Abstract
PURPOSE: Kretschmann-configuration has been used as a subwavelength framework to detect tiny alterations of the refractive index of biomaterials. However, most of the theoretical assessment of such configuration is usually based on the plane wave excitation transfer matrix method (TMM) of prism-coupled to thin metal film supporting plasmonic modes. Accordingly, a better theoretical framework than the plane wave approximation is indispensable for reliable and accurate assessments and simulations. A reformulated form of the traditional FFT-BPM has been adapted to evaluate the performance and characteristics of surface plasmonic waveguide biosensor. METHOD: Surface plasmon mode is excited by a sub-wavelength narrow light beam. The highly confined optical energy of that plasmonic mode enables an efficient means to detect tiny variations in the composition of the analyte in contact with the metallic layer of the surface plasmon guide. The plasmonic guided power is detected thereafter electronically via an optical MOS capacitor. RESULTS: the guided plasmonic power has been used to assess the fundamental characteristics and performance of the sensor, namely the linearity, sensitivity, and figure of merit as well as the full width at half maximum (FWHM). CONCLUSION: The proposed sensor could be integrated to a wide class of angular measurement system (for instance goniometer) or via electronic detection of the optical plasmonic guided power. we claim that this work is worthy of being shared with researchers and developers interested in the experimentation and assessment of sensitive biosensors; especially in case when complicated and sophisticated analysis tools represent an unpleasant burden.