| In this paper,a one-dimensional magnetic photonic crystal is combined with a PT(Parity-Time)symmetrical structure to achieve a unique non-reciprocal transmission of the structure.It is found that the structure has a unique sensing mechanism.So,a new theoretical model of a photonic crystal sensor is proposed.The model is different from the traditional sensing mechanism,to a certain extent,it can effectively improve the performance of optical sensors.The thesis firstly introduces the theoretical research method of PT symmetrical structure,and proposes a theoretical model based on non-reciprocal transmission of PT symmetrical structure.This model combines PT symmetrical structure with magneto-optical material,analyzes the influence of different parameters on the structure transmission characteristics,and realizes the non-reciprocal transmission of the structure.In addition,different magneto-optical materials can be selected,and the parameters of the modulation structure control the transmission performance of the structure.By adjusting the magnitude of the external bias magnetic field,the frequency band of spectral transmission characteristics can be changed,the structure can be operated in a larger frequency range,and the required transmission characteristics can be achieved in a specific frequency band,thereby expanding the application range of the structure.Based on the magnetic material and the PT symmetrical structure,a magnetic field sensor based on the PT symmetrical structure is proposed,and the sensor's sensing mechanism,sensing range,and sensitivity are analyzed.The PT symmetrical structure with magnetic resonator has a unique band edge mode,and the change of the bias magnetic field makes the magnetic permeability tensor of the gyromagnetic material change,which further changes the position of the structure band edge mode.The edge position of the transmission spectrum of the detection structure detects the external magnetic field and realizes magnetic field sensing.The sensitivity range of the sensor is expanded to 240nm/Oe–2.435×10~4nm/Oe.Finally,the paper investigates the properties of the PT symmetrical microcavity structure.Combing with electro-optic materials to design a wide range electric field sensor.Adjusting the quantum dot doping in the PT symmetrical structure can change the sensitivity of the electric field sensor.Due to the amplification effect of the PT symmetry on the defect mode,it is extremely advantageous for scanning the change of the peak value and position of the defect mode.Therefore,the designed electric field sensor has the characteristics of safety,reliability and wide measurement range.The research in this paper not only opens up new ideas for improving the performance of optical devices,but also proposes a new type of photonic crystal sensor implementation mechanism,which has reference value for the realization of optical sensors. |
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