Design of a high figure of merit subwavelength grating based plasmonic sensor for detection of DNA hybridization

UA SPR biosensor based on a metallic subwavelength grating structure is studied for detection of DNA hybridization. Performance and dispersion curve characteristics of the sensor are investigated numerically for variations of the grating geometry parameters by finite element method (FEM) as a numerical method. The results of this investigation are used to design a high figure of merit (FOM) SPR sensor in near-infrared (NIR) wavelength of 984nm. Also, performance of the sensor in visible wavelength of 633 nm is studied and compared with the NIR one. This study shows that the performance changing with the grating geometry parameters can be elucidated well by evaluating the effects of those parameters especially fill factor (f.f.) on the dispersion curve. Numerical study results in obtaining a higher FOM for operating wavelengths in NIR range in contrary to visible wavelengths because a NIR wavelength can be adjusted as a band edge wavelength locating in the flattened part of the dispersion curve by selecting appropriate values of f.f. and grating thickness. (C) 2015 Elsevier GmbH. All rights reserved.