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The advances in new smart materials are linked with attosecond subatomic technologies which can create entangled subatomic electron pairs by attosecond hard ultraviolet and soft X rays in addition to one-electron excitations by femtosecond optical pulses. The quantum infrastructure of nonequilibrium physical media in smart materials is provided by the Fermi and Bose gas of quasi-electron excitations, and the quantum infrastructure of their space-time scales is specified by the quantum mechanisms of two-electron attophysics and one-electron femtochemistry. The primary scale is subatomic (1.0 pm to 0.1 nm), and the next scale is supra-atomic (0.1 to 10.0 nm), being the scale of nanoelectromechanical systems of sensors and actuators that provide self-organization in the space-time hierarchy of nano-, micro-, meso-, and macroscopic dissipative structures of nonequilibrium physical media in smart materials. Here we show that any quantum nanoelectromechanical system can alternately be a sensor and an actuator of dissipative structures with a two-clock cycle: an attosecond sensor of entangled two-electron excitations and a femtosecond actuator of electromechanical motion modes in a nonequilibrium physical medium. For such nanoelectromechanical sensors-actuators, the motion rhythm is three orders of magnitude faster than for femtosecond nanomolecular sensors of one-electron excitations and nanomolecular actuators of vibrationrotation modes in nonequilibrium physical media.

With the advent of attoscience, it becomes possible to measure the ionization time delay of an electron that escapes its original quantum system after absorbing an XUV photon. It is well established that RABBIT (Re-construction of Attosecond Beating By Interference of Two-photon transitions) protocol is sensitive to ionization time delays with an attosecond accuracy. This technique offers a dual spectral and temporal resolution with a simple analysis when the channels are well separated [1] . It has mainly been applied to systems with few active electronic states. Only recently, RABBIT has successfully been applied to a gaseous/liquid water mixture where strong spectral congestion takes place [2] .

[EN]The coherent manipulation of the electron wavefunction at the atomic spatial and temporal scales is the fundamental breakthrough underlying far-reaching ultrafast phenomena as high-order harmonic radiation and attosecond pulse generation. In this work, we present a next step in the coherent control of matter waves by translating the concept of Talbot interferometry to the subnanomenter–femtosecond realm.We study the high-harmonic emission from a periodic system irradiated by an intense mid-infrared laser beam at grazing incidence. Our calculations show that Bloch electrons, once ionized, follow a sequence of ultrafast (femtosecond) revivals associated with the temporal Talbot effect. We demonstrate that these revivals leave a distinct signature in the high-frequency harmonic spectrum, in the form of structures extending beyond the main spectral cutoff, toward the x-rays. The reinterpretation of the process of high-order harmonic generation as the temporal realization of a Talbot–Lau interferometer suggests high-harmonic spectroscopy as an appropriate scheme to develop subnanometer ultrafast Talbot interferometry., We acknowledge support Ministerio de Ciencia e Innovación (PID2019-106910GB-I00). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 851201). We also acknowledge support from Junta de Castilla y León FEDER funds (Project No. SA287P18). AG-C acknowledges support from Ministerio de Educación, Cultura y Deporte (FPU18/03348). CH-G acknowledges Ministerio de Ciencia, Innovación, y Universidades for a Ramón y Cajal contract (RYC-2017-22745), co-funded by the European. Social Fund.

We present the implementation and utilisation of simple yet efficient low-dimensional models to simulate the response of atomic and molecular systems to light pulses, from the perturbative to the strong field regimes, with direct applications to attosecond sciences. The motivation is that solving the time-dependent Schrödinger equation for such simple models often proves more useful to get a clear physical picture than solving it for a full-fledged multi-dimensional model. We have focused the chapter on one- and two-dimensional approaches with illustrations on high-order harmonic generation and the photoionisation processes that are essential in an attophysics context. Within this framework, the topics we shall consider are the modelling of various aspects of high order harmonic generation in atoms and molecules (emission times, quantum path interferences, influences of the internuclear structure and dynamics) and the investigation of near threshold photoemission of a diatomic molecule with vibronic resolution from a time-dependent perspective. The advantages and limitations of low-dimensional models are discussed through the chapter.

The time it takes a bound electron to respond to the electromagnetic force of light sets a fundamental speed limit on the dynamic control of matter and electromagnetic signal processing. Time-integrated measurements of the nonlinear refractive index of matter indicate that the nonlinear response of bound electrons to optical fields is not instantaneous; however, a complete spectral characterization of the nonlinear susceptibility tensors--which is essential to deduce the temporal response of a medium to arbitrary driving forces using spectral measurements--has not yet been achieved. With the establishment of attosecond chronoscopy, the impulsive response of positive-energy electrons to electromagnetic fields has been explored through ionization of atoms and solids by an extreme-ultraviolet attosecond pulse or by strong near-infrared fields. However, none of the attosecond studies carried out so far have provided direct access to the nonlinear response of bound electrons. Here we demonstrate that intense optical attosecond pulses synthesized in the visible and nearby spectral ranges allow sub-femtosecond control and metrology of bound-electron dynamics. Vacuum ultraviolet spectra emanating from krypton atoms, exposed to intense waveform-controlled optical attosecond pulses, reveal a finite nonlinear response time of bound electrons of up to 115 attoseconds, which is sensitive to and controllable by the super-octave optical field. Our study could enable new spectroscopies of bound electrons in atomic, molecular or lattice potentials of solids, as well as light-based electronics operating on sub-femtosecond timescales and at petahertz rates.

