title: Ionization with low-frequency fields in the tunneling regime.
abstract: Strong-field ionisation surprises with richness beyond current understanding despite decade long investigations. Ionisation with mid-IR light has promptly revealed unexpected kinetic energy structures that seem related to unanticipated quantum trajectories of the electrons. We measure first 3D momentum distributions in the deep tunneling regime (γ = 0.3) and observe surprising new electron dynamics of near-zero momentum electrons and extremely low momentum structures, below the eV, despite very high quiver energies of 95 eV. Such level of high-precision measurements at only 1 meV above the threshold, despite 5 orders higher ponderomotive energies, has now become possible with a specifically developed ultrafast mid-IR light source in combination with a reaction microscope, thereby permitting a new level of investigations into mid-IR recollision physics.
authors.affiliation: ICFO-Institut de Ciences Fotoniques, 08860 Castelldefels (Barcelona), Spain.
authors.forename: J
authors.initials: J
authors.lastname: Dura
authors.forename: N
authors.initials: N
authors.lastname: Camus
authors.forename: A
authors.initials: A
authors.lastname: Thai
authors.forename: A
authors.initials: A
authors.lastname: Britz
authors.forename: M
authors.initials: M
authors.lastname: Hemmer
authors.forename: M
authors.initials: M
authors.lastname: Baudisch
authors.forename: A
authors.initials: A
authors.lastname: Senftleben
authors.forename: C D
authors.initials: CD
authors.lastname: Schröter
authors.forename: J
authors.initials: J
authors.lastname: Ullrich
authors.forename: R
authors.initials: R
authors.lastname: Moshammer
authors.forename: J
authors.initials: J
authors.lastname: Biegert
references.citation: Phys Rev Lett. 2012 Aug 31;109(9):093001
references.pmid: 23002830
references.citation: Phys Rev Lett. 2012 Jul 27;109(4):043001
references.pmid: 23006081
references.citation: Phys Rev Lett. 2012 Aug 17;109(7):073004
references.pmid: 23006367
references.citation: Opt Lett. 2010 Oct 1;35(19):3204-6
references.pmid: 20890334
references.citation: Phys Rev Lett. 2012 Aug 24;109(8):083002
references.pmid: 23002743
references.citation: Science. 2011 Jan 7;331(6013):61-4
references.pmid: 21163963
references.citation: Opt Express. 2010 Jun 21;18(13):14293-300
references.pmid: 20588564
references.citation: Phys Rev Lett. 2010 Oct 22;105(17):173901
references.pmid: 21231046
references.citation: Phys Rev Lett. 2012 Jan 20;108(3):033201
references.pmid: 22400738
references.citation: Phys Rev Lett. 2008 Dec 5;101(23):233001
references.pmid: 19113543
references.citation: Phys Rev Lett. 2010 Dec 17;105(25):253002
references.pmid: 21231586
references.citation: Nature. 2004 Dec 16;432(7019):867-71
references.pmid: 15602553
references.citation: Phys Rev Lett. 2010 Sep 10;105(11):113003
references.pmid: 20867569
references.citation: Phys Rev Lett. 2009 Aug 28;103(9):093001
references.pmid: 19792794
references.citation: Opt Lett. 2011 Oct 1;36(19):3918-20
references.pmid: 21964141