Real-Time Reconstruction of the Strong-Field-Driven Dipole Response

Abstract

The reconstruction of the full temporal dipole response of a strongly driven time-dependent system from a single absorption spectrum is demonstrated, only requiring that a sufficiently short pulse is employed to initialize the coherent excitation of the system. We apply this finding to the time-domain observation of Rabi cycling between doubly excited atomic states in the few-femtosecond regime. This allows us to pinpoint the breakdown of few-level quantum dynamics at the critical laser intensity near 2 TW=cm 2 in doubly excited helium. The present approach unlocks single-shot real-time-resolved signal reconstruction across timescales down to attoseconds for nonequilibrium states of matter. In contrast to conventional pump-probe schemes, there is no need for scanning time delays in order to access real-time information. The potential future applications of this technique range from testing fundamental quantum dynamics in strong fields to measuring and controlling ultrafast chemical and biological reaction processes when applied to traditional transient-absorption spectroscopy.

Bound-State Electron Dynamics Driven by Near-Resonantly Detuned Intense and Ultrashort Pulsed XUV Fields

“…Characteristic absorption lines are observed in the XUV-pulse spectrum after transmission through a moderately dense cloud of atoms or molecules. Hereby, measuring the transient absorption signal allows one to access the real-time dynamics of the XUV-excited system when it is driven by the NIR laser pulse [10] while First, we consider a two-level system for our numerical model, for which the Hamiltonian H 2lvl is described as a matrix with two states at energy E g = 0 eV and E e = 60.15 eV, for the ground and the excited state, respectively, which are coupled in dipole approximation by the dipole matrix element d ge = d eg = −0.035 a.u. (a.u.…”

Density-based one-dimensional model potentials for strong-field simulations in He, H2+ , and H2

“…For the case of the hydrogen molecule the correct asymptotic values of the potential turned out to be near to that of the hydrogen molecular ion with the same intermolecular distance. Experimental interest in strong field and attosecond processes of He [10,65,66] inspired us to calculate high-order-harmonic generation spectra by using our 1D model for He. It turned out that quantitatively correct spectra could be recovered with a simple scaling for different external electric fields.…”

“…The merits of these 1D model potentials may also pave the way to simulate properties of a dilute medium, like an atomic gas-jet, used in actual strong field or attosecond physics experiments with He [10,65,66]. Previously, this was done [67,68] by calculating Lewenstein's integral [16], but using the density-based model potentials and integrating the low dimensional TDSE has now become also an option [69].…”

Laser-Induced Control of the Optical Response of Aluminum Phthalocyanine Chloride Complexes Dissolved in Ethanol

“…In the gaseous phase the optical response of atomic and molecular targets can be controlled by XUV-NIR multipulse experiments which have been understood through laser-induced couplings between isolated electronic states [4][5][6][7], and also including vibrational couplings [8][9][10][11][12]. This approach also includes the possibility to selectively modify and control the dipole response with intense fields [13][14][15]. For more complex systems of molecules dissolved in the liquid phase, the intricacy of coherent lightmatter interaction increases, where typically the coupling to a bath leads to rather rapid decoherence effects [16][17][18][19][20].…”