Improved system resolutions for surface plasmon resonance (SPR) will enable applications in more fields. This paper shows theoretically that the resolution of SPR with angular modulation is not only improved with increased sensitivity, but also with a narrower half-peak width. The resolutions with Au, Ag and Au-Ag chips show that the resolution of the Au-Ag chip is higher than that of the Au chip. Thus, the system resolution can be improved by using the Au-Ag chip. Measurements of the resolution of Au and Au-Ag chips using NaCl solutions with different mass fractions show that the Au and Au-Ag chip resolutions are 5.2×10-6 and 3.9×10-6 RIU (refractive index unit). Thus, the Au-Ag chip resolution is 1.4 times higher than the Au chip, similar to the theoretical result being 1.6 times higher.
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