Single-molecule Optical Absorption Imaging by Nanomechanical Photothermal Sensing at Room Temperature

Abstract

A novel nanomechanical absorption-based microscopy with unprecedented sensitivity of 16 fW/Hz1/2 and position accuracy of 30 nm is introduced with silicon nitride drum resonator. [1] The imaging of nanoparticles with diameter of 10 nm - 200 nm and single molecules is demonstrated. A systematic discussion on the optimization of sensitivity by stress engineering is also performed both experimentally and theoretically. With the applicability, 5-order-ofmagnitudes higher sensitivity comparing with the state-of-the-art detection scheme, and outstanding spatial resolution, this study provides a simple alternative for qualitative and quantitative analysis and imaging of single molecules without labeling, which could potentially unveil the underlying nanoscale dynamics as well as providing a new robust microscopy with high precision and accuracy.