Determining the direction of a nanowire's flexural vibrations by micro-lens optical fiber interferometer

TL;DR

This paper introduces a novel optical fiber interferometry method to determine the vibration directions of nanowires without needing to detect orthogonal modes simultaneously, enhancing nanowire vibration characterization.

Contribution

The work presents a new optical interferometry technique that identifies nanowire vibration directions without requiring detection of degenerated orthogonal modes, simplifying the process.

Findings

Successfully demonstrated the method with experimental results.

The method does not require detecting two orthogonal vibration modes.

Potential for wide applications in nanowire vibration analysis.

Abstract

Nanowires are perfect transducers for ultra-sensitive detections of force and mass. For small mass sensing, recent advances in detecting more properties than their masses with high sensitivity for absorbed particles onto a nanowire rely on identifications of two orthogonal flexural vibration modes of the nanowire. The directions of these orthogonal flexural vibrations with respect to measurement direction are crucial parameters of vibration modes. However, previous method, which determines a nanowire's vibration direction using thermal vibrations, requires simultaneously detecting of two orthogonal flexural vibrations of the nanowire with sufficient sensitivity. In this work, we propose and realize a method for the determination of directions of a nanowire's flexural vibrations by micro-lens optical fiber interferometer. Our method combines the light interference and light scattering of the nanowire. It does not require detecting a pair of degenerated orthogonal flexural vibration modes. Therefore, our method is expected to have wide usages in characterizing nanowire's vibrations and their applications.