TY - JOUR A1 - Ruzankina, Iuliia A1 - Mukhin, Nikolay A1 - Mermoul, Ali A1 - Parfenov, Vadim A1 - Fron, Eduard A1 - Ferrini, Gabriele T1 - Surface optical sensitivity enhanced by a single dielectric microsphere JF - Optics Express N2 - Single dielectric microspheres can manipulate light focusing and collection to enhance optical interaction with surfaces. To demonstrate this principle, we experimentally investigate the enhancement of the Raman signal collected by a single dielectric microsphere, with a radius much larger than the exciting laser spot size, residing on the sample surface. The absolute microsphere-assisted Raman signal from a single graphene layer measured in air is more than a factor of two higher than that obtained with a high numerical aperture objective. Results from Mie’s theory are used to benchmark numerical simulations and an analytical model to describe the isolated microsphere focusing properties. The analytical model and the numerical simulations justify the Raman signal enhancement measured in the microsphere-assisted Raman spectroscopy experiments. Y1 - 2022 UR - https://doi.org/10.1364/OE.472720 VL - 30 IS - 24 SP - 43021 EP - 43036 PB - Optica ER -