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Authors: T. Claes, W. Bogaerts, P. Bienstman
Title: Vernier-cascade silicon photonic label-free biosensor with very large sensitivity and low-cost interrogation
Format: International Conference Proceedings
Publication date: 8/2011
Journal/Conference/Book: Proceedings of SPIE 8099
Location: San Diego, United States
DOI: 10.1117/12.891818
Citations: 8 ( - last update: 7/7/2024)
2 (OpenCitations - last update: 3/5/2024)
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Recently, cheap silicon-on-insulator label-free ring resonator biosensors have been demonstrated that allow fast and accurate quantitative detection of biologically relevant molecules for applications in medical diagnostics and drug development. However, a further improvement of their detection limit is limited by their small sensitivity and an expensive tunable laser is typically required to resolve the sharp resonances for wavelength interrogation. Therefore, we experimentally investigated the use of a Vernier-cascade sensor that achieves a sensitivity (thousands of nm/RIU) that is an order of magnitude larger than that of a ring resonator sensor (approx. 100 nm/RIU), while still maintaining sharp spectral features that allow precise monitoring of spectral shifts with data-fitting. Moreover we prove that it's also possible to accurately interrogate the sensor with a low-cost broadband light source by integrating it with an arrayed waveguide grating spectral filter that divides the sensor's transmission spectrum in multiple wavelength channels and transmits them to spatially separated output ports. Experiments show that this sensor can monitor refractive index changes of watery solutions in real-time with a detection limit (1.6 • 10-5 RIU) competitive with more expensive interrogation schemes, indicating its applicability in low-cost label-free biosensing.

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