Fig. 1. SPR sensing structure

Fig. 2. Flow chart of phase unwrapping

Fig. 3. Curves of phase difference to incident angle for different gold film thicknesses. (a) Calculation results using the argument function; (b) calculation results using the unwrapping function

Fig. 4. Theoretical curve of phase difference as a function of gold film thickness. (a) Calculation results of phase difference for a 49.6 nm gold film; (b) relation curve between maximum phase difference and thickness variation

Fig. 5. Relation between optimal gold film thickness and incident light wavelength

Fig. 6. SPR phase detection system based on MZI

Fig. 7. Flowchart for phase difference calculation

Fig. 8. Experimental measurements and theoretical calculation of phase difference-angle relationships for gold films of different thicknesses. (a) 36.58 nm gold film; (b) 45.43 nm gold film; (c) 62.86 nm gold film