Force sensing with nanowire cantilevers

Abstract

Nanometer-scale structures with high aspect ratio such as nanowires and nanotubes combine low mechanical dissipation with high resonance frequencies, making them ideal force transducers and scanning probes in applications requiring the highest sensitivity. Such structures promise record force sensitivities combined with ease of use in scanning probe microscopes. A wide variety of possible material compositions and functionalizations is available, allowing for the sensing of various kinds of forces with optimized sensitivity. In addition, nanowires possess quasi-degenerate mechanical mode doublets, which has allowed the demonstration of sensitive vectorial force and mass detection. These developments have driven researchers to use nanowire cantilevers in various force sensing applications, which include imaging of sample surface topography, detection of optomechanical, electrical, and magnetic forces, and magnetic resonance force microscopy. In this review, we discuss the motivation behind using nanowires as force transducers, explain the methods of force sensing with nanowire cantilevers, and give an overview of the experimental progress and future prospects of the field.

Theory of quantum acoustomagnonics and acoustomechanics with a micromagnet

“…This is shown in Fig. 10, where we display the power spectral density at T e = 300K, Q p = 10 7 , and a moderate value Q x = 10 5 , reachable in most experimental platforms [80, [88][89][90][91][92]. Upon increasing the magnetic field gradient b, the power spectral density transitions from a single peak, corresponding to a single mechanical oscillator, at zero coupling, i.e.…”

“…10, this measurement is experimentally feasible, especially for acoustic quality factors Q p > 10 7 , as the two peaks reach values ∼ 1pm/Hz 1/2 , even when the center-of-mass motion is only driven by thermal noise. This is within the sensitivity regime of most state-of-the-art ultra-sensitive displacement sensors [79,80,88,90,91,[94][95][96][97][98] and the signal-to-noise ratio in the power spectral density can be largely increased by resonant excitation of the center-of-mass mode. Remarkably, probing the internal modes remains feasible for higher-order acoustic phonons, as evidenced by Fig.…”

Evaluation of Microfluidic Channels With Thin Si Windows and Trapping Structures

“…On the other hand, magnetic resonance force microscopy (MRFM) is an imaging technique based on highly sensitive mechanical cantilever sensing with nanometer resolution [13]- [15]. Electron spin resonance (ESR)-MRFM has been developed for the 3D imaging of biological samples [16]- [18].…”

Optical Transduction for Vertical Nanowire Resonators

“…1 Regarding dynamic properties, the characteristic high aspect ratio of SCNWs results in flexural modes which are extremely sensitive to external perturbations of a different nature. 2 On one hand, this facilitates detecting their thermomechanical vibrations, as the effect of temperature alone results in relatively large vibration amplitudes; on the other hand, it also simplifies external driving schemes, as external forces of a different nature can be used to drive flexural vibrations even beyond the fundamental mode. These properties provide SCNW resonators with singular sensing capacities which are otherwise impossible to achieve with other structures.…”