Optical Bio-sensing with an Asymmetric Hybrid Plasmonic Mach-Zehnder Interferometer

Abstract

A silicon (Si) suspended metal strip loaded hybrid plasmonic waveguide is designed and optimized to obtain a high waveguide sensitivity for bio-sensing applications. The waveguide forms a horizontal slot which confines a high ∼59% power with the optimized design parameters. Any liquid refractometric changes can be detected by this waveguide and its quasi-TM waveguide sensitivity shows a very high value of >1. Finally, an asymmetric Mach-Zehnder interferometer (AMZI) is designed to detect a small refractometric change in terms of interferometric fringe shift. Our proposed design exhibits a high refractometric sensitivity of > 400 nm/RIU. The AMZI is then considered to use for an accurate detection of haemoglobin (Hb) concentration of human whole blood. This ex vivo detection process exhibits a promising device sensitivity of -781.05 pm/g/dl with a detection limit of 1.3 mg/dl which makes this device useful for a precise detection of anaemic status of a patient.