title: Ultrabroadband infrared nanospectroscopic imaging.
abstract: Characterizing and ultimately controlling the heterogeneity underlying biomolecular functions, quantum behavior of complex matter, photonic materials, or catalysis requires large-scale spectroscopic imaging with simultaneous specificity to structure, phase, and chemical composition at nanometer spatial resolution. However, as with any ultrahigh spatial resolution microscopy technique, the associated demand for an increase in both spatial and spectral bandwidth often leads to a decrease in desired sensitivity. We overcome this limitation in infrared vibrational scattering-scanning probe near-field optical microscopy using synchrotron midinfrared radiation. Tip-enhanced localized light-matter interaction is induced by low-noise, broadband, and spatially coherent synchrotron light of high spectral irradiance, and the near-field signal is sensitively detected using heterodyne interferometric amplification. We achieve sub-40-nm spatially resolved, molecular, and phonon vibrational spectroscopic imaging, with rapid spectral acquisition, spanning the full midinfrared (700-5,000 cm(-1)) with few cm(-1) spectral resolution. We demonstrate the performance of synchrotron infrared nanospectroscopy on semiconductor, biomineral, and protein nanostructures, providing vibrational chemical imaging with subzeptomole sensitivity.
authors.affiliation: Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; habechtel@lbl.gov mcmartin@lbl.gov markus.raschke@colorado.edu.
authors.forename: Hans A
authors.initials: HA
authors.lastname: Bechtel
authors.affiliation: Departments of Physics andChemistry, University of Colorado, Boulder, CO 80309; andJILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Muller
authors.affiliation: Departments of Physics andChemistry, University of Colorado, Boulder, CO 80309; andJILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Olmon
authors.affiliation: Advanced Light Source Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; habechtel@lbl.gov mcmartin@lbl.gov markus.raschke@colorado.edu.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Martin
authors.affiliation: Departments of Physics andChemistry, University of Colorado, Boulder, CO 80309; andJILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309 habechtel@lbl.gov mcmartin@lbl.gov markus.raschke@colorado.edu.
authors.forename: Markus B
authors.initials: MB
authors.lastname: Raschke
mesh_terms: D004583:Electrons; D005583:Fourier Analysis; D007368:Interferometry / Q000379:methods; D008027:Light; D008853:Microscopy / Q000379:methods*; D018625:Microscopy, Atomic Force / Q000379:methods; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D060739:Phonons; D015203:Reproducibility of Results; D012666:Semiconductors; D012815:Signal Processing, Computer-Assisted; D012822:Silicon Dioxide / Q000737:chemistry; D013055:Spectrophotometry, Infrared / Q000295:instrumentation / Q000379:methods*; D013499:Surface Properties; D017356:Synchrotrons; D014732:Vibration
chemical_list: D012822:Silicon Dioxide
keywords: bioimaging; chemical identification; nano-FTIR