Abstract

Absorption microscopy is a powerful technique, enabling the detection of single non-fluorescent molecules at room temperature. We show that nanomechanical photothermal sensing surpasses the shot-noise-limited sensitivity of state-of-the-art optical absorption techniques by more than two orders of magnitude. Using stress-optimized silicon nitride resonators, we achieve femtowatt-sensitivities at room temperature. Such a sensitivity results in unprecedented signal-to-noise ratios for the imaging of single molecules, presenting a competitive alternative to established imaging tools for single-molecule analysis.