Abstract This paper presents a proposed tri-axis optomechanical accelerometer integrating a monolithic single-proof-mass MEMS suspension with an engineered metal–insulator–metal (MIM) plasmonic platform. The device utilizes a modified frog-arm spring system, optimized via finite element simulations to provide near-identical peak displacements (\: \: 200\: nm) and mechanical sensitivities (\: S₌\: 100\: nm/g) within a \: \: 2\: g range, operating across a bandwidth of \: \: 473\: Hz. Structural stability is verified through pre-stressed analysis, showing negligible warpage (\: \: 1\: nm) and a substantial safety factor (\: \: 10^4), while maintaining minimal axis interference with cross-axis coupling \: <0. 2\%. The optical transduction, analyzed through finite-difference time-domain (FDTD) methods, employs a Hybrid Plasmonic Waveguide (HPW) configuration to induce a pronounced Fano-type resonance with an insertion loss of \: \: -6. 29\: dB across the visible-to-near-infrared spectrum (\: 500-1500\: nm). By adopting an asymmetric structural architecture, the sensor generates direction-sensitive signatures characterized through a Bidirectional Optical Sensitivity Matrix, which maps nanoscale displacements to simultaneous wavelength and intensity modulation. This framework facilitates the discrimination of acceleration polarities (± X, ±Y, ±Z) and yields a balanced tri-axis Full Scale Normalized Optical Sensitivity (FS-NOS) of \: \: 0. 002\: nm^-1. Systematic noise analysis reveals a NEA of \: \: 0. 78\: \: g/Hz, supporting sub-µg resolution, while the minimum optical resolution for the Y-axis is calculated as \: 61. 07\: \: g. Furthermore, a sequential hierarchical decoupling approach is proposed to reconstruct 3D acceleration vectors from superimposed optical outputs. This work establishes a versatile framework for developing high-resolution, all-optical, EMI-immune plasmonic MOEMS tailored for precision inertial sensing.
Farrokhi et al. (Sat,) studied this question.