Advancing optomechanical sensing: Novel CMOS-compatible plasmonic pressure sensor with Silicon-Insulator-Silicon waveguide configuration

This article introduces a novel Complementary Metal Oxide Semiconductor (CMOS) compatible plasmonic optical pressure sensor featuring a Silicon-Insulator-Silicon (SIS) waveguide configuration. The sensor design incorporates a railtrack resonator coupled to a straight waveguide with gratings, further enhanced by embedding silicon nanorods into the waveguide and resonator cavity. Finite element method (FEM) was used to perform numerical investigation and evaluate the performance of our sensor. The proposed sensor exhibits a pressure sensitivity of 51.075 nm/MPa, surpassing that of previous silver-based sensors and showcasing the potential of silicon in plasmonic sensing applications. Moreover, this work represents the first instance of employing CMOS-compatible silicon for designing an optical pressure sensor, thereby bridging the gap between plasmonic optomechanical sensors and nanoelectronics while circumventing the compatibility issues typically associated with metals in standard CMOS fabrication processes. By leveraging silicon as a plasmonic material, we have effectively addressed the constraints, such as lack of tunability and poor optical and thermal stability, that are suffered by traditional metal-based sensors. Moreover, building upon the recent advancements in silicon photonics, the need for setting up new manufacturing infrastructures for novel materials, such as transition metal nitrides, is overcome by the use of silicon due to the well-established fabrication facility of the silicon industry. The sensor's versatility and impact across diverse domains are highlighted by its potential applications, including gas leakage detection, flow rate measurement and refractive index sensing for early diagnosis of organ rejection post-transplantation.