Coupled mechanical oscillator enables precise detection of nanowire flexural vibrations

• Published in: Communications physics Vol. 6; no. 1; pp. 352 - 7
• Main Authors: Sharma, Maneesha, Sathyadharma Prasad, Aniruddha, Freitag, Norbert H., Büchner, Bernd, Mühl, Thomas
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.12.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/925/927/356; 639/925/927/359; Coupling; Deflection; Diameters; Electric fields; Field emission; Laser beam heating; Mechanical oscillators; Nanowires; Physics; Physics and Astronomy; Room temperature; Scanning probe microscopes; Vibration measurement; Vibration mode
• ISSN: 2399-3650; 2399-3650
• DOI: 10.1038/s42005-023-01466-9

The field of nanowire (NW) technology represents an exciting and steadily growing research area with applications in ultra-sensitive mass and force sensing. Existing detection methods for NW deflection and oscillation include optical and field emission approaches. However, they are challenging for detecting small diameter NWs because of the heating produced by the laser beam and the impact of the high electric field. Alternatively, the deflection of a NW can be detected indirectly by co-resonantly coupling the NW to a cantilever and measuring it using a scanning probe microscope. Here, we prove experimentally that co-resonantly coupled devices are sensitive to small force derivatives similar to standalone NWs. We detect force derivatives as small as 10 −9  N/m with a bandwidth of 1 Hz at room temperature. Furthermore, the measured hybrid vibration modes show clear signatures of avoided crossing. The detection technique presented in this work verifies a major step in boosting NW-based force and mass sensing. Flexural oscillations of singly-clamped nanowires can be detected by interferometry for diameters above 50 nm, while below such diameter the detection becomes challenging. The authors detect force derivatives as small as 10-9 N/m at room temperature by measuring hybrid vibration modes originated by coupling a nanowire and a cantilever.