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

摘要: Optical bulk (refractometric) sensing of sample solutions is demonstrated using dual-output Mach–Zehnder interferometers built from long-range surface-plasmon polariton waveguides operating at a free-space wavelength 1375 nm. The device interest was constructed by embedding Au stripes in Cytop claddings and etching fluidic channel through the top cladding one arm interferometer to expose stripe. Bulk carried out flowing sequentially series different refractive index microfluidic channel. optical powers two outputs responded sinusoidally were complimentary, as expected theory. Three detection schemes aiming improving limit are analyzed showing that benefits 2× larger dynamic range, has ability suppress common perturbations, relative single output. A ∼4 × 10−6 RIU demonstrated, which can be further improved lengthening promising for application biosensor.