Fig. 1. Schematic of sensing structure

Fig. 2. Response of SPR resonance peak to refractive index. (a) Transmission spectra; (b) central wavelength shift

Fig. 3. Sensor fabrication process

Fig. 4. Response of refractive index. (a) Reference spectrum; (b) transmission spectrun at refractive index of 1.33

Fig. 5. Temperature test device

Fig. 6. Response of temperature. (a) Transmission spectra; (b) sensitivity of temperature

Fig. 7. Stability and cross-sensitivity test. (a) Stability test; (b) sensitivity at different relative humidity values

Fig. 8. Relative humidity test device

Fig. 9. Humidity response of different samples. (a)(b) Sample s-1; (c)(d) sample s-2; (e)(f) sample s-3

Fig. 10. Stability and cross-sensitivity testing. (a) Stability test of sample-2; (b) sensitivity at different temperatures