本文提出利用离轴抛物镜共焦中继系统来改善双光子成像视场边缘像质变差的问题, 进而提升双光子成像视场。不同于传统的双胶合透镜扫描中继系统, 离轴抛物镜共焦扫描中继系统由一对离轴抛物镜构成, 扫描振镜位于抛物面镜焦点处。仿真和试验结果均显示, 该系统能有效优化视场边缘的像散、场曲和畸变情况, 提高成像质量。利用该扫描系统, 我们实现了视场为2.4 mm×2.4 mm, 横向分辨率为1 μm的大视场双光子显微成像, 能清晰分辨小鼠大脑切片中的神经轴突结构。

We propose an off-axis parabolic mirror (OAPM) afocal scanning system which can improve the image quality in the marginal area of two-photon microscopy. Compared with the traditional double lenses afocal scanning system, the OAPM afocal scanning system consists of a pair of parabolic mirrors, and a galvo scanner is located at one of the foci of the parabolic mirror. Both the simulation and experiment results show that the OAPM afocal scanning system can significantly reduce the astigmatism, the field curvature and the distortion introduced on the edge of field of view. Furthermore, adopting the proposed afocal scanning system, we build a two-photon microscope with a field of view of 2.4 mm×2.4 mm and a lateral resolution of 1 μm. Using this system, the neuron axons in the mouse brain slice can be clearly resolved.