当前土壤重金属污染严重, 设计手持式土壤重金属现场、在线探测设备十分必要。系统发射光路采用会聚透镜将激光光束会聚并作用到样品; 收集光路采用抛物面镜和分离透镜组将等离子体光谱信号耦合进入光纤; 瞄准光路采用抛物面镜、反射镜和胶合透镜组将待测物点成像到毛玻璃上。激光光束经透镜会聚后作用到样品上的光斑尺寸合适; 等离子体光谱信号耦合至光纤的效率高, 耦合光束数值孔径满足选用光纤的要求; 瞄准系统对待测点成像清晰; 整个光学系统长、宽、高分别小于30、10、25 cm, 结构紧凑、体积小、轻便易携带。设计结果表明, 系统适用于非接触式土壤重金属现场、在线探测应用。

Today, soil heavy metal pollution is serious. It’s necessary to design a handheld, field and in-situ soil heavy metal detector. A lens is used to focus the laser beam on the sample. A paraboloidal mirror and a separate lens group are used to collect the plasma optical signal into the optical fiber. A paraboloidal mirror and a gluing lens group are used to image the target point to the matglass. The size of the light spot on the sample is suitable; the coupling efficency of the light which is collected into the optical fiber is high and the numetical aperture of the light satisfies the requirement of the selected fiber; the target point is imaged clearly to the matglass; the length, width and height of the whole optical system are separately less than 30cm, 25cm and 10cm, and therefore the system is compact, small-sized and easy to carry. The result shows that the system is suitable for non-contact, field and in-situ soil heavy metal detection.