The Raman depolarization ratio is a quantity that can be easily measured experimentally and offers unique information on the Raman polarizability tensor of molecular vibrations. In Surface Enhanced Raman Scattering (SERS), molecules are near-field coupled with optical nanoantennas and their scattering properties are strongly affected by the radiation patterns of the nanoantenna. The polarization of the SERS photons is consequently modified, affecting, in a non trivial way, the measured value of the SERS depolarization ratio. In this article we elaborate a model that describes how the SERS depolarization ratio is influenced by the nanoantenna re-radiation properties, suggesting how to retrieve information on the Raman polarizability from SERS experiments.
The magnetic domain structure and Raman scattering have been studied in NiO single-crystals with three different (100), (110) and (111) orientations. Twin-domain structure was observed in NiO(100) and NiO(110) single-crystals using cross-polarized optical microscopy. We found that the ratio of the two-magnon (at 1500 cm−1) to the two-phonon (2LO, at 1100 cm−1) Raman bands intensity is sensitive in a particular way to the type of the twin-domain pattern.
Zero phonon line (ZPL) shape, position and integral intensity of SiV defect center in diamond is presented for nanocrystalline diamond (NCD) films grown at different conditions, NCD films of average grain sizes from ~50 nm up to ~180 nm have been deposited onto c-Si wafer at substrate temperature of 700 and 850oC from mixture with different CH4 and H2 ratios using MWCVD process. Light emission of SiV defect center and Raman scattering properties of NCD samples were measured on a Renishaw micro-Raman spectrometer with 488 nm excitation. Scanning electron microscopy images were used for monitoring surface morphology and for the analysis of the average grain sizes. Sample thickness was determined by in situ laser reflection interferometry. Characteristics of SiV ZPL are discussed in light of the morphology, bonding structure and average grain size of NCD films.
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