The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due ...The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due to self-filtering,filamentation instability(beam splitting into filaments)either occurs at significantly larger values of the B-integral,or does not occur at all.In the latter case,there develops the honeycomb instability revealed in this work.This instability is the formation of a random honeycomb structure in the beam cross-section.It is shown that self-filtering can significantly increase the permissible values of the B-integral,at which the beam quality remains acceptable.展开更多
It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical mo...It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values.Although this discrepancy has been left unexplained at the moment,in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.展开更多
基金supported by the Ministry of Science and Higher Education of the Russian Federation(075-15-2020906,Center of Excellence‘Center of Photonics’)。
文摘The development of small-scale self-focusing in a nonlinear Kerr medium after preliminary self-filtering of a laser beam propagating in free space is studied numerically.It is shown that,under definite conditions,due to self-filtering,filamentation instability(beam splitting into filaments)either occurs at significantly larger values of the B-integral,or does not occur at all.In the latter case,there develops the honeycomb instability revealed in this work.This instability is the formation of a random honeycomb structure in the beam cross-section.It is shown that self-filtering can significantly increase the permissible values of the B-integral,at which the beam quality remains acceptable.
基金This work was supported by the Ministry of Science and Higher Education of the Russian Federation No.075-15-2020-906(Center of Excellence‘Center of Photonics’).
文摘It was shown experimentally that for a 65-fs 17-J pulse,the effect of filamentation instability,also known as small-scale self-focusing,is much weaker than that predicted by stationary and nonstationary theoretical models for high B-integral values.Although this discrepancy has been left unexplained at the moment,in practice no signs of filamentation may allow a breakthrough in nonlinear pulse post-compression at high laser energy.
