Measurement of chlorophyll in water based on Y-type fiber

In this paper, a novel chlorophyll measurement system based on Y-type fiber is designed, and the chlorophyll value is obtained according to the intensity ratio of laser fluorescence-Raman signal produced by laser incident into water. In the system, a 405nm semiconductor laser is used as the light source. The laser is coupled into the delivering port of Y-type fiber and then transmitted into water. The generated scattered light, water Raman light and corresponding fluorescence are received and transmitted into spectrometer through the detecting port of Y-type fiber, and the chlorophyll can be obtained by analyzing the laser fluorescence-Raman ratio of water spectra. In experiment, we detect the chlorophyll standard solutions under a range of concentrations, and establish the correlation between chlorophyll concentration and fluorescence-Raman ratio (r²=0.98). In addition, the chlorophyll of natural water sample is measured with laser spectroscopy, the results of which are consistent with chlorophyll values obtained by traditional spectrophotometry. The experimental results prove that the chlorophyll detection method proposed in this paper has the advantages of high sensitivity, high precision, high detection speed and simplicity, which can be widely used in various water areas for real-time chlorophyll detection.