Comparison of key modalities of micro-scale spatially offset Raman spectroscopy

摘要: We compare several basic embodiments of a recently proposed and demonstrated micrometer-scale Spatially Offset Raman Spectroscopy (micro-SORS). Micro-SORS is introduced analytical method for noninvasive characterisation the chemical composition subsurface, micrometre-scale-thick diffusely scattering layers at depths beyond reach conventional confocal microscopy. The technique applicable, example, in nondestructive subsurface analysis highly stratified matrices such as painted cultural heritage or polymer systems biological samples. Using Monte Carlo simulations, we analysed two defocusing variants micro-SORS variant involving full separation illumination collection zones on sample surface. Both penetration depth into relative enhancement sublayer signals were studied function layer thickness type their parameters. model predicts that most effective by far with fully spatially separated zones. On other hand, micro-SORS, where both laser are defocussed overlapped, yielded lowest performance although its key benefit lies simplicity concept can be practiced existing microscopes without any modifications. A experimental verification theoretical findings contrasting extreme modalities, one, also presented.