Enhancement of Raman signals : coherent Raman scattering and surface enhanced Raman spectroscopy

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dc.contributor.advisorVanden Bout, David A.en
dc.contributor.advisorLim, Sang-Hyunen
dc.contributor.committeeMemberPeter, Rossky J.en
dc.contributor.committeeMemberWillets, Katherine A.en
dc.contributor.committeeMemberLi, Xiaoqin E.en
dc.creatorChou, He-Chunen
dc.date.accessioned2012-07-06T18:57:06Zen
dc.date.accessioned2017-05-11T22:25:40Z
dc.date.available2012-07-06T18:57:06Zen
dc.date.available2017-05-11T22:25:40Z
dc.date.issued2012-05en
dc.date.submittedMay 2012en
dc.date.updated2012-07-06T18:57:31Zen
dc.descriptiontexten
dc.description.abstractRaman spectroscopy is a promising technique because it contains abundant vibrational chemical information. However, Raman spectroscopy is restricted by its small scattering cross section, and many techniques have been developed to amplify Raman scattering intensity. In this dissertation, I study two of these techniques, coherent Raman scattering and surface enhanced Raman scattering and discuss their properties. In the first part of my dissertation, I investigate two coherent Raman processes, coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS). In CARS project, I mainly focus on the molecular resonance effect on detection sensitivity, and I find the detection sensitivity can be pushed into 10 [micromolar] with the assistance of molecular resonance. Also, I am able to retrieve background-free Raman spectra from nonresonant signals. For SRS, we develop a new SRS system by applying spectral focusing mechanism technique. We examine the feasibility and sensitivity of our SRS system. The SRS spectra of standards obtained from our system is consistent with literature, and the sensitivity of our system can achieve 10 times above shot-noise limit. In second part of this dissertation, I study surface enhanced Raman scattering (SERS) and related plasmonic effects. I synthesize different shapes of nanoparticles, including nanorod, nanodimer structure with gap and pyramids by template method, and study how electric field enhancement effects correlate to SERS by two photon luminescence (TPL). Also, I build an optical system to study optical image, spectra and particle morphology together. I find that SERS intensity distribution is inhomogeneous and closely related to nanoparticle shape and polarization direction. However, TPL and SERS are not completely correlated, and I believe different relaxation pathways of TPL and SERS and coupling of LSPR and local fields at different frequencies cause unclear correlation between them.en
dc.description.departmentChemistryen
dc.format.mimetypeapplication/pdfen
dc.identifier.slug2152/ETD-UT-2012-05-5476en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2012-05-5476en
dc.language.isoengen
dc.subjectRaman spectroscopyen
dc.subjectSurface enhanced Raman spectroscopyen
dc.subjectSERSen
dc.subjectCoherent anti-Stokes Raman spectroscopyen
dc.subjectCARSen
dc.subjectStimulated Raman spectroscopyen
dc.subjectTwo photon luminescenceen
dc.subjectLocalized surface plasmon resonanceen
dc.titleEnhancement of Raman signals : coherent Raman scattering and surface enhanced Raman spectroscopyen
dc.type.genrethesisen

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