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On-Chip Real-Time Chemical Sensors Based on Water-Immersion-Objective Pumped Whispering-Gallery-Mode Microdisk Laser

Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education, Provincial Key Laboratory for Photonics Technology, Institute of Laser and Optoelectronics Technology, Fujian Normal University, Fuzhou 350007, China
Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China
Authors to whom correspondence should be addressed.
Nanomaterials 2019, 9(3), 479;
Received: 21 February 2019 / Revised: 19 March 2019 / Accepted: 19 March 2019 / Published: 24 March 2019
(This article belongs to the Special Issue Dynamics and Applications of Photon-Nanostructured Systems)
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Optical whispering-gallery-mode (WGM) microresonator-based sensors with high sensitivity and low detection limit down to single unlabeled biomolecules show high potential for disease diagnosis and clinical application. However, most WGM microresonator-based sensors, which are packed in a microfluidic cell, are a “closed” sensing configuration that prevents changing and sensing the surrounding liquid refractive index (RI) of the microresonator immediately. Here, we present an “open” sensing configuration in which the WGM microdisk laser is directly covered by a water droplet and pumped by a water-immersion-objective (WIO). This allows monitoring the chemical reaction progress in the water droplet by tracking the laser wavelength. A proof-of-concept demonstration of chemical sensor is performed by observing the process of salt dissolution in water and diffusion of two droplets with different RI. This WIO pumped sensing configuration provides a path towards an on-chip chemical sensor for studying chemical reaction kinetics in real time. View Full-Text
Keywords: whispering-gallery-mode (WGM); sensor; water-immersion-objective (WIO); microdisk; laser whispering-gallery-mode (WGM); sensor; water-immersion-objective (WIO); microdisk; laser

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Lu, Q.; Chen, X.; Fu, L.; Xie, S.; Wu, X. On-Chip Real-Time Chemical Sensors Based on Water-Immersion-Objective Pumped Whispering-Gallery-Mode Microdisk Laser. Nanomaterials 2019, 9, 479.

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