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Title: Dynamic near-field optical interaction between oscillating nanomechanical structures

Near-field optical techniques exploit light-matter interactions at small length scales for mechanical sensing and actuation of nanomechanical structures. Here, we study the optical interaction between two mechanical oscillators—a plasmonic nanofocusing probe-tip supported by a low frequency cantilever, and a high frequency nanomechanical resonator—and leverage their interaction for local detection of mechanical vibrations. The plasmonic nanofocusing probe provides a confined optical source to enhance the interaction between the two oscillators. Dynamic perturbation of the optical cavity between the probe-tip and the resonator leads to nonlinear modulation of the scattered light intensity at the sum and difference of their frequencies. This double-frequency demodulation scheme is explored to suppress unwanted background and to detect mechanical vibrations with a minimum detectable displacement sensitivity of 0.45pm/Hz 1/2, which is limited by shot noise and electrical noise. We explore the demodulation scheme for imaging the bending vibration mode shape of the resonator with a lateral spatial resolution of 20nm. We also demonstrate the time-resolved aspect of the local optical interaction by recording the ring-down vibrations of the resonator at frequencies of up to 129MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [1] ;  [3]
  1. Northwestern Univ., Evanston, IL (United States). Mechanical Engineering Dept.
  2. Argonne National Lab., Argonne, IL (United States). Center for Nanoscale Materials.
  3. Northwestern Univ., Evanston, IL (United States). Mechanical Engineering and Civil and Environmental Engineering Depts.
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 5; Journal ID: ISSN 2045-2322
Nature Publishing Group
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
77 NANOSCIENCE AND NANOTECHNOLOGY; scanning probe microscopy; super-resolution microscopy; 36 MATERIALS SCIENCE
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1332972