Postfilament supercontinuum on 100 m path in air
O.G. Kosareva, N. A. Panov, D. E. Shipilo, D. V. Mokrousova, И. Г. Николаева, E. Mitina, A. V. Koribut, Aleksei Reutov, G. E. Rizaev, A. Couairon, Aurélien Houard, Dmitry V. Skryabin, A. Saletskiy, A. B. Savel’ev, Л. В. Селезнев, А. А. Ионин, S. L. Chin
Abstract
Pulses at 744 nm with 90 fs duration, 6 mJ energy, and a weakly divergent wavefront propagate for more than 100 m and generate a filament followed by an unprecedently long high intensity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mo>≥</mml:mo> <mml:mn>1</mml:mn> <mml:mspace width="thinmathspace"/> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">T</mml:mi> <mml:mi mathvariant="normal">W</mml:mi> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>/</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msup> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mi mathvariant="normal">c</mml:mi> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msup> </mml:mrow> </mml:math> ) light channel. Over a 20 m long sub-section of this channel, the pulse energy is transferred continuously to the infrared wing, forming spectral humps that extend up to 850 nm. From 3D+time carrier-resolved simulations of 100 m pulse propagation, we show that spectral humps indicate the formation of a train of femtosecond pulses appearing at a predictable position in the propagation path.