All-fiber surface-enhanced Raman scattering detection system combining an integrated microfluidic chip and micro-lensed fiber.

It is a challenge to perform simple and rapid detection of substances due to their complex structure. Biochemical molecules play a vital role in human health and environmental testing. Surface-enhanced Raman scattering (SERS) detection has the characteristics of strong specificity and real-time performance. At present, most SERS systems are expensive and not portable. Here, we demonstrate a SERS detection system with all-fiber connection, combined with a microfluidic chip and micro-lenses. Compared with the conventional SERS system that uses the spatial optical path, the devices in our system are connected by optical fibers, making the system more stable and operable. Besides, the microfluidic chips are introduced to further improve the system integration and stability. Owing to the micro-lensed fiber probe, the detected Raman signal intensity is increased by 2-3 times. We anticipate that the presented work will lead toward a rapid and portable SERS system and corresponding detection system. It also lays the foundation for real-time recognition in various complex environments in the design of a future optical fiber system.