Study of micro-cavities formed by optical breakdown under the influence of a magnetic field

Abstract

This article describes the change in geometric parameters of the quasi-periodic structure of the micro cavities inside the optical fiber. The quasi-periodic structure is a chain of localized cavities filled with oxygen. This structure is produced by the melting of the core of the fiber with a moving plasma spark, which appeared because of optical breakdown. While the quasi-periodic structure is being recorded, the fiber sample is placed between the poles of a permanent magnet with a magnetic field induction of 11.7 T. As a result of the effect of the magnetic field on the moving plasma, there is a change in the parameters of the quasi-periodic structure of the micro cavities. In the region with the highest magnetic field gradient, a 7% increase in the transverse dimensions of the cavities and a 9% increase in the longitudinal dimensions were observed. It was depending on the direction of plasma propagation. In the magnetic field, the effect of dividing the cavities into two unequal parts was observed. The main cavity was located at the axis of the fiber, an additional smaller cavity-satellite appeared at some distance from it in the radial direction.