Testing the coherence of supercontinuum generated by optical vortex beam in water
He Zhang, Yun Zhang, Shuang Lin, Mingying Chang, Yu Miao, Yaqiu Wang, Anmin Chen, Yuanfei Jiang, Suyu Li, Mingxing Jin
Abstract
Abstract We experimentally study the femtosecond supercontinuum (SC) generation using an optical vortex (OV) beam in water. It is demonstrated that the topological charge of the OV beam has little influence on spectral broadening induced by filament, while it has strong influence on spectral intensity. Despite the SC induced by filamentation of optical vortices in air possesses orbital angular momentums (OAMs), the SC generated in water and sapphire loses OAM. However, the light at central wavelength possesses OAMs after filamentation in transparent Kerr media. This study is helpful to the understanding of the physical mechanism of femtosecond SC generation by optical vortices in water.