A Highly Sensitive SPR Refractive Index Sensor Based on Microfluidic Channel Assisted With Graphene-Ag Composite Nanowire

Abstract

A highly sensitive refractive index (RI) sensor based on a microfluidic channel (MFC) incorporated in a single-mode fiber (SMF), filled with Ag-graphene composite nanowire is presented and analyzed here. The sensing performance and the coupling properties of designed sensor are numerically analyzed by using a full vectorial finite element method (FEM) incorporating amplitude and wavelength interrogation techniques in the detection range varied from n <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sub> = 1.330-1.350. The maximum wavelength and amplitude sensitivity are obtained of 13700 nm/RIU and 1026 RIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , respectively. Here, the Ag-graphene composite nanowire can not only solve the problem of oxidation but also enhances the sensitivity of the sensor. In addition of high sensitivity, it also provides better performance than other sensing devices based on similar technologies such as Ag nanowire-filled sensors. Moreover, the influences of polishing depth (D), nanowire radius (r <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</sub> ), graphene layer (L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> ) and channel size (s) on the designed sensor, are also thoroughly investigated here. The present work can provide a base for designing a real-time, highly sensitivity, remote sensing, and distributed SPR based RI sensor.