Magnetic field sensor based on one-dimensional binary photonic crystal

The work describes the study of a 1D photonic crystal to detect the magnetic fluid as a function of temperature and magnetic field. The structural dimensions are designed by incorporating alternating layers in a periodic way. Each layer is formed as a pair, in which a combination of two materials, PbS and air, is made with a thickness of 91 nm and 387 nm. Along with the structure, there is another mode called the defect mode, with a thickness of 277.5 nm, where the detecting magnetic fluid is injected. The overall PC structure is characterized by the transfer matrix method (TMM), whose results in the transmission spectrum as a function of wavelength are analyzed theoretically. In response to the magnetic fluid, the defect mode is generated and meets resonance at a particular wavelength. The change in shift for magnetic fluid gives the results for sensor performances. In particular, the proposed sensor is optimized by its structural perceptions, and its sensitivity is identified for both magnetic field and temperature through the absorption of magnetic fluid. The study of the temperature dependence of magnetic fluid is carried out at high temperatures up to 500 K. The sensitivity is calculated by noting the shift in defect mode for various incident angles, thicknesses, and temperatures. An increase in the angle of incidence improves both the sensitivity and FOM. The maximum sensitivity achieved, which depends on magnetic field and temperature, is 31.2 pm Oe-1 and 6.46 pm K-1, respectively, for a thickness of 305.25 nm at an angle of incidence of 50 degrees. A maximum FOM of 57.884 Oe-1 is also achieved at an incident angle of 50 degrees and a temperature 300 K. The work's findings suggest developing prospective photonic devices, and the proposed PC has dual sensor characteristics that may be tuned.