倍频过程中复合涡旋拓扑荷数的倍频效应

Frequency Doubling Effect of Topological Charge of Composite Vortex in Frequency Doubling Process

利用非线性频率转换过程获得高阶涡旋光场的方法得到了研究人员的广泛关注,目前关于该领域的研究大都集中在拉盖尔-高斯光束方面,而针对复合涡旋的非线性频率转换过程的研究不多。从理论方面分析了复合涡旋的倍频过程,得出了其倍频光场的涡旋分布,证明了复合涡旋倍频过程中拓扑荷数守恒。在实验方面,基于非线性光学晶体磷酸钛氧钾,验证了拉盖尔-高斯涡旋光倍频过程中的拓扑荷数守恒。基于马赫-曾德尔干涉仪产生复合涡旋光,并研究了其倍频过程。实验结果表明,复合涡旋光在倍频过程中的拓扑荷数仍然守恒。

Higher-order vortex light field generated through the process of nonlinear frequency conversion gets the researcher＇s attention, but the most researches on this field concentrate on Laguerre-Gaussian beams rather than the nonlinear frequency conversion process of composite vortex. The process of frequency doubling of composite vortex is analyzed theoretically, and the vortex distribution of frequency doubling light field is obtained. Via theoretically studying, the topological charge conservation in the frequency doubling process of composite vortex is demonstrated. The topological charge conservation of Laguerre-Gaussian vortex light in the frequency doubling process based on nonlinear potassium titanyl phosphate optical crystal is experimentally demonstrated. Furthermore, composite vortex light is generated based on Mach-Zenhder interferometer, and its frequency doubling process is studied. Experimental results confirm the topological charge conservation in the frequency doubling process of composite vortex light.