Refractive Index Sensor Based on a 1D Photonic Crystal in a Microfluidic Channel

Abstract: A refractive index sensor has been fabricated in silicon oxynitride by standard UV lithography and dry etching processes. The refractive index sensor consists of a 1D photonic crystal (PhC) embedded in a microfluidic channel addressed by fiber-terminated planar waveguides. Experimental demonstrations performed with several ethanol solutions ranging from a purity of 96.00% (n = 1.36356) to 95.04% (n = 1.36377) yielded a sensitivity (ΔΔ Δn/ ) of 836 nm/RIU and a limit of detection (LOD)of 6 × 10 -5 RIU, which is, however, still one order of magnitude higher than the theoretical lower limit of the limit of detection 1.3 × 10 –6 RIU. Keywords: 1D photonic crystal; refractive index sensor; integrated waveguides; electrochromatography 1. Introduction In the previous decades, a lot of work has been done onthe miniaturization of chemical analysis systems in order to benefit from faster analysis times, reducereagent consumption and d possiblyto realize cheaper portable systemsThis has resulted in a. great increase in the availability of chemical analyses throughout societyH. owever, the detection part of the miniaturized analysis systems remains