A GRATING-BASED PLASMON BIOSENSOR WITH HIGH RESOLUTION

We present an idea of grating-based plasmon biosensor utilizing phase detection to realize high resolution in finding a refractive index of a material put on the surface of a metal grating. Considering a trade-off between high resolution and experimental practicability, we show a table of recommended setup that covers a wide range of the index. Keeping the diffraction efficiency no less than 10-3 and assuming the resolution in phase detection to be 2.5x10-2 degrees, we estimate the resolution of the biosensor as 7.5x10-7 refractive index units. We also discuss the possible improvement to realize a predicted superior limit of resolution around 10-8.