Spin detection with a micromechanical trampoline: towards magnetic resonance microscopy harnessing cavity optomechanics

• Published in: New journal of physics Vol. 21; no. 4; pp. 43049 - 43061
• Main Authors: Fischer, R, McNally, D P, Reetz, C, Assumpção, G G T, Knief, T, Lin, Y, Regal, C A
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 26.04.2019
• Subjects: Cavity resonators; Cryogenic cooling; Cryogenic temperature; Electron paramagnetic resonance; Electron spin; magnetic resonance force microscopy (MRFM); membrane-in-the-middle; Membranes; Microscopy; Opto-mechanics; optomechanics; Physics; Q factors; Room temperature; Silicon nitride; Sound waves; Spin resonance
• ISSN: 1367-2630; 1367-2630
• DOI: 10.1088/1367-2630/ab117a

We explore the prospects and benefits of combining the techniques of cavity optomechanics with efforts to image spins using magnetic resonance force microscopy (MRFM). In particular, we focus on a common mechanical resonator used in cavity optomechanics-high-stress stoichiometric silicon nitride (Si3N4) membranes. We present experimental work with a 'trampoline' membrane resonator that has a quality factor above 106 and an order of magnitude lower mass than a comparable standard membrane resonators. Such high-stress resonators are on a trajectory to reach 0.1 aN Hz force sensitivities at MHz frequencies by using techniques such as soft clamping and phononic-crystal control of acoustic radiation in combination with cryogenic cooling. We present a demonstration of force-detected electron spin resonance of an ensemble at room temperature using the trampoline resonators functionalized with a magnetic grain. We discuss prospects for combining such a resonator with an integrated Fabry-Perot cavity readout at cryogenic temperatures, and provide ideas for future impacts of membrane cavity optomechanical devices on MRFM of nuclear spins.