Attosecond sublevel beating and nonlinear dressing on the 3d-to-5p and 3p-to-5s core-transitions at 913 eV and 2104 eV in krypton

Abstract

Applying extreme ultraviolet (XUV) transient absorption spectroscopy, the dynamics of the two laser dressed transitions 3d-to-5p and 3p-to-5s at photon energies of 91.3 eV and 210.4 eV were examined with attosecond temporal resolution. The dressing process was modeled with density matrix equations which are found to describe very accurately both the experimentally observed transmission dynamics and the linear and nonlinear dressing oscillations at 0.75 PHz and 1.5 PHz frequencies. Furthermore, using Fourier transform XUV spectroscopy, quantum beats from the 3d-3d and 3p-3p sublevels at 0.3 PHz and 2.0 PHz were experimentally identified and resolved.

Modification of laser-induced state in atomic attosecond transient absorption by the XUV pulse pair

“…Attosecond transient absorption (ATA) spectrum generated by an attosecond XUV pulse in the combination with a fewfemtosecond infrared (IR) pulse has been developed as an alloptical method widely applied for studying the interaction of laser fields with matter [1][2][3][4][5][6][7][8][9][10][11][12]. ATA spectrum has been proven to be an excellent tool for probing the ultrafast subfemtosecond or attosecond electron dynamics not only in atoms [13][14][15][16], but also in molecules [17][18][19][20][21][22] and in solids [23][24][25][26][27]. For atomic systems, the ATA spectrum displays several interesting features including the light-induced states [4,21], Autler-Townes splitting [28][29][30], hyperbolic sidebands associated with perturbed free induction decay [31], AC Stark shift [32], and so on, indicating various physical processes motivated by the electronic motion.…”

Attosecond Transient Absorption Below the Excited States

“…The majority of the current ATAS methods use an isolated XUV pulse with a wide spectral bandwidth covering many intrinsic atomic and molecular levels, and previously unobserved ultrafast dynamics have been discovered, such as the light-inducedstate [28][29][30][31][32][33][34], the sub-cycle AC Stark shift [28], Autler-Townes splitting [35], hyperbolic sidebands [15,29,32,33], and quantum beats [8,36,37]. However, the dynamics for the case where the central photon energy of the isolated XUV pulse is below the first excited state has been largely ignored.…”