Observation of two-times self-focusing of femtosecond laser beam in ZnO crystal by two-photon luminescence

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2018,（21）
• 页码范围: 1392-1396
• 页数: 5页
• 语种: 英文

摘要

By "seeing" the green two-photon luminescence,two separate focusing points are observed on the propagation axis of a converging femtosecond laser beam in a ZnO single crystal rod.It is found that the selffocusing effect makes a significant contribution to the formation of the first focusing point,while the second focusing point is caused by self-refocusing.The position of the first focusing point is in good agreement with the value predicted by a model developed by Chin and his co-workers.These experimental findings could be the unprecedented evidence for the self-focusing and refocusing effect of the femtosecond laser filament propagation in nonlinear media.