显微荧光光谱采集系统的设计与可行性分析

Design and Simulation of Micro-fluorescence Spectra Detection System

显微荧光光谱采集常使用价格高昂的增强电荷耦合器件(ICCD)作为光探测器,为了增强快速采集信号的能力并控制成本,围绕多通道阳极光电倍增管(PMT)线阵探测器的使用需求,设计了一种可见光波段工作的显微荧光光谱采集系统。包括激光激发、物镜聚焦和采集、荧光传输等结构,并最终耦合至光纤接收信号。通过显微物镜及荧光光学系统性能分析,以及结合线阵PMT探测器特性的信噪比分析计算,在激发光源使用波长360 nm,功率为20 mW的紫外激光时,激光光斑在3.4μm包围圆范围内包含80%以上的能量。采集范围超过5μm时可获取90%以上的荧光辐射能量。采集积分时间为0.2 ms时信噪比超过10,能够得到强度足够的信号,满足显微荧光光谱采集的需求。

In order to reduce the cost and enhance the ability to quickly collect signals,a falling down optical path spectra detecting system is designed around the use of multi-channel anode photomultiplier tube(PMT)to ob-tain micro-fluorescence spectra.Including laser excitation,objective lens focusing,fluorescence transmission and fi-ber coupling,the design and simulation of the system is presented.The simulation results are estimated through the optical performance and the digital analysis of the system,also the characteristics of the working PMT.The results show that,when the excitation power is a 20 mW ultraviolet laser(360 nm),the energy concentration of the sur-rounding circle exceeds 80%within 3.4μm.The acquisition power reaches 90%when the detection area outweighs 5μm.The signal to noise ratio(SNR)at a 0.2 ms collecting integration surpasses 10,which indicates a signal with sufficient intensity being obtained to meet the requirements of micro-fluorescence spectra acquisition.