Ultrafine Fiber Raman Probe with High Spatial Resolution and Fluorescence Noise Reduction

Considerable interest has been shown in fiber Raman probes as powerful tools for in situ biomedical diagnosis and monitoring processes in the materials industry. Miniaturization and high spatial resolution are required for less invasive measurements with accurate locations. In analysis of organs, widespread visible excitation light produces problematic fluorescence backgrounds. Here, we report an ultrafine fiber Raman probe that is thinner than the needle of a mosquito (labrum: 50–80 μm in diameter) with high spatial resolution (23 μm) and with a function of fluorescence background reduction. Due to the fineness and resolution, the distribution of ions in an electrolyte solution in narrow spaces could be measured. Backgrounds in spectra of liquid containing fluorescent impurity were reduced by using the probe. The probe has wide applicability for noninvasive in situ molecular diagnosis of organs and small devices.