Multimode nanoelectromechanical systems (NEMS) based mass sensor; the main figure schematically depicts a doubly-clamped beam vibrating in fundamental mode (1). Conceptual "snapshots" of the first six vibrational modes are shown below (1-6), colors indicate high (red) to low (blue) strain. The inset shows a colorized electron micrograph of a piezoelectric NEMS resonator fabricated in Caltech's Kavli Nanoscience Institute.
M. Matheny, L.G. Villanueva, P. Hung, J. Li and M. Roukes/Caltech