Balyan Minas K
Faculty of Physics, Department of Solid State Physics, Yerevan State University, Alex Manoogian 1, Yerevan 0025, Armenia.
J Synchrotron Radiat. 2015 Nov;22(6):1410-8. doi: 10.1107/S1600577515017804. Epub 2015 Oct 15.
Two-wave symmetric Bragg-case dynamical diffraction of a plane X-ray wave in a crystal with third-order nonlinear response to the electric field is considered theoretically. For certain diffraction conditions for a non-absorbing perfect semi-infinite crystal in the total reflection region an analytical solution is found. For the width and for the center of the total reflection region expressions on the intensity of the incidence wave are established. It is shown that in the nonlinear case the total reflection region exists below a maximal intensity of the incidence wave. With increasing intensity of the incidence wave the total reflection region's center moves to low angles and the width decreases. Using numerical calculations for an absorbing semi-infinite crystal, the behavior of the reflected wave as a function of the intensity of the incidence wave and of the deviation parameter from the Bragg condition is analyzed. The results of numerical calculations are compared with the obtained analytical solution.
从理论上考虑了平面X射线波在对电场具有三阶非线性响应的晶体中的两波对称布拉格情形动态衍射。对于全反射区域中无吸收的理想半无限晶体的某些衍射条件，找到了一个解析解。建立了关于入射波强度的全反射区域宽度和中心的表达式。结果表明，在非线性情况下，全反射区域存在于入射波的最大强度之下。随着入射波强度的增加，全反射区域的中心向低角度移动且宽度减小。利用对吸收性半无限晶体的数值计算，分析了反射波随入射波强度以及与布拉格条件的偏差参数的变化情况。将数值计算结果与得到的解析解进行了比较。