The attosecond lighthouse is a method of using ultrafast wavefront rotation with high-harmonic generation to create a series of coherent, spatially separated attosecond pulses. Previously, temporal measurements by photoelectron streaking characterized isolated attosecond pulses created by manipulating the single-atom response. The attosecond lighthouse, in contrast, generates a series of pulses that spatially separate and become isolated by propagation. Here, we show that ultrafast wavefront rotation maintains the single-atom response (in terms of temporal character) of an isolated attosecond pulse over two octaves of bandwidth. Moreover, we exploit the unique property of the attosecond lighthouse—the generation of several isolated pulses—to measure the three most intense pulses. These pulses each have a unique spectrum and spectral phase.

The development of attosecond pulses across different photon energies is an essential precursor to performing pump–probe attosecond experiments in complex systems, where the potential of attosecond science1 can be further developed2,3. We report the generation and characterization of synchronized extreme ultraviolet (90 eV) and vacuum ultraviolet (20 eV) pulses, generated simultaneously via high-harmonic generation. The vacuum ultraviolet pulses are well suited for pump–probe experiments that exploit the high photo-ionization cross-sections of many molecules in this spectral region4 as well as the higher photon flux due to the higher conversion efficiency of the high harmonic generation process at these energies5. We temporally characterized all pulses using the attosecond streaking technique6 and the FROG-CRAB retrieval method7. We report 576 ± 16 as pulses at 20 eV and 257 ± 21 as pulses at 90 eV. Our demonstration of synchronized attosecond pulses at different photon energies, which are inherently jitter-free due to the common-path geometry implemented, offers unprecedented possibilities for pump–probe studies.

International audience; We review the present state of the application of attosecond lasers in molecular physics. Following the first synthesis and characterization of attosecond laser pulses a little more than a decade ago, the first applications in molecular physics have been published only in the last few years. These have yielded new insight into the coupling of multiple electronic degrees of freedom and that of electronic and nuclear degrees of freedom on the attosecond to few-femtosecond timescale. We review these first experiments as well as theoretical work that was carried out during the same period, and sketch some future molecular applications of attosecond pump–probe spectroscopy.

By compensating the gain-narrowing process, we achieved 6 mJ pulses with >130 nm full bandwidth at 1 kHz in a multipass amplifier. Out-of-loop CEP noise measurement of such a broadband configuration yielded

We present the isolation of single attosecond pulses for multi-cycle and few-cycle laser pulses from high harmonic generation in overdense plasmas, calculated with particle-incell simulations. By the combination of two laser pulses of equal amplitude and a small frequency shift between them, we demonstrate that it is possible to shorten the region in which the laser pulse is most intense, therefore restricting the generation of high harmonic orders in the form of attosecond pulses to a narrower time window. The creation of this window is achieved due to the combination of the laser pulse envelope and the slow oscillating wave obtained from the coherent sum of the two pulses. A parametric scan, performed with particle-in-cell simulations, reveals how the pulse isolation behaves for different input laser pulse lengths and which are the optimal frequency shifts between the two laser pulses in each case, giving the conditions for having a good isolation of an attosecond pulse when working with laser-plasma interaction in overdense targets. European Union and the Spanish Ministry of Economy and Competitivity (MINECO) (MAT2015-71119-R AEI/FEDER); Xunta de Galicia/FEDER (Agrup2015/11 (PC034)); Spanish Ministry of Education, Culture and Sports (MECD) (FPU14/00289) SI

Attosecond extreme-ultraviolet pulses have a complex space–time structure. However, at present, there is no method to observe this intricate detail; all measurements of the duration of attosecond pulses are, to some extent, spatially averaged. A technique for determining the full space–time structure would enable a detailed study of the highly nonlinear processes that generate these pulses as a function of intensity without averaging. Here, we introduce and demonstrate an all-optical method to measure the space–time characteristics of an isolated attosecond pulse. Our measurements show that intensity-dependent phase and quantum-path interference both play a key role in determining the pulse structure. In the generating medium, the attosecond pulse is strongly modulated in space and time. Propagation modifies but does not erase this modulation. Quantum-path interference of the single-atom response, previously obscured by spatial and temporal averaging, may enable measuring the laser-field-driven ion dynamics with sub-cycle resolution.

Experimental data supported by simulations indicate that the trajectories of relativistic electron bunches can be controlled at the attosecond timescale by precise adjustment of the relative phase in a two-colour field scheme. An enhancement in the harmonic yield is also reported. Energy coupling during relativistically intense laser–matter interactions is encoded in the attosecond motion of strongly driven electrons at the pre-formed plasma–vacuum boundary. Studying and controlling this motion can reveal details about the microscopic processes that govern a vast array of light–matter interaction phenomena, including those at the forefront of extreme laser–plasma science such as laser-driven ion acceleration1, bright attosecond pulse generation2,3 and efficient energy coupling for the generation and study of warm dense matter4. Here we experimentally demonstrate that by precisely adjusting the relative phase of an additional laser beam operating at the second harmonic of the driving laser it is possible to control the trajectories of relativistic electron bunches formed during the interaction with a solid target at the attosecond scale. We observe significant enhancements in the resulting high-harmonic yield, suggesting potential applications for sources of ultra-bright, extreme ultraviolet attosecond radiation to be used in atomic and molecular pump–probe experiments5,6.

Attosecond science represents a new frontier in atomic, molecular, and condensed matter physics, enabling one to probe the exceedingly fast dynamics associated with purely electronic dynamics in a wide range of systems. This paper presents a brief discussion of the technology required to generate attosecond light pulses and gives representative examples of attosecond science carried out in several laboratories. Attosecond transient absorption, a very powerful method in attosecond science, is then reviewed and several examples of gas phase and condensed phase experiments that have been carried out in the Leone/Neumark laboratories are described.

We have been developing two types of intense attosecond beam lines for investigating attosecond wavepackt dynamics in atoms and molecules. One produces an attosecond pulse train for attosecond Fourier transform spectroscopy by attosecond-pump/attosecond-probe scheme, while the other produces an intense isolated attosecond pulse for attosecond nonlinear optics.

Tracking and controlling electron dynamics in the interior of atoms, molecules as well as in solids is at the forefront of modern ultrafast science [1] , [2] , [3] , [4] , [5] . Time-resolved studies of these dynamics require attosecond temporal resolution that is provided by an ensemble of techniques consolidated under the term “attosecond metrology” [6] , [7] . This work reports the development and commissioning of what we refer to as next-generation attosecond beamline technology: the AS-1 attosecond beamline at the Max-Planck Institute of Quantum Optics. It consists of a phase-stabilized few-cycle laser system, for the generation of XUV radiation, and modules tailored for the spectral filtering and isolation of attosecond pulses as well as for their temporal characterization. The setup produces the shortest attosecond pulses demonstrated to date and combines them with advanced spectroscopic instrumentation (electron-, ion- and XUV-spectrometers). These pulses serve as temporally confined trigger events (attosecond streaking and tunneling spectroscopy) or probe pulses (attosecond absorption and photoelectron spectroscopy) enabling attosecond chronoscopy to be applied to a broad range of systems belonging to the microcosm.

Chemical reactions are triggered by the dynamics of valence electrons in molecular orbitals. These motions typically unfold on a subfemtosecond scale and have eluded real-time access until now. Attosecond spectroscopy (an attosecond is 10−18 seconds), first applied to tracking electronic transitions from one quantum state to another, has now been extended to follow the hyperfast (subfemtosecond) motion of electron wavepackets in the valence shell — the bond-forming electrons — of krypton ions. This first proof-of-principle demonstration uses a simple system, but the expectation is that attosecond transient absorption spectroscopy of this type will ultimately reveal the elementary electron motions in molecules and solid-state materials that determine physical, chemical and biological properties. Attosecond technology (1 as = 10−18 S) promises the tools needed to directly probe electron motion in real time. These authors report attosecond pump–probe measurements that track the movement of valence electrons in krypton ions. This first proof-of-principle demonstration uses a simple system, but the expectation is that attosecond transient absorption spectroscopy will ultimately also reveal the elementary electron motions that underlie the properties of molecules and solid-state materials. The superposition of quantum states drives motion on the atomic and subatomic scales, with the energy spacing of the states dictating the speed of the motion. In the case of electrons residing in the outer (valence) shells of atoms and molecules which are separated by electronvolt energies, this means that valence electron motion occurs on a subfemtosecond to few-femtosecond timescale (1 fs = 10−15 s). In the absence of complete measurements, the motion can be characterized in terms of a complex quantity, the density matrix. Here we report an attosecond pump–probe measurement of the density matrix of valence electrons in atomic krypton ions1. We generate the ions with a controlled few-cycle laser field2 and then probe them through the spectrally resolved absorption of an attosecond extreme-ultraviolet pulse3, which allows us to observe in real time the subfemtosecond motion of valence electrons over a multifemtosecond time span. We are able to completely characterize the quantum mechanical electron motion and determine its degree of coherence in the specimen of the ensemble. Although the present study uses a simple, prototypical open system, attosecond transient absorption spectroscopy should be applicable to molecules and solid-state materials to reveal the elementary electron motions that control physical, chemical and biological properties and processes.

International audience; ELI-ALPS, one of the three pillars of the Extreme Light Infrastructure (ELI) project, will be in a unique position to offer dedicated experimental platforms for ultrashort time-resolved investigations of strongly excited dynamical systems. The state-of-the-art surface plasma attosource (SPA) beamlines at