Data analysis of surface plasmon resonance biosensor based on phase detection

Phase interrogation has the highest resolution in all surface plasmon resonance (SPR) detection methods; its resolution is highly dependent on data acquisition and analysis, including photoelectric conversion, ADC and algorithm. This article focuses on SPR micro-array biosensor; by using mathematic simulations, different resolutions are achieved by varying spatial sampling frequency, number of signal periods and bits of ADC. Meanwhile, algorithms including correlation, sinusoidal fitting, and Fourier transform process are studied. Results showed that, under ideal conditions, the minimum number of pixels needed for one sampling period is only 4 and one single period is enough for phase detection. Considering noise influence, resolution will be enhanced if more pixels are employed, but not remarkably. The resolution is mainly dependent on the bits of ADC, which is normally 0.15° for 8 bits ADC, 0.05° for 10 bits ADC and 0.01° for 12 bits ADC.