A Raman-atomic force microscope for apertureless-near-field spectroscopy and optical trapping

An instrument that combines the analytical power of Raman spectroscopy with the spatial resolution of the Atomic Force Microscope (AFM) is presented. This instrument is capable of resolving 50 nm scale spectral features or better by using surface enhanced Raman scattering at the AFM tip. The localized spectrochemical information allows the interpretation of the concurrently acquired friction or phase contrast AFM images. This instrument has a unique combination of features including side illumination of the tip-sample interface that permits opaque samples. As a result of precise focusing of a laser at the AFM tip-sample interface this instrument is also capable of laser beam profiling and studying optical trapping at the probe tip. Applications of this versatile instrument include chemical analysis of nanometer scale phenomena, chemical separation, and the potential for targeted single molecule spectroscopy. (C) 2002 American Institute of Physics.