Abstract
In force sensing, optomechanics, and quantum motion experiments, it is typically advantageous to create lightweight, compliant mechanical elements with the lowest possible force noise. Here, we report the fabrication and characterization of high-aspect-ratio, nanogram-scale “trampolines” having quality factors above and ringdown times exceeding 5 min (mHz linewidth). These devices exhibit thermally limited force noise sensitivities below at room temperature, which is the lowest among solid-state mechanical sensors. We also characterize the suitability of these devices for high-finesse cavity readout and optomechanics applications, finding no evidence of surface or bulk optical losses from the processed nitride in a cavity achieving finesse 40,000. These parameters provide access to a single-photon cooperativity in the resolved-sideband limit, wherein a variety of outstanding optomechanics goals become feasible.
- Received 5 November 2015
DOI:https://doi.org/10.1103/PhysRevX.6.021001
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Published by the American Physical Society
Physics Subject Headings (PhySH)
Erratum
Erratum: Ultralow-Noise SiN Trampoline Resonators for Sensing and Optomechanics [Phys. Rev. X 6, 021001 (2016)]
Christoph Reinhardt, Tina Müller, Alexandre Bourassa, and Jack C. Sankey
Phys. Rev. X 7, 039901 (2017)
Viewpoint
Trampolines Sense a Disturbance in the Force
Published 18 April 2016
Researchers have engineered trampoline resonators that may be able to sense extremely weak forces and display quantum behavior at ambient temperatures.
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Popular Summary
Ultrasensitive force measurements and optomechanics experiments typically call for lightweight, low-noise, and optically pristine mechanical elements. Here, we present delicate, nanogram-scale “trampoline” mechanical sensors achieving attonewton force sensitivity and extremely low optical absorption. The demonstrated parameters will, in principle, enable extremely low levels of laser light (i.e., an average of a single photon) to strongly influence their mechanical trajectories.
Our batch-fabricated sensors comprise a sub-100-nm-thick “pad” supported by millimeter-long, microns-wide “tethers” fabricated from silicon nitride. In vacuum , these structures ring for approximately 6 min and are accordingly sensitive to attonewton forces at room temperature. Additionally, the spring constants of these sensors are 2–4 orders of magnitude larger than those of comparably sensitive devices, making them promising candidates for nanoscale sensing geometries in which floppier cantilevers might stick to the sample. Their comparatively large surface area provides a platform upon which a wide variety of probes or other on-chip systems can be fabricated, which makes them well suited for many force sensing and materials dissipation studies. Finally, we show that these devices absorb very little light at telecom wavelengths, making them compatible with ultrasensitive interferometry and optomechanics experiments.
We expect that our work will pave the way for future studies of quantum motion with macroscopic solid objects.