Extremely high signal-to-noise ratio surface plasmon resonance sensor using a monolithic prism sensor chip

A high signal-to-noise ratio in a surface plasmon resonance (SPR) sensor was achieved using a monolithic prism sensor chip. To achieve this, a multi-differential detection technique that uses a wavelength-stabilized laser diode with optical feedback was developed. To achieve easy exchange of the sensor chip and high accuracy of measurement, the monolithic prism sensor chip was fabricated from plastic with low photo-elasticity by the injection molding method. The resolution of our sensor system was estimated to be ‹10-7 refractive index unit. The potential of the developed sensor is very high for biosensing.