Fig. 1. Schematic diagram of SP excitation by objective-coupled Kretschmann configuration

Fig. 2. Simulated relationship curves between refractive index and SPR wavelength when changing excitation angles. (a) SPR reflectance spectra of different dielectric refractive index for excitation angle of 54.2524°; (b) relationship between resonance wavelength and refractive index of dielectric under different excitation angles (fitting line represents the maximum sensitivity and detection range); (c) normalized reflectance varying with angle under different resonance wavelengths and refractive indexes

Fig. 3. Diagram of optical path and spectrum of white light source within the range of 500-850 nm. (a) Experimental setup of wavelength and angle co-modulated SPR sensor; (b) spectrum of white light source within the range of 500-850 nm

Fig. 4. Relationship between excitation angle and resonance wavelength. (a) SPR reflectance spectra for different excitation angles when dielectric is air; (b) curve of resonance wavelength varying with excitation angle (the solid curve represents the binomial fitting)

Fig. 5. Relationship between refractive index and resonance wavelength with fixed excitation angle. (a) SPR reflectance spectra of glucose solutions with different concentrations for fixed excitation angle of 55.25°; (b) curve of resonance wavelength varying with refractive index (the solid line represents the linear fitting result)

Fig. 6. Relationship between refractive index and resonance wavelength with wavelength and angle co-modulation. (a) SPR reflectance spectra of glucose solutions with different concentrations for different excitation angles; (b) curve of resonance wavelength varying with refractive index under different excitation angles (the solid line represents the linear fitting result)

Table 1. Relationship among refractive index, excitation angle, and resonance wavelength under maximal detection sensitivity