Dual-Mode High-Q Multiphysics Sensor Based on the Evanescent Wave in the InSb Photonic Crystals

In this article, a dual-mode multiphysical quantity sensor is designed based on the indium antimonide (InSb) photonic crystals (PCs), which are using the evanescent wave principle. The sensor is mainly composed of InSb and three isotropic dielectrics, one layer of which is the dielectric to be measured. By adjusting the magnetic field strength, the operation modes of the structure can be controlled to switch between the transmittance and interference absorption cases. In a transmittance mode, the dielectric to be measured is set to the air layer, and sensing of magnetic field strength, thermodynamic temperature, and incident angle can be achieved. While for the interference absorption mode, the refractive index and the thickness of the dielectric to be measured can be obtained. It is worth mentioning that the linear range for sensing the dielectric thickness and refractive index in this mode is theoretically infinite based on the principle of interferometric light. In addition to the benefits of the introduction of the evanescent wave structure, the sensor has extremely high-quality factors (
${Q}$
) for the measurement of various physical quantities. Thus, this design is likely to reveal great potential in the field of physical measurements.