. This debate is focused on the level of population exposure to non-ionizing radiation density, since there is no certain evidence of the level of safety of the values adopted ranging from 0.2 mW/cm 2 to 0.2 uW/cm 2 according to the regulations of each state. The radiation precisions are made with models that evolve to take into account most of the factors that can attenuate the radiation emitted from an antenna from free space to models that take reflection and diffraction as attenuation factors. However, our work deepens in a phenomenon that is verified in measurement campaigns that is one of the values that do not fit with predictive models and that, on the contrary instead of showing attenuation, have higher values than expected. This work shows the results of observation campaigns of these points and their relationship with environmental conditions, which present diverse probabilities to explain their condition.

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Section: Metallic Surfacesmentioning

confidence: 99%

Study of Non-predictive Patterns of Non-Ionizing Radiation in the City of Salta in Argentine

Cruz¹,

Breslin²

2020

Ionizing and Non-Ionizing Radiation

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“…[4][5][6] The latter involves charge transfer excitation between analyte molecules (i.e., molecules of interest) and the metal particles that they coat in nanostructures such as nanowires. (The closer an analyte is to the SERSenhancing metal nanostructure, the stronger the SERS effect, hence the coating.…”

Section: On-wire Lithography Is a New Nanofabrication Technique That mentioning

confidence: 99%

Designing nanostructures with optimized surface-enhanced Raman scattering behavior

Banholzer¹,

Millstone²,

Qin

et al. 2008

SPIE Newsroom

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On-wire lithography is a new nanofabrication technique that can be used to design functionalized nanowires for both encoding and biosensing applications.Investigations in the burgeoning field of nanophotonics have demonstrated that certain nanostructures act in previously unanticipated ways. One such behavior is surface-enhanced Raman scattering (SERS), an area of substantial interest, as demonstrated by the hundreds of scientific papers published on the subject during the past 5 years. SERS was discovered over 3 decades ago. 1-3 It transforms the basic Raman technique (a measure of the structure and properties of molecules based on their interaction with light that normally has very weak intensity relative to other spectroscopies) into one that has highly sensitive detection capabilities. Whereas Raman scattering is useful for analyzing the structure of small molecules and for addressing traditional analytical issues such as a material's composition in bulk, SERS promises advances in ultrasensitive detection of a variety of molecule classes. The most important among these are biomolecules such as DNA, RNA, and proteins. Such detection capabilities (which can approach single-molecule limits) could lead to very sensitive and even mobile medical diagnostic assays. Yet the SERS phenomenon is still perplexing to scientists.The enhanced effect is most commonly attributed to electromagnetic or chemical mechanisms. [4][5][6] The latter involves charge transfer excitation between analyte molecules (i.e., molecules of interest) and the metal particles that they coat in nanostructures such as nanowires. (The closer an analyte is to the SERSenhancing metal nanostructure, the stronger the SERS effect, hence the coating. Coating is used for detection beyond SERS as well.) The electromagnetic mechanism is dominated by plasmon excitation, leading to 'hot spots' of Raman signals around nanosized metal particles. In SERS, these signals are highly ampli- fied, generating a signal orders of magnitude more intense than a nonenhanced Raman signal. Together with the unique molecular fingerprints provided by Raman spectra, SERS signals constitute an extraordinarily powerful detection and spectroscopic modality that few other techniques can match in terms of sensitivity and data density. However, optimizing and harnessing this phenomenon have proven difficult, due in part to nanostructure morphology, which significantly affects optical properties. The fabrication of nanoparticles with controllable structures is therefore extremely important for understanding and exploiting SERS fully. 7 Our group recently developed a process called on-wire lithography (OWL) that allows fabrication of 1D nanowires with nanoscale gaps along the long axis of the wire (see Figure 1). 8 The process starts with the synthesis of a segmented nanorod, consisting, for example, of alternating gold and nickel segments electrochemically grown on a template such as anodized aluminum oxide, which contains cylindrical pores. Some segments (e.g., nickel) are deliberate...

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