Mechanical reconfigurable infrared filter for stress sensing applications

In this study, we introduce a novel tunable infrared filter design aimed at stress sensor applications such as health monitoring, advanced robotics and industrial automation. The design utilizes a double-layer plasmonic frequency-selective surface (FSS) of indium tin oxide (ITO) with an aerogel inter-space region. The unique feature of this design is its ability to control the transmission pattern based on the stress exerted, which alters the distance between the two filter layers. Our approach employs both numerical simulations and a simplified model grounded in equivalent circuit theory and the transfer matrix method for accurate transmission pattern estimation where the sensor achieved a sensitivity of 20nm/MPa for average stress of 14MPa and spectrum range ( \(\lambda >800 nm\) $\lambda >800nm$ ). The work provides an in-depth analysis of how layer dimensions and inter-layer distance influence both transmission and force, taking into account the elastic properties of the inter-space material.