Photonic crystal slot waveguide for high sensitivity on-chip near-infrared optical absorption spectroscopy of xylene in water

Swapnajit Chakravarty; Wei-Cheng Lai; Xiaolong Wang; Che-Yun Lin; Ray T. Chen

doi:10.1117/12.883660

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12 May 2011 Photonic crystal slot waveguide for high sensitivity on-chip near-infrared optical absorption spectroscopy of xylene in water

Swapnajit Chakravarty, Wei-Cheng Lai, Xiaolong Wang, Che-Yun Lin, Ray T. Chen

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Proceedings Volume 8032, Next-Generation Spectroscopic Technologies IV; 80320N (2011) https://doi.org/10.1117/12.883660
Event: SPIE Defense, Security, and Sensing, 2011, Orlando, Florida, United States

Abstract

We experimentally demonstrate a 300μm long silicon photonic crystal slot waveguide for on-chip near-infrared absorption spectroscopy. Based on the Beer-Lambert absorption law, our device combines slow light in photonic crystal waveguide with high electric field intensity in low-index 75nm wide slot, which effectively increases the optical absorption path length of the analyte. We demonstrate near-infrared absorption spectroscopy of xylene in water, independent of near-infrared absorption signatures of water, with a hydrophobic PDMS sensing phase that extracts xylene from water. Xylene concentrations up to 100ppb (parts per billion) (86μg/L) in water were measured.

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Swapnajit Chakravarty, Wei-Cheng Lai, Xiaolong Wang, Che-Yun Lin, and Ray T. Chen "Photonic crystal slot waveguide for high sensitivity on-chip near-infrared optical absorption spectroscopy of xylene in water", Proc. SPIE 8032, Next-Generation Spectroscopic Technologies IV, 80320N (12 May 2011); https://doi.org/10.1117/12.883660

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