The demonstrated Raman microprobe uses optical fibers and GRIN lenses to focus an exciting laser and record Raman scattering. Due to the small size of the optical components, the two parts are spatially separated; therefore much specular light or diffused light is removed from the collected light. Five collecting channels are used to increase the collecting efficiency. Experiments show that the stray light is efficiently reduced and the intensity of the Raman signal is more than ten times higher than the intensity of the spectrum obtained with a conventional Raman microscope. An exciting spot of less than 9 μm in diameter is obtained.
