Research on Mercury Ion Sensor Based on Whispering Gallery Mode

Mercury ion (Hg
²⁺
) is a kind of heavy metal ion with strong harm and extensive pollution, so the accurate measurement of Hg
²⁺
has extremely important practical significance. Based on the principle of whispering gallery mode (WGM), this paper adopted the simplest microsphere cavity coupled tapered fiber structure to detect Hg
²⁺
. The surface of the microsphere cavity was functionalized, and the combination of Hg
²⁺
and sensitive materials led to the change of effective refraction, followed by the shift of resonant wavelength, so as to achieve the purpose of detecting the concentration of Hg
²⁺
. The experimental results show that when the Hg
²⁺
concentration is 19.80 μM, the dip has a redshift of ~22 pm. The feasibility of Hg
²⁺
measurement based on WGM is preliminarily verified by experiments, and a higher practical value can be achieved by further improving the sensitivity.