High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector
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 measurements. In this paper, we propose a method for measuring the refractive index of seawater, based on a position-sensitive detector (PS...
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MDPI AG
2024-03-01
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| Online Access: | https://www.mdpi.com/1424-8220/24/7/2050 |
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| author | Guanlong Zhou Liyan Li Yan Zhou Xinyu Chen |
| author_facet | Guanlong Zhou Liyan Li Yan Zhou Xinyu Chen |
| author_sort | Guanlong Zhou |
| collection | DOAJ |
| description | 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 measurements. In this paper, we propose a method for measuring the refractive index of seawater, based on a position-sensitive detector (PSD). A theoretical model was established to depict the correlation between laser spot displacement and refractive index change, utilizing a combination of a position-sensitive detector and laser beam deflection principles. 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 the 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. The experimental results demonstrate that the system exhibits a sensitivity of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>9.93</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">R</mi><mi mathvariant="normal">I</mi><mi mathvariant="normal">U</mi></mrow></semantics></math></inline-formula> (refractive index unit), and the refractive index deviation due to stability is calculated as <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>7.54</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">R</mi><mi mathvariant="normal">I</mi><mi mathvariant="normal">U</mi></mrow></semantics></math></inline-formula>. Therefore, the feasibility of this highly sensitive measurement of seawater refractive index is verified. Since the sensitivity of the refractive index measurement of this measurement system is higher than the refractive index change caused by the wake of underwater vehicles, it can also be used in various applications for underwater vehicle wake measurement, as well as seawater refractive index measurement, such as the motion state monitoring of underwater navigation targets such as AUVs and ROVs. |
| first_indexed | 2024-04-24T10:36:00Z |
| format | Article |
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| language | English |
| last_indexed | 2024-04-24T10:36:00Z |
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| spelling | doaj.art-b90722d84e9547c192fdf0236d2044202024-04-12T13:26:05ZengMDPI AGSensors1424-82202024-03-01247205010.3390/s24072050High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive DetectorGuanlong Zhou0Liyan Li1Yan Zhou2Xinyu Chen3School of Physics, Changchun University of Science and Technology, Changchun 130022, ChinaOptoelectronics System Laboratory, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, ChinaOptoelectronics System Laboratory, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, ChinaSchool of Physics, Changchun University of Science and Technology, Changchun 130022, ChinaThe refractive index of seawater is one of the essential parameters in ocean observation, so it is necessary to achieve high-precision seawater refractive index measurements. In this paper, we propose a method for measuring the refractive index of seawater, based on a position-sensitive detector (PSD). A theoretical model was established to depict the correlation between laser spot displacement and refractive index change, utilizing a combination of a position-sensitive detector and laser beam deflection principles. 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 the 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. The experimental results demonstrate that the system exhibits a sensitivity of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>9.93</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">R</mi><mi mathvariant="normal">I</mi><mi mathvariant="normal">U</mi></mrow></semantics></math></inline-formula> (refractive index unit), and the refractive index deviation due to stability is calculated as <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>7.54</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>9</mn></mrow></msup><mtext> </mtext><mi mathvariant="normal">R</mi><mi mathvariant="normal">I</mi><mi mathvariant="normal">U</mi></mrow></semantics></math></inline-formula>. Therefore, the feasibility of this highly sensitive measurement of seawater refractive index is verified. Since the sensitivity of the refractive index measurement of this measurement system is higher than the refractive index change caused by the wake of underwater vehicles, it can also be used in various applications for underwater vehicle wake measurement, as well as seawater refractive index measurement, such as the motion state monitoring of underwater navigation targets such as AUVs and ROVs.https://www.mdpi.com/1424-8220/24/7/2050refractive indexposition-sensitive detector (PSD)optical measurementdepth |
| spellingShingle | Guanlong Zhou Liyan Li Yan Zhou Xinyu Chen High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector Sensors refractive index position-sensitive detector (PSD) optical measurement depth |
| title | High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector |
| title_full | High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector |
| title_fullStr | High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector |
| title_full_unstemmed | High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector |
| title_short | High-Sensitivity Seawater Refraction Index Optical Measurement Sensor Based on a Position-Sensitive Detector |
| title_sort | high sensitivity seawater refraction index optical measurement sensor based on a position sensitive detector |
| topic | refractive index position-sensitive detector (PSD) optical measurement depth |
| url | https://www.mdpi.com/1424-8220/24/7/2050 |
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