CC BY
14LS-I-15
Hollow-core fibers destruction under high power laser radiation
I. Bufetov1, A. Kolyadin1, A. Kosolapov1
1Fiber Optics Research Center of RAS, HCF Lab, Moscow, Russian Federation
The first detailed quantitative study of the catastrophic destruction of hollow-core fibers under the action of pulsed (Q-switched + mode-locked) laser radiation containing evaluation of key physical processes will be presented. The propagation of an optical discharge (OD) along hollow-core optical fibers (HCFs) was investigated experimentally (Fig.1)
Fig1. Picture of an OD propagating through HCF.
Numbers indicate HCF (1), OD (2), and laser radiation launch unit (3).
Outwardly this process looks very similar to the well-known fiber fuse effect in solid core fibers [1]. Silica-based revolver-type HCFs (RFs) filled with atmospheric air were used as test samples in our experiments [2]. We observed that the average propagation velocity of an OD along the RFs (VAV) depends on the properties of the medium around the silica structure of the RF. It is shown that the value of VAV changes by approximately a factor of three, depending on whether the OD is moving along a polymer coated or uncoated RF (Fig.2).
3.0
2.5
t, ms
Fig.2. VAV(t) for OD propagation through HCF. Numbers indicate regions of OD initiation (1), polymer coated HCF (2, 4), uncoated HCF (3).
The value of VAV practically does not change when the polymer is replaced by an immersion liquid (such as glycerol) or liquid gallium. By analyzing the destruction region's patterns that appear in the fiber cladding after an OD propagation, we propose the physical picture of the phenomenon. A consistent physical picture of an OD propagating along an RF (as a version of
HCFs) in our experiments includes the following processes: 1. Initiation and propagation of a laser supported detonation wave under the action of a picosecond laser pulses. 2. Movement of the attenuating shock wave along a RF during the period between picosecond pulses. 3. The process of a iterated detonation wave initiation in front of the shock wave by the next picosecond pulse. 4. A special mode of OD self-initiation at spiky splinters of silica capillaries after ms time intervals between Q-switch laser pulses.
The study was supported by the Russian Foundation for Basic Research (Project No. 18-0200324).
References
[1] R. Kashyap, "The Fiber Fuse - from a curious effect to a critical issue: A 25th year retrospective," Opt. Express 21(5), 6422-6441 (2013).
[2] A. N. Kolyadin, A. F. Kosolapov, and I. A. Bufetov, "Optical discharge propagation along hollow-core optical fibres", Quantum Electronics 48(12), 1138-1142 (2018).
