Work

Slot-mode cantilever optomechanical system for mass sensing

Year: 2026

Type: article

Abstract: We present a slot-mode optomechanical platform that integrates a one-dimensional photonic crystal (PhC) cavity with a cantilever (CL) mechanical resonator. This architecture enables a high optomechanical coupling value (G/2 π = 0.80 GHz/nm) while maintaining a low effective motional mass ( m eff = 13 fg), essential for high-sensitivity mass sensing. In contrast to typical slot-mode designs based on doubly clamped beams, the use of a cantilever offers reduced mass and enhanced dynamic range. We fabricate devices using silicon-on-insulator substrates and demonstrate coupling between MHz-frequency cantilever modes and localized THz optical modes. Through thermomechanical noise analysis and phase-locked loop frequency tracking, we estimate a mass sensitivity level of ≈30 zg. We also identify potential dominant noise sources, including temperature-driven cavity frequency fluctuations, and propose practical routes toward sub-zeptogram sensitivity through improvements in optomechanical coupling and cavity quality factor.

Source: Optics Express

DOI: 10.1364/oe.582111

Authors: C. Thrideep, M. Belov, W. K. Hiebert

Institution: University of Alberta

Language: English

Topic: Mechanical and Optical Resonators

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funders: Alberta Innovates, Natural Sciences and Engineering Research Council of Canada