激光共聚焦近红外荧光扫描系统光学设计

Optical design of near infrared fluorescence confocal laser scanning system

为了实现对近红外荧光的高分辨率扫描,设计了工作在近红外光谱区的激光共聚焦光学系统。采用结构简单的凹凸双透镜物镜实现了照明光路和发射光路的设计,并采用Zemax软件进行了光学设计和仿真。实验表明:照明光路的聚焦弥散斑小于1μm,照明针孔处的聚焦光斑小于40μm,满足照明针孔的尺寸要求;发射针孔处的聚焦光斑小于10μm,满足探测针孔尺寸要求;同时照明光路和发射光路的MTF曲线的截止频率都分别满足其衍射极限分辨率的要求,照明光路在全视场空间分辨率420lp/mm处MTF>0.08,发射光路在全视场空间频率400lp/mm处MTF>0.07。

In order to realize the high resolution scanning for near infrared fluorescence,a laser scanning confocal optical system was designed which worked in the near infrared region.The lighting lens,and emission lens were realized based on simple concave lens and convex lens.The software Zemax was used for the optical design and simulation.Simulation results shows that the focal spot's size of lighting lens is less than 1μm,and the focal spot's size is less than40μm at the lighting pinhole position,which meets the lighting pinhole's requirement.The focal spot's size is less than 10μm at the emission pinhole position,which meets the emission pinhole's requirement.In addition,the cutoff frequency of the lighting lens and emission lens meets the diffraction limit resolution requirement respectively.Therefore,it has high optical transmission efficiency.