Mechanical resonances are used in a wide variety of devices, from smartphone accelerometers to computer clocks and from wireless filters to atomic force microscopes. Frequency stability, a critical performance metric, is generally assumed to be tantamount to resonance quality factor (the inverse of the linewidth and of the damping). We show that the frequency stability of resonant nanomechanical sensors can be improved by lowering the quality factor. At high bandwidths, quality-factor reduction is completely mitigated by increases in signal-to-noise ratio. At low bandwidths, notably, increased damping leads to better stability and sensor resolution, with improvement proportional to damping. We confirm the findings by demonstrating temperature resolution of 60 microkelvin at 300-hertz bandwidth. These results open the door to high-performance ultrasensitive resonators in gaseous or liquid environments, single-cell nanocalorimetry, nanoscale gas chromatography, atmospheric-pressure nanoscale mass spectrometry, and new approaches in crystal oscillator stability.

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.

Optical interferometric techniques are used for absolute (calibrated) displacement measurements of focused ion beam (FIB)-fabricated nanoelectromechanical systems (NEMS). FIB nanomachining of bulk Si gives rapidly prototyped cantilever and doubly clamped beam devices. Ion impingement from orthogonal directions allows tailoring of deep, undercut-free gaps between the device layer and the bulk, in turn allowing large amplitude NEMS oscillatory motion, access to a nonlinear readout regime and a new calibration method for optical interferometric displacement detection. The measurements are sensitive enough to determine the thermomechanical noise floor of a bulk FIBed NEMS device with a displacement sensitivity of 166 fm Hz − 1 2 , limited by the combination of optical shot noise and detector dark current. This sensitivity, comparable to the state of the art for free-space optical interferometry of NEMS, validates the robustness of the bulk FIB fabrication technique for rapid prototyping of nanoscale mechanical devices.