Interaction of two edge dislocations in free-space propagation

• Published in: Chinese physics B Vol. 20; no. 1; pp. 352 - 357
• Main Author: 何德 高曾辉 闫红卫 吕百达
• Format: Journal Article
• Language: English
• Published: IOP Publishing 2011
• Subjects: 不稳定; 刃型位错; 相互作用; 自由空间传输; 高斯光束
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/20/1/014201

This paper studies in detail the interaction of two edge dislocations nested in a Gaussian beam propagating in free space. It shows that in free-space propagation the edge dislocations are unstable and vanish, and two noncanonical vortices with opposite topological charge take place when off-axis distances cl and c2 of two edge dislocations are nonzero, and the condition k2w08＋ 32c1c2（w02- 2C1C2）Z2 〉 0 is fulfilled （k-wave number, w0-waist width）. A noncanonical vortex appears when one off-axis distance is zero. However, one edge dislocation is stable when two edge dislocations are perpendicular and one off-axis distance is zero. Two perpendicular edge dislocations both with zero off-axis distance are also stable. The analytical results are illustrated by numerical examples.