Probing Single Molecules and Single Nanoparticles by Surface-Enhanced Raman Scattering

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In this integrated microscope ultrasensitive optical imaging and spectroscopy provided molecular information and AFM resolved the shape and size of individual nanoparticles. The microscope side port was coupled to a high-throughput single-stage spectrograph and a back-illuminated charge-coupled device (CCD) detector for spectroscopy. The microscope front was attached to a video-rate intensified CCD for wide-field imaging of single nanoparticles with epi- or evanescent-wave laser excitation. A tapping-mode AFM scanning head was mounted directly on the microscope stage for topographic imaging at nanometer-scale resolution. When coupled with a video data acquisition system this apparatus allowed digital movies to be made of single nanoparticles at 30 frames per second. Detailed instrument diagram and specifications are available upon request.

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S.N. acknowledges the Whitaker Foundation for a Biomedical Engineering Award and the Beckman Foundation for a Beckman Young Investigator Award. This work was supported by Indiana University Startup Funds.