Improvement and analysis of a micro Raman probe.

A micro Raman probe (MRP) with a 600 microm diameter, which we previously reported as the narrowest achieved to date, was further improved by introducing high-quality optical filters and a collecting lens at the tip. We fabricated the MRP with a high collection efficiency, a wider collection wavelength, and a high signal-to-noise ratio. We compared two types of probes: one with a lens-tipped end and one with a flat tip. We experimentally tested the performance of these MRPs to evaluate the detection properties defined by parameters such as the optical purity against inherent Raman background noise due to optical fibers, the sensitivity, and the viewing area. Finally, we demonstrated their effectiveness in measurements of standard Raman samples and applied them to measurements of plastic and human skin samples in situ.