Livadaru Lucian, Mutus Josh, Wolkow Robert A
Department of Physics, National Institute for Nanotechnology, University of Alberta, National Research Council, Edmonton, AB, Canada.
Ultramicroscopy. 2008 Apr;108(5):472-80. doi: 10.1016/j.ultramic.2007.08.001. Epub 2007 Aug 7.
It is now a well-known fact that the phase of electron waves is altered by external magnetic fields via the Aharonov-Bohm effect. This implies that any electron interference effects will be to some degree affected by the presence of such fields. In this study we examine the distortion effects of external (constant and variable) magnetic fields on electron interference and holography. For digital holography, the reconstruction of the object is done via numerical calculations and this leaves the door open for correcting phase distortions in the hologram reconstruction. We design and quantitatively assess such correction schemes, which decidedly depend on our knowledge of the magnetic field values in the holographic recording process. For constant fields of known value we are able to correct for magnetic distortions to a great extent. We find that variable fields are more destructive to the holographic process than constant fields. We define two criteria, related respectively to global and local contrast of the hologram to establish the maximum allowed external field which does not significantly hinder the accuracy of in-line holographic microscopy with electrons.
现在众所周知，电子波的相位会通过阿哈罗诺夫 - 玻姆效应被外部磁场改变。这意味着任何电子干涉效应都会在某种程度上受到此类磁场存在的影响。在本研究中，我们研究了外部（恒定和可变）磁场对电子干涉和全息术的畸变效应。对于数字全息术，物体的重建是通过数值计算完成的，这为校正全息图重建中的相位畸变打开了大门。我们设计并定量评估了此类校正方案，这些方案显然依赖于我们对全息记录过程中磁场值的了解。对于已知值的恒定磁场，我们能够在很大程度上校正磁畸变。我们发现可变磁场对全息过程的破坏比恒定磁场更大。我们定义了两个分别与全息图的全局和局部对比度相关的标准，以确定不会显著阻碍电子在线全息显微镜精度的最大允许外部磁场。
