A Highly Sensitive Refractometric Sensor Based on Cascaded SiN Microring Resonators

Sensors

Vanessa Zamora¹  Peter Lützow²  Martin Weiland² 

[1] Fraunhofer Institute for Telecommunications, Heinrich Hertz Institute, Einsteinufer 37, Berlin 10587, Germany;

关键词: microring resonators;    refractometric sensors;    Vernier effect;    silicon nitride;    integrated optical devices;   

DOI  :  10.3390/s131114601

来源: mdpi

【 摘 要 】

We investigate a highly sensitive optical sensor based on two cascaded microring resonators exploiting the Vernier effect. The architecture consists of two microrings with a slight difference in their free spectral ranges. This allows the generation of the Vernier effect for achieving ultra-high sensitivities. The sensor chip was fabricated using a silicon nitride platform and characterized with isopropanol/ethanol mixtures. A sensitivity of 0.95 nm/% was found for isopropanol concentrations in ethanol ranging from 0% to 10%. Furthermore, a collection of measurements was carried out using aqueous sodium chloride (NaCl) in solutions of different concentrations, confirming a high sensitivity of 10.3 nm/% and a bulk refractive index sensitivity of 6,317 nm/RIU. A limit of detection of 3.16 × 10⁻⁶ RIU was determined. These preliminary results show the potential features of cascaded silicon nitride microring resonators for real-time and free-label monitoring of biomolecules for a broad range of applications.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.