PROJECT TITLE :

Bulk Sensing Using a Long-Range Surface-Plasmon Dual-Output Mach–Zehnder Interferometer

ABSTRACT:

Optical bulk (refractometric) sensing of sample solutions is demonstrated using twin-output Mach–Zehnder interferometers built from long-range surface-plasmon polariton waveguides operating at a free-house wavelength of 1375 nm. The device of interest was made by embedding Au stripes in Cytop claddings and etching a fluidic channel through the high cladding of one arm of the interferometer to expose the Au stripe. Bulk sensing was dole out by flowing sequentially a series of solutions of various refractive index through the microfluidic channel. The optical powers of the 2 outputs responded sinusoidally and were complimentary, as expected in theory. Three detection schemes aiming at improving the detection limit are analyzed showing that the device edges from a 2× larger dynamic range, and has the power to suppress common perturbations, relative to one output. A detection limit of ∼4 × 10−half-dozen RIU is demonstrated, that will be additional improved by lengthening the sensing channel. The device is promising for application as a biosensor.