Abstract
The filamentation of ultraviolet and infrared nanosecond light pulses in fused silica is investigated theoretically and numerically. Emphasis is put on the action of a dynamical plasma response on two counterpropagating waves, amplified by Kerr self-focusing and stimulated Brillouin scattering (SBS). For a single unperturbed wave, laser filamentation takes place through a quasistationary balance between Kerr self-focusing and plasma defocusing, for which a variational approach reproduces global propagation features. However, such a quasistationary balance cannot hold as temporal modulational instability breaks up the pulse over electron recombination times. For two counterpropagating waves, we report similar instabilities which are justified through a plane-wave stability analysis. These instabilities originate from an intense backscattered wave that induces strong plasma contribution and thus destabilizes the pump near the entrance face of the material. Rapid phase modulations are then applied to suppress backscattering. We show that pump waves with broad enough bandwidths can inhibit SBS and thus prevent instability. The robustness of phase modulations against random fluctuations in the input pump pulse is finally addressed.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.