One-dimensional photonic crystal magnetic sensor design based on Bloch surface waves with high sensitivity and high figure of merit (FOM)

•A novel one-dimensional photonic crystal magnetic sensor with high sensitivity and a high figure of merit.•Detection of magnetic fields by detecting small changes in the refractive index of magnetic fluid.•Grating is used to realize the coupling of electromagnetic waves and BSW.•High figure of merit is obtained by introducing defective layers.