Dynamic near-field optical interaction between oscillating nanomechanical structures

Abstract

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 0.45 pm/Hz1/2, 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 20 nm. 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 129 MHz. The near-field optical technique is promising for studying dynamic mechanical processes in individual nanostructures.

Nanomechanical Motion Transducers for Miniaturized Mechanical Systems

“…For instance, if one actuates a mechanical structure in the in-plane direction, interferometric techniques tend to become insensitive to the mechanical motion. Recently demonstrated transduction techniques suitable for such motions are primarily based on optical scattering: optical knife-edge technique [ 105 , 106 , 107 ], and scattering enhanced with near-field optical probes and/or approaches [ 59 , 63 , 108 , 109 , 110 , 111 , 112 , 113 , 114 ].…”

High therapeutic efficacy of Cathelicidin-WA against postweaning diarrhea via inhibiting inflammation and enhancing epithelial barrier in the intestine

“…Unfortunately, the widespread use of antibiotics has increased bacterial resistance, leading to delayed administration of effective therapy as well as morbidity and mortality in both humans and animals 8 9 . As reported, antimicrobial-resistant infections cause more than 700,000 deaths each year globally: at least 23,000 in the USA and 175,000 in the EU 10 11 . Furthermore, the development of new antibiotics has slowed down, and few antibiotics have been approved by the FDA in recent years 10 .…”

“…As reported, antimicrobial-resistant infections cause more than 700,000 deaths each year globally: at least 23,000 in the USA and 175,000 in the EU 10 11 . Furthermore, the development of new antibiotics has slowed down, and few antibiotics have been approved by the FDA in recent years 10 . Moreover, recent studies have reported that therapeutic or sub-therapeutic antibiotic treatments in early life have long-term consequences on intestinal microbiota composition and metabolic homeostasis in the host 12 13 .…”

Coupling between flexural modes in free vibration of single-walled carbon nanotubes

“…Very recently, a beating response due to interference of two oscillatory modes with close frequencies has been found in a nanomechanical resonator. 23 It is important to make experimental measurements of the response of CNTs at high temperature. This should be possible having significant influence for a CNT as an AFM cantilever and a mass sensor.…”

“…[15][16][17][18] It is well known that nonlinearity may play an important role in the thermal and electrical transport of nanotubes, nanoribbons and nanowires. [19][20][21][22][23] For nonlinear vibration of CNTs actuated by a direct current (DC) or alternating current (AC) load, it has been found that the type vibration may suddenly transition from a planar motion to a whirling, "jump rope" like motion. 24,25 The effect of initial curvature of CNTs has also been investigated using a two dimensional nonlinear curved beam model, and it shows the transfer of energy among the vibration modes involved in the veering phenomenon.…”