Optik 156 (2018) 384–390 Contents lists available at ScienceDirect Optik j o ur nal ho me pa ge: www.elsevier.de/ijleo Full length article Numerical analysis of graphene coated surface plasmon resonance biosensors for biomedical applications M. Saifur Rahman a,∗ , Khaleda Akter Rikta a , Labid Bin Bashar b , M.S. Anower a a Department of Electrical and Electronic Engineering, Rajshahi University of Engineering & Technology, Rajshahi, 6204, Bangladesh b Department of Mechatronics Engineering„ Rajshahi University of Engineering & Technology, Rajshahi-6204, Bangladesh a r t i c l e i n f o Article history: Received 14 September 2017 Accepted 8 November 2017 Keywords: Biosensor Surface plasmon resonance Sensitivity Graphene a b s t r a c t This paper describes the effect of adding graphene layers in prism and planar waveg- uide based surface plasmon resonance biosensors using angular interrogation mode. The proposed sensors are designed based on graphene material as biomolecular recognition ele- ments (BRE) and the sharp SPR curve of gold (Au). Our calculations show that the proposed graphene in prism and planar waveguide based SPR biosensors have 1 + 0.40 L and 1+0.45 L; (where L is the number of graphene layers) times more sensitivity than the conventional SPR biosensor respectively. The enhanced sensitivity is due to increased SPR angle change about 40 L% and 45 L% by adding graphene layer and using the optical property of graphene. We also investigate the performance of proposed biosensors in terms of sensitivity using graphene sublayers. The compact size, prism and planar waveguide based design, and very high sensitive- these characteristics are expected to make these biosensors preferred choice for biomedical applications, as compared to other contemporary biosensors. © 2017 Elsevier GmbH. All rights reserved. 1. Introduction In modern days, vast research area has been founded centering surface plasmon resonance (SPR) based biosensor making many researchers enthusiastic due to its fast growing field of applications such as analysis of biochemical substances like protein, DNA, different enzymes and so on. The SPR technique has gained uniqueness for its real time sensing and level free detection [1]. In case of SPR based biosensors, surface plasmon wave (SPW), a schematic representation of an electron density wave propagation or plasma oscillation is generated along metal-dielectric interface with resonant frequency simulated by incident light. That means, when light rays incident on the interface and matches with wave vector of surface plasmon (SP), resonance occurs at the surface [2]. Today, different types of SPR based biosensor has been investigated and developed on the basis of dielectric medium and types of metal layers coated over it. Among them prism-Au based SPR biosensor is conveniently used [1,3]. A p-polarized light falls into glass prism and reflected from gold coated prism facet [4]. In this case, deviation of reflected angle helps to detect the nature of biochemical substance got to keep on biosensor. But this type of biosensor would face complexity monitoring remote and distant species. Besides, large systems with costly projects can only suit this type of SPR based biosensor. Therefore it would be only suitable working at laboratory [4]. ∗ Corresponding author. E-mail addresses: saifurrahman121042@gmail.com (M. Saifur Rahman), krikta.eee.ruet@gmail.com (K.A. Rikta), labid.bashar@gmail.com (L.B. Bashar), md.shamimanower@yahoo.com (M.S. Anower). https://doi.org/10.1016/j.ijleo.2017.11.057 0030-4026/© 2017 Elsevier GmbH. All rights reserved.