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Author Tamma, Venkata Ananth ♦ Huang, Fei ♦ Wickramasinghe, H. Kumar ♦ Nowak, Derek
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ ATOMIC FORCE MICROSCOPY ♦ DETECTION ♦ DIFFRACTION ♦ GAIN ♦ LASERS ♦ METALS ♦ MOLECULES ♦ OPTICAL SPECTROMETERS ♦ OPTIMIZATION ♦ PHENYLALANINE ♦ PHOTONS ♦ RAMAN SPECTROSCOPY ♦ SENSITIVITY ♦ SPATIAL RESOLUTION
Abstract We report on stimulated Raman spectroscopy and nanoscopy of molecules, excited without resonant electronic enhancement gain, and recorded using near field photon induced forces. Photon-induced interaction forces between the sharp metal coated silicon tip of an Atomic Force Microscope (AFM) and a sample resulting from stimulated Raman excitation were detected. We controlled the tip to sample spacing using the higher order flexural eigenmodes of the AFM cantilever, enabling the tip to come very close to the sample. As a result, the detection sensitivity was increased compared with previous work on Raman force microscopy. Raman vibrational spectra of azobenzene thiol and l-phenylalanine were measured and found to agree well with published results. Near-field force detection eliminates the need for far-field optical spectrometer detection. Recorded images show spatial resolution far below the optical diffraction limit. Further optimization and use of ultrafast pulsed lasers could push the detection sensitivity towards the single molecule limit.
ISSN 00036951
Educational Use Research
Learning Resource Type Article
Publisher Date 2016-06-06
Publisher Place United States
Journal Applied Physics Letters
Volume Number 108
Issue Number 23


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