ICFO-Institut de Ciències Fotòniques, Mediterranean Technology Park, E-08860 Castelldefels (Barcelona), Spain.
Opt Lett. 2011 Apr 15;36(8):1347-9. doi: 10.1364/OL.36.001347.
We report on the experimental observation of speckle formation from a transparent crystal formed by a random distribution of nonlinear domains. The angular distribution of second-harmonic light generated by a transparent strontium barium niobate crystal is measured for different diameters of the fundamental beam and crystal thicknesses. Distinct manifestations of speckle pattern formation are found in these experiments. By using a theoretical Green's function formalism, we explain the reported observations as a result of the linear interference among the second-harmonic waves generated in all directions by each of the nonlinear domains forming the nonlinear crystal.
我们报告了在由非线性畴随机分布形成的透明晶体中观察到的散斑形成的实验结果。对于不同直径的基频光束和晶体厚度，我们测量了由透明铌酸锶钡晶体产生的二次谐波光的角度分布。在这些实验中发现了散斑图案形成的明显表现。通过使用理论格林函数形式理论，我们将报道的观察结果解释为形成非线性晶体的每个非线性畴在各个方向产生的二次谐波之间的线性干涉的结果。
