Mechanical modeling and optimized design of in-plane fabry–perot cavities for polymer swelling sensing

We report on the mechanical modeling and optimization of a polymer-functionalized in-plane Fabry-Perot interferometer (FPI) with a deformable silicon mirror for swelling-based sensing. An analytical model links polymer properties and cavity geometry to device mechanical sensitivity, identifying the mirror flexibility as the dominant factor. To further increase mechanical sensitivity, we introduce a new design consisting of a partitioned polymer microchannel. Simulations and fabricated devices confirm the models, showing up a twofold sensitivity gain. These results provide general design rules and experimental validation for mechanically enhanced polymer-based FPIs, advancing their use in integrated environmental and gas sensors.