Balyan Minas, Levonyan Levon, Trouni Karapet
Faculty of Physics, Yerevan State University, Alex Manoogian 1, Yerevan 0025, Armenia.
Institute of Applied Problems of Physics, Hr. Nersisyan 25, Yerevan 0014, Armenia.
Acta Crystallogr A Found Adv. 2021 Mar 1;77(Pt 2):149-159. doi: 10.1107/S2053273321001029.
The dynamical diffraction Talbot effect takes place inside a crystal, when a periodic object is illuminated by a plane or spherical X-ray wave which then falls on the crystal at an angle close to the Bragg angle for some reflection. Both theoretical consideration and numerical calculations show that the dynamical diffraction Talbot effect also takes place behind the crystal. The effect is accompanied by the dynamical diffraction pendulum effect and wave focusing. Expressions are found for the dynamical diffraction Talbot distance for areas before and after focusing. The spatial Fourier spectrum of the periodic object is obtained on the focusing plane. Detailed analysis when the periodic object is illuminated by a plane wave has shown new features of this effect. The dynamical diffraction Talbot effect in free space can be used to determine the structure of a periodic object, to determine the structure of an arbitrary object placed before or after the periodic object, and to determine structural defects and deformations of the crystal.
当周期性物体被平面或球面X射线波照射，且该X射线波以接近某一反射的布拉格角的角度入射到晶体上时，动态衍射塔尔博特效应会在晶体内发生。理论分析和数值计算均表明，动态衍射塔尔博特效应在晶体后方也会出现。该效应伴随着动态衍射摆效应和波聚焦。得出了聚焦前后区域的动态衍射塔尔博特距离的表达式。在聚焦平面上获得了周期性物体的空间傅里叶谱。对平面波照射周期性物体时的详细分析揭示了该效应的新特征。自由空间中的动态衍射塔尔博特效应可用于确定周期性物体的结构、确定置于周期性物体之前或之后的任意物体的结构，以及确定晶体的结构缺陷和形变。
