Controllable method for the preparation of metalized probes for efficient scanning near-field optical Raman microscopy

A modification of the mirror reaction method has been used to metalize atomic force microscope (AFM) probes for apertureless near-field optical microscopy. The method produces a single silver particle of controllable size at the apex of the AFM tip with no detrimental effects on the AFM probe. A particle of the order 80 nm in diameter appears to provide the best tip-enhanced Raman signal using 488 nm excitation. The near-field Raman spatial resolution of one such probe was shown to be as high as 24 nm using single-walled carbon nanotubes as a test sample.