Improving mechanical sensor performance through larger damping

Abstract

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.

Integrated nano-optomechanical displacement sensor with ultrawide optical bandwidth

“…Recently, nanophotonic cavities have shown the potential for highresolution displacement sensing on an integrated chip [3][4][5][6][7][8][9][10][11][12] . sensitivity is realized by micro-rings 3,8 , micro-disks [4][5][6][7] and photonic crystal cavities [9][10][11][12] with optical quality factors up to hundreds of thousands. However, the resonant nature of the cavity response intrinsically limits the dynamic range and the optical bandwidth, putting stringent requirements on the read-out system.…”

Recent advances in mechanical torque studies of small-scale magnetism

“…At one end, using strongly coupled optomechanical systems allow the quantum regime of micro-scale mechanical objects to be accessed. At the other end, using weakly coupled optomechanical systems provides such significant enhancement in the displacement sensitivity of a nanomechanical device that its thermomechanical noise becomes the limiting noise source -even at room temperature and atmospheric pressure [3,51]. Although design and fabrication restrictions may make it difficult to implement strongly coupled optomechanical systems in all experiments, the sensitivity improvements (even in modest systems) make it an enticing technique.…”

“…Ongoing advances in the miniaturization and sensing of mechanical devices have set forth stimulating and exciting explorations into a vast range of scientific fundamental inquiries and applications such as atomic mass sensing [2,3], observation and control of quantum phenomena [4,5], metrology [6,7], and imminent photonics-based [8,9] devices. A subset of these investigations are seeking a further understanding of small-scale magnetism through the detection of mechanical torques transduced via magnetic spins, which contain direct information about the magnetization and related static and dynamic processes.…”

Nanomechanical Sensors as a Tool for Bacteria Detection and Antibiotic Susceptibility Testing

“…In contrast to micro-or nano-meter resonators, millimeter-sized cantilevers present a high Reynold number, causing a hydrodynamics behavior dominated by inertial forces (Mutharasan, 2008). In a recent publication, the relation between Q and the signalto-noise ratio (SNR) is reanalyzed, finding that the frequency stability of resonant nanomechanical sensors can be improved by lowering the quality factor (Roy et al, 2018). The authors confirm that Q and SNR behave inversely for intrinsically limited resonators and find stability improved with damping, which open the door to high-performance ultrasensitive resonators in liquid environments.…”