Near-Field Infrared Pump–Probe Imaging of Surface Phonon Coupling in Boron Nitride Nanotubes
journal contributionposted on 07.01.2016, 12:05 by Leonid Gilburd, Xiaoji G. Xu, Yoshio Bando, Dmitri Golberg, Gilbert C. Walker
Surface phonon modes are lattice vibrational modes of a solid surface. Two common surface modes, called longitudinal and transverse optical modes, exhibit lattice vibration along or perpendicular to the direction of the wave. We report a two-color, infrared pump-infrared probe technique based on scattering type near-field optical microscopy (s-SNOM) to spatially resolve coupling between surface phonon modes. Spatially varying couplings between the longitudinal optical and surface phonon polariton modes of boron nitride nanotubes are observed, and a simple model is proposed.