Development of a Surface Plasmon Resonance Sensor using 2D Materials, Including Graphene and Black Phosphorus, for Measuring Water Pressure
摘要
Understanding how the refractive index of water changes with wavelength under different physical and chemical conditions, such as temperature or pressure, is crucial for describing the behavior of light as it travels through, reflects from, and is absorbed by water. The refractive index can act as an in situ indicator of various physical properties of liquids, such as density and pressure. Research has highlighted the influence of pressure on the refractive index at specific visible wavelengths, emphasizing the need for further exploration of these relationships. This research presents a sophisticated surface plasmon resonance (SPR) optical sensor that integrates 2D materials into a Kretschmann setup. The sensor is structured with multiple layers, including a BK7 prism, gold (Au), black phosphorus (BP), and graphene. Its performance was assessed through the finite difference time domain (FDTD) method, allowing for an in-depth analysis of crucial parameters like sensitivity. At a wavelength of 633 nm, the sensor achieved outstanding performance, with a sensitivity of 174.61 deg/RIU and a figure of merit (FOM) of 26.36 RIU−1, surpassing earlier designs. These results demonstrate the sensor’s capability to measure liquid pressure, including that of water, by detecting changes in optical properties associated with varying pressures. The study shows that variations in the refractive index of water can be observed at pressures exceeding 100 or 250 MPa. Operating pressures up to 250 MPa are required for various applications, such as waterjet cutting of thick and hard materials.