在飞秒激光随机扫描双光子显微成像系统中使用宽带二维声光偏转器扫描飞秒激光, 可以增大扫描角度至74 mrad, 增大双光子显微成像范围。但宽带二维声光偏转器在大角度扫描时引入的色散较大, 造成成像范围边缘的光斑严重畸变, 边缘光斑直径达2.3 μm, 影响边缘视场的成像质量。为了提高成像质量, 设计了一种新的色散补偿方法, 基于衍射透镜组成的开普勒望远系统, 可以同时补偿不同扫描角度的不同色散。经过色散补偿后成像边缘的光斑直径小于1 μm, 使系统获得大范围扫描成像的同时, 所有扫描角度的色散都能够得到很好的补偿, 在整个视场范围内光斑直径小于1 μm, 实现更均匀的荧光激发, 均匀成像。

In femtosecond laser random scanning two-photon microscopic imaging system, using a broadband two-dimensional acousto-optic deflector scanning femtosecond laser can increase scanning angle to 74 mrad, increasing two-photon microscopic imaging range. But broadband two-dimensional sound and light deflector has large dispersion in large angle scan, resulting in serious distortion of imaging edge and spot diameter of 2.3 μm. In order to improve image quality, a new dispersion compensation method is designed. Kepler’s telescope system based on diffraction lenses can compensate different dispersions of different scanning angles. After dispersion compensation, imaging edge of spot diameter is less than 1 μm, so that wide range of scanning imaging is obtained and dispersions of all scanning angle are well compensated. Spot diameter throughout entire field of view is less than 1 μm and more uniform fluorescence excitation and imaging are achieved.