A High‐Sensitivity Refractive Index Sensor Based on an External Gold Coating of a Square‐Lattice Photonic Crystal Fiber. Issue 6 (28th April 2021)

• Record Type: Journal Article
• Authors: Wang, Yujun; Li, Shuguang; Wang, Mingyue
• Is Part Of: Physica status solidi. Volume 15:Issue 6(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-04-28
• Subjects: full vector finite element method -- high sensitivity -- photonic crystal fibers -- refractive index sensors; Solid state physics -- Periodicals; 530.4105
• DOI: 10.1002/pssr.202100001
• Languages: English
• ISSNs: 1862-6254

Abstract

Abstract : A high‐sensitivity square‐lattice photonic crystal fiber (PCF) refractive index (RI) sensor based on an external gold coating is proposed. This design eliminates the limitations of selective coating and liquid penetration in the micrometer holes, and avoids the side polishing of D‐type fibers. The effects of air hole diameter and gold film thickness on the sensing performance are studied in detail using the full vector finite element method (FV‐FEM). In addition, the sensing performance of the gold‐coated PCF under the optimized parameters is compared with that of PCF with the same air hole diameter and a gold grating. The results show that the proposed PCF has a higher structural tolerance to the air hole diameter, which improves the manufacturing feasibility. Moreover, the gold‐coated PCF has a maximum sensitivity of 31 000 nm RIU −1 and a resolution of 3.23 × 10 −6 RIU in the RI measurement range of 1.34–1.49. The maximum sensitivity of the gold‐grating PCF with lower loss is 30 000 nm RIU −1 in the RI detection range of 1.38–1.46, and the resolution is 3.33 × 10 −6 RIU. Low loss is beneficial for extending the length of the fiber, which is convenient for practical implementation. Thus, it has potential applications in biomolecular and biochemical analysis. Abstract : A high‐sensitivity square‐lattice photonic crystal fiber refractive index (RI) sensor with external gold coating is proposed. The maximum sensitivity of the PCF sensor with gold coating and gold‐grating can reach 31 000 and 30 000 nm RIU −1 in the RI range of 1.34–1.49 and 1.38–1.46, respectively. Meanwhile, it has a high structural tolerance to the variation of the air hole diameter.