Fig. 1. Diagram of SHF under pressure

Fig. 2. 3D view of birefringence as a function of pressure

Fig. 3. Birefringence and pressure change relationship

Fig. 4. SHF birefringence measurement device diagram

Fig. 5. Interference spectrum without significant movement

Fig. 6. Interference spectrum when the pressure direction is near the x-axis （shift to the right）

Fig. 7. Comparison chart between experimental results and simulation results