激光多模式毛细管电泳检测器的光学设计及优化

The Optical Design and Optimization of Laser Based Multimode Detector for Capillary Electrophoresis

提出一种基于毛细管电泳的激光多模式检测器.为设计并优化其光路构型,进行了理论分析和数学推导,并采用Matlab仿真,得到光路中各参量优化取值范围.在热透镜通道,激发光束腰半径越小,则热透镜效应越强.而探测激光束腰半径、束腰与样品距离、样品与探测面距离三个参量综合决定检出信号强度;在回射干涉通道,聚焦透镜焦距应较短,它与毛细管距离对检测影响很大,而与激光器、与探测面的两距离对检测影响相对较小;热透镜效应对回射干涉检测影响不明显,如要严格消除,可将两通道错开一适当距离.

A laser-based multimode detector is introduced. To gain the optimal detection, the optical configuration is designed and optimized. Based on the theoretical analysis, mathematical deduction and Matlab simulation, the optimum numerical range of the parameters of the optical configuration are obtained. In the thermal lens detection mode, generally, smaller waist radius induces stronger the thermal lens effect,on the other hand,the waist radius of the probe beam, the distance between the waist and the sample and the distance between the waist and the detecting plane synthetically determine the intensity of the acquired signal. In the retroreflected detection mode, the focus length of the focusing lens has to be short enough,and the distance between the lens and the capillary, which has to be less, influences the detection a lot,while the lens has to be far enough both from the laser source and the detection plane. Finally,the thermal lens impacts the retroreflected interference unapparently. To eliminate the influence strictly,a proper little distance to shift the two detecting channels can be adopted.