Affiliation:
1. Chinese Academy of Sciences
Abstract
The lab-on-fiber design philosophy is the foundation for creating high-performance integrated fiber sensors. Hence, this Letter proposes an ultra-compact Fabry–Perot interferometer (FPI) based on a laser-induced micro-cavity (LIMC-FPI) on a fiber end for measuring relative humidity. To our knowledge, this novel approach, named the fiber-end photopolymerization (FEP) technique, is applied to create a micro-cavity. Specifically, a pair of humidity-sensitive polymer pillars and a resin end cap obtained by FEP are integrated to generate the cavity. As the ambient humidity changes, the pillars lengthen or shorten, resulting in the spectral evolution of the LIMC-FPI. A typical humidity sensitivity of 0.18 nm/%RH is obtained experimentally. For monitoring the human breathing process, the LIMC-FPI is responsive in the breathing frequency range of 0.2 to 0.5 Hz, allowing a response and recovery time of less than 0.388 s and 1.171 s, respectively. This work introduces a fresh and cost-effective approach for developing lab-on-fiber concept-based sensors.
Funder
National Key Research and Development Program of China
the Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China (NSFC) and Chinese Academy of Sciences
the State Key Laboratory of Applied Optics
Fundamental Research Funds for the Central Universities
Subject
Atomic and Molecular Physics, and Optics