Actively manipulating the temperature characteristics of photonic spin Hall effect in quasi-PT symmetric structure

The photonic spin Hall effect (PSHE) manifests itself as the spin-dependent transverse shift, and has many applications including precise metrology and optical sensing. However, some common ways to control PSHE have the limitation of less flexible and convenient manipulation. We report here an approach to actively manipulate the temperature characteristics of the PSHE in the quasi-PT symmetric structure by means of tunable graphene conductivity under optical pumping. The underlying mechanism is the flexible control of exceptional point by influencing graphene conductivity. We find that the PSHE shift is significantly enhanced near the exceptional point, and the enhanced PSHE shift can be manipulated by temperature. Moreover, the variation of temperature causes the inversion of the sign of the PSHE shift, and the temperature properties of the shift change as the optical pumping power varies. Based on the tunable PSHE shift, we design a temperature sensor with tunable sensitivity by combining weak measurement amplification techniques.