Abstract

A novel optical sensor for ammonia concentration in water is demonstrated using up-conversion (UC) fluorescence intensity ratio (FIR). The sensor element consists of (i) an Er³⁺-Yb³⁺ co-doped tellurite glass microsphere integrated inside a section of suspended tri-core hollow fiber (STCHF) and (ii) the pH indicator phenol red. When 980 nm pump is coupled into the microsphere, the Er³⁺ ions produce green and red UC emissions. Exposure to ammonia results in a strong increase in the 560 nm absorption of the phenol red, which acts as a filter for the green emission, while the red emission is unaffected. A simple linear relation between the FIR and the ammonia aqueous concentration has been established.

In-fiber temperature sensor based on green up-conversion luminescence in an Er³⁺-Yb³⁺co-doped tellurite glass microsphere

Meng Zhang, Angzhen Li, Jibo Yu, Xiaosong Lu, Shunbin Wang, Elfed Lewis, Gerald Farrell, Libo Yuan, and Pengfei Wang
Opt. Lett. 44(13) 3214-3217 (2019)

Fabrication and calibration of Oxazine-based optic fiber sensor for detection of ammonia in water

Ahmed Hasnain Jalal, Jinsong Yu, and A. G. Agwu Nnanna
Appl. Opt. 51(17) 3768-3775 (2012)

High sensitivity sol-gel silica coated optical fiber sensor for detection of ammonia in water

Dejun Liu, Wei Han, Arun Kumar Mallik, Jinhui Yuan, Chongxiu Yu, Gerald Farrell, Yuliya Semenova, and Qiang Wu
Opt. Express 24(21) 24179-24187 (2016)

Fiber optic fluorescence temperature sensors using up-conversion from rare-earth polymer composites

Sandra Sánchez-Escobar and Juan Hernández-Cordero
Opt. Lett. 44(5) 1194-1197 (2019)

Study on optical properties and upconversion luminescence of Er³⁺/Yb³⁺ co-doped tellurite glass for highly sensitive temperature measuring

Jianfeng Tang, Maojun Sun, Yawen Huang, Jie Gou, Yu Zhang, Guannan Li, Yuan Li, Yuhong Man, and Jun Yang
Opt. Mater. Express 7(9) 3238-3250 (2017)