Zhou, G.; Li, L.; Zhou, Y.; Chen, X. High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector. Sensors2024, 24, 2050.
Zhou, G.; Li, L.; Zhou, Y.; Chen, X. High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector. Sensors 2024, 24, 2050.
Zhou, G.; Li, L.; Zhou, Y.; Chen, X. High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector. Sensors2024, 24, 2050.
Zhou, G.; Li, L.; Zhou, Y.; Chen, X. High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector. Sensors 2024, 24, 2050.
Abstract
The refractive index of seawater is one of the essential parameters in ocean observation, so it is necessary to achieve high precision seawater refractive index measurement. In this paper, we propose a method for measuring the refractive index of seawater based on a Position Sensitive Detector (PSD). Theoretical model is established to depict the correlation between laser spot displacement and refractive index change, utilizing a combination of position sensitive detector and laser beam deflection principle. Based on this optical measurement method, a seawater refractive index measurement system was established. To effectively enhance the sensitivity of refractive index detection, a focusing lens was incorporated into the optical path of the measuring system, and simulations were conducted to investigate the impact of focal length on refractive index sensitivity. The calibration experiment of the measuring system was performed based on the relationship between refractive index of seawater and underwater pressure (depth). By measuring laser spot displacement at different depths, changes in displacement with respect to both refractive index and depth were determined. Experimental results demonstrate that the system exhibits a sensitivity of 9.9277×10−9RIU (refractive index unit), the refractive index deviation due to stability is calculated as ±7.545×10−9RIU. Thereby the feasibility of highly sensitive measurement of seawater refractive index is verified.
Keywords
refractive index; Position Sensitive Detector (PSD); optical measurement; depth
Subject
Physical Sciences, Optics and Photonics
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
