近红外二区宽谱段光学成像系统设计

Design of NIR-II imaging system with wide spectrum

针对近红外二区活体小动物荧光成像需求,解决宽谱段内多种波长同时复用问题,研究成像镜组的光学设计方法。以像差校正为设计出发点通过像差曲线的判读逐步迭代镜组结构;通过合理的光焦度分配加大后工作距离;通过玻璃材料选择优化兼顾宽谱段色差控制与能量透过率。最终获得光学系统焦距为40mm的光学结构,在工作距离范围内(200~600 mm),近红外二区波段(0.9~2.3μm)均可保证MTF>0.6@34 lp/mm,RMS点斑尺寸小于像元尺寸15μm,全视场畸变小于1%。经分辨率靶标实拍测试能够达到50μm的分辨能力。该光学设计方案提供了一种全玻璃球面透镜的解决方案,可以满足低探测阈值高质量活体小动物荧光成像需求。

To address the demand for in vivo small animal fluorescence imaging in the near-infrared II(NIR-II)window,as well as solve the problem of simultaneous reuse of multiple wavelengths within a wide spectral range.This study took the perspective of aberration correction and designed an optical system by iteratively refining the lens group structure based on aberration curves.The working distance was increased through reasonable focal length distribution,and the glass material selection was optimized to balance chromatic aberration control and energy transmittance within the wide spectral range.The final optical structure ended up with a focal length of 40 mm,capable of ensuring MTF>0.6@34 lp/mm for the NIR-II spectral band(0.9~2.3μm)within the working distance range(200~600 mm),with RMS spot size smaller than the pixel size(15μm)and distortion less than 1%across the entire field of view.Realshot tests with resolution targets demonstrate a resolution capability of 50μm.This optical design provides a solution based on all-glass spherical lenses capable of meeting the requirements for high-quality,low detection threshold in vivo small animal fluorescence imaging in the NIR-II window.