Ultra-sensitive pressure sensing capabilities of defective one-dimensional photonic crystal

Present research work deals with the extremely sensitive pressure-sensing capabilities of defective one-dimensional photonic crystal structure (GaP/SiO₂)N/Al₂O₃/(GaP/SiO₂)N. The proposed structure is realized by putting a defective layer of material Al₂O₃ in the middle of a structure consisting of alternating layers of GaP and SiO₂. The transfer matrix method has been employed to examine the transmission characteristics of the proposed defective one-dimensional photonic crystal in addition to MATLAB software. An external application of the hydrostatic pressure on the proposed structure is responsible for the change in the position and intensity of defect mode inside the photonic band gap of the structure due to pressure-dependent refractive index properties of the materials being used in the design of the sructure. Additionally, the dependence of the transmission properties of the structure on other parameters like incident angle and defect layer thickness has also studied. The theoretical obtained numeric values of the quality factor and sensitivity are 17,870 and 72 nm/GPa respectively. These results are enough to support our claim that the present design can be used as an ultra-sensitive pressure sensor.