Use of a mechanical iris-based fiber optic probe for spatially offset Raman spectroscopy.

We demonstrated a mechanical iris-based fiber optic probe with adjustable spatial offsets for spatially offset Raman spectroscopy (SORS). In the fiber probe, the excitation fiber was fixed at the center of the iris, and the collection fibers were movable with blades of the iris. Moreover, we studied the gap effect between the probe and the sample and demonstrated this fiber optic probe can be used as a platform for surface-enhanced SORS applications. This fiber probe design could potentially provide a design-efficient and cost-effective solution for various Raman applications.