Glyphosate And Mercury Trace Detection Based On Symmetric Metal-cladding Waveguide

Symmetric Metal-Cladding Optical Waveguide(SMCW) plays a more and more important role in the areas of integrated optics, sensor, and the thickness measurement of ultra-thin films because of its lightness, convenience and high sensitivity. SMCW consists of coating of mental clad, guiding layer and mental film substrate from top to bottom. Sensor generally treats the need-to-be measured materials as the guiding layer of SMCW and makes them be in the oscillating field to increase the penetration depth of exploration. At the same time, the guiding layer could reach submillimeter scale and SMCW could stimulate ultrahigh-order modes which show high sensitivity to the refractive index, thickness of guiding layer and wastage changes of waveguide.The movement of absorption peak index of Attenuated Total Reflection is related with the loss of waveguide intrinsic and radiation. This thesis conducts simulation of theory and experiment based on high sensitivity of SMCW to the loss with some tests of toxic substances. First, conducting specific color reaction to these toxic substances with different concentrations; and then changing waveguide intrinsic loss by incoming laser with complement wave length to the signified color in order to observe the movement of absorption peak index of Attenuated Total Reflection.Through the above methods, conducting related experiment with glyphosate, it shows us: the concentration test of glyphosate could reach under 1.4nmol/L. The shorter test time could be used for quick and effective glyphosate test to raise working efficiency. The amount of tested samples is only microlitre level to avoid the problem that couldn’t reach the testing standard owing to the shortage of it. Only if finding the suitable colour reagents and incoming laser, the measure could be applied to test other toxic substances, such as mercury and arsenic etc, which are harmful to environment and human body.According to the advantages of toxic substances test of SMCW, for example, low cost and limit of detection, short time and less amount of samples, it could be applied to test the majority toxic substances and provide a new method for environment monitoring and food safety. Therefore, it is a of great significance and practical study.