Simultaneous correction of spherical and chromatic aberrations by dynamic hollow-cone illumination

利用透射电子显微镜（TEM）的64幅方位旋转图像，提出了一种新的动态空心锥照明下的波场恢复方法。通过利用球面和色差无傅立叶分量进行出射波场的恢复。通过对方位角旋转图像的积分傅立叶谱进行逆傅立叶变换获得的图像清楚地示出了出射波的真实的和虚分量的成功分离以及在轴向照明下超过信息极限的分辨率增强。另一种方法，以实现更高的空间分辨率也提出了使用三维傅立叶滤波方法应用于倾斜照明。该方法减小了色差引起的图像对比度下降，校正了球差、彗差和三倍像散引起的图像畸变，实现了1.在轴向照明下，分辨率比信息极限高4倍。

A novel wave field restoration method under dynamic hollow-cone illumination is demonstrated using a series of 64 azimuthally rotated images in transmission electron microscopy(TEM). The restoration of the exit wave field was performed by utilizing spherical and chromatic aberration-free Fourier components. The images obtained by inverse Fourier transform of the integrated Fourier spectrum for the azimuthally rotated images clearly showed successful separation of real and imaginary components of the exit wave and resolution enhancement beyond the information limit under axial illumination. Another way to achieve higher spatial resolution was also proposed using the three-dimensional Fourier filtering method applied to tilted illumination. In the approach, the degradation of image contrast caused by chromatic aberration was reduced and the image distortion caused by spherical aberration, coma aberration and three-fold astigmatism was corrected, resulting in the achievement of 1. 4 times higher resolution beyond the information limit under axial illumination.