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

• Main Authors: Klaus B. Mogensen, Jörg P. Kutter, Niels Asger Mortensen, Pedro S. Nunes
• Format: Article
• Language: English
• Published: MDPI AG 2010-03-01
• Series: Sensors
• Subjects: 1D photonic crystal; refractive index sensor; integrated waveguides; electrochromatography
• Online Access: http://www.mdpi.com/1424-8220/10/3/2348/

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 (Δλ/Δn) of 836 nm/RIU and a limit of detection (LOD) of 6 x 10-5 RIU, which is, however, still one order of magnitude higher than the theoretical lower limit of the limit of detection 1.3 x 10–6 RIU.