540 Planar Near-Infrared Surface Plasmon Resonance Sensor with Grating Coupler and Si Prism
Details
We have developed a Si microfabrication based SPR (Surface Plasmon Resonance) sensor chip equipped with Si prisms and an optical grating for sensor miniaturization. The Si prism structure was used to introduce the Near-Infrared light (λ = 1550 nm) to the sensing surface and generating the evanescent light there. Smooth prism slope was fabricated by utilizing (111) planes on the (100) plane of single crystalline Si wafer by anisotropic etching, giving small 200-μm prism array with 54.74° slope angle. We also used the optical grating with about 400-μm-pitch to manipulate an SPR dip position so as to increase the design freedom of the optical path within the sensor. SPR measurements with several specimens confirmed that the combination of Si prisms and the optical grating successfully worked to excite Surface Plasmon so that the sensor's validity as a refractive index sensor was also confirmed. Since this sensor is compatible with a Si microfabrication technology, further integration of optical parts, fluidic components and miniaturization of SPR sensor becomes possible, which is necessary for the application of an SPR sensor toward an environmental sensor.
