Entanglement is one of the most intriguing aspects quantum mechanics and lies at heart ongoing second revolution, where it a resource that used in key distribution, computing, teleportation. We report experiments demonstrating crucial role entanglement plays pump-probe involving ionization, which are hallmark novel research field attosecond science. demonstrate degree bipartite ion + photoelectron system, and, as consequence, vibrational coherence ion, can be controlled by tailoring spectral...

Circularly polarized light offers opportunities to probe symmetry-dependent properties of matter such as chirality and spin. Circular dichroism measurements typically require further intrinsic or extrinsic breaking symmetry by e.g. enantiomeric excess, orientation, magnetic fields direction-sensitive detectors. Here we introduce circular-dichroic attosecond transient absorption spectroscopy leveraging the angular momentum two circular-polarized pulses, both pump probe, in an isotropic...

The ability to control absorption by modifying the polarization of light presents an exciting opportunity experimentally determine orbital alignment features. Here, attosecond extreme ultraviolet (XUV) transient spectroscopy is used investigate dependence core exciton dynamics in LiF thin films at Li+ K edge. XUV pulses excite electrons from Li 1s level into conduction band, allowing for formation a p-orbital-like exciton, aligned along axis. A sub-5 fs near-infrared (NIR) probe pulse then...

Time-resolved extreme ultraviolet (XUV) transient absorption spectroscopy of iodomethane and iodobenzene photodissociation at the iodine pre-N4,5 edge is presented, using femtosecond UV pump pulses XUV probe from high harmonic generation. For both molecules molecular core-to-valence lines fade immediately, within pump-probe time-resolution. Absorption converging to atomic product emerge promptly in CH3I but are time-delayed C6H5I. We attribute this delay initial π → σ(*) excitation...

Measurements of the phase two-photon matrix elements are presented for resonant and antiresonant two-color ionization helium. A tunable, narrow-bandwidth, near-infrared (NIR) laser source is used extreme ultra-violet (XUV) high-harmonic generation (HHG). The 15th harmonic within (1+1') XUV+NIR ionization, tuned in out resonance with members 1s$n$p $^1$P$_1$ ($n=3,4,5$) Rydberg series, covering a broad spectral range high resolution. technique allows to observe characteristic rapid changes...

We report an experimental study of iodomethane attosecond transient absorption spectroscopy (ATAS) in the region iodine 4d core-to-valence/Rydberg excitation. Similar to previous atomic experiments, extreme ultraviolet near-infrared (XUV–NIR) delay-dependent absorbance changes reflect a light-induced phase due NIR-field driven AC Stark shift excited states, as well pathway interferences arising from couplings between neighboring states. As novel aspect molecular ATAS, we observe pronounced...

We present a setup for the generation of phase-locked attosecond extreme ultraviolet (XUV) pulse pairs. The pairs are generated by high harmonic (HHG) driven two near-infrared (NIR) pulses that produced using an actively stabilized Mach-Zehnder interferometer compatible with near-single cycle pulses. XUV can be delayed over range 400 fs sub-10-as delay jitter. validate precision and accuracy optical interferometry retrieving energies Rydberg states helium in pump-NIR probe photoelectron...

Abstract Transient absorption is a very powerful observable in attosecond experiments on atoms, molecules and solids frequently used employing phase-locked few-cycle infrared XUV laser pulses derived from high harmonic generation. We show numerically analytically that non-centrosymmetric systems, such as many polyatomic molecules, which-way interference enabled by the lack of parity conservation leads to new spectral features, which directly reveal electric field. The extension transient...

Understanding initial electron thermalization has relevance to both fundamental scientific knowledge and application the construction of novel devices. In this study, attosecond transient absorption is used directly measure times 38 $\pm$ 8 fs, 15 3 4.2 1 2.0 0.3 fs for Mg, Pt, Fe, Co, respectively. Through time dependent density function theory calculations, it shown that fast observed in Fe Co correlated with a strong local field effect. We find simple analytical model can be calculate...

Understanding initial electron thermalization has relevance to both fundamental scientific knowledge and application the construction of novel devices. In this study, attosecond transient absorption is used directly measure times 38 \ifmmode\pm\else\textpm\fi{} 8 fs, 15 3 4.2 1 2.0 0.3 fs for Mg, Pt, Fe, Co, respectively. Through time-dependent density-function theory calculations, it shown that fast observed in Fe Co correlated with a strong local-field effect. We find simple analytical...

The narrow bandgap semiconductor elemental tellurium (Te) has a unique electronic structure due to strong spin-orbit splitting and lack of inversion symmetry its helical lattice. Using broadband extreme ultraviolet core-level transient absorption, we measure simultaneously the coherently coupled photo-induced carrier lattice dynamics at Te N$_{4,5}$ edge initiated by few-cycle NIR pulse. Ultrafast excitation carriers leads excited A$_{\rm{1g}}$ phonon oscillation generation hot population...

Transient grating spectroscopy has become a mainstay among metal and semiconductor characterization techniques. Here we extend the technique towards shortest achievable timescales by using tabletop high-harmonic generation of attosecond extreme ultraviolet (XUV) pulses that diffract from transient gratings generated with 500-1000 nm sub-5 fs near-infrared (NIR) pulses. We demonstrate power (ATGS) investigating ultrafast photoexcited dynamics in an Sb semimetal thin film. ATGS provides...

Time-resolved XUV-IR photoion mass spectroscopy of naphthalene conducted with broadband as well wavelength-selected narrowband XUV pulses reveals a rising probability fragmentation characterized by lifetime 92 ± 4 fs. This is independent the excitation wavelength and same for all low appearance energy fragments recorded in experiment. Analysis experimental data conjunction statistical multistate vibronic model suggests that signals track vibrational redistribution on potential surface...

Attosecond extreme-ultraviolet (XUV) transient absorption spectroscopy measurements on the Peierls-distorted phase of semimetal antimony (Sb) are presented. After excitation by an ultrashort, broad band near-infrared (NIR) pulse, distortion is (partly) lifted causing well-known coherent phonon motion lattice. While overall observed dynamics generally follow a displacive model, delayed onset pump-induced carrier due to hot-carrier thermalization observed, as well large spectral dependence in...