基于双直角棱镜的光纤光度传感器

Photometric Sensor Based on Dual Rectangular Prisms with Optical Fiber

设计了一个结构紧凑、灵敏度可调的双直角棱镜反射室,并结合光纤传感技术用于溶液光度分析,通过测量吸光度确定水中痕量物质的浓度和消光系数。带尾纤的自聚焦准直透镜发射的检测光束在反射室内往返4次,最后由接收光纤接收。论述了光度传感器的检测原理及棱镜反射室的设计方法,分析给出了棱镜室中光束的传输特性方程,以及单波长法测浓度和消光系数的测量方程,并通过实验进行了研究。结果表明,通过改变两棱镜底面间距,可调节光程,进而改变传感器灵敏度;该光度传感器的灵敏度为普通单程吸收池灵敏度的4倍,更加适合痕量物质的检测。

A light reflection chamber was introduced which contained two rectangular prisms. Due to the total reflection of prisms,the sensitivity of the chamber was enhanced by a factor of 4 with reference to the chamber without prisms. And by changing the distance of these two prisms, the chamber sensitivity can be adjusted. Based on the analyzed transmission equation of light beam in the prism chamber, we proposed a photometric sensor using this chamber in conjunction with optical fiber. Applying this sensor to measuring the absorbance,we can determine trace substance concentration in water and the total interaction coefficient, the meas- urement equations of which were put forward by using single - wavelength method. The design of the sensor is simple and compact, and its suitable for detecting trace substance.