Nano-Raman mapping of porous glass ceramics with a scanning near-field optical microscope in collection mode

A nano-Raman setup using the optical fiber of a scanning near-field optical microscope, working in collection mode, is described and applied to mapping of Ti O2 P O4 phase distribution in glass ceramics. This material is extremely important as a surface-enhanced raman scattering substrate for biological and chemical analyses. The collected Raman signal in this near-field geometry reaches spatial resolutions better than 100 nm, well below the diffraction limit.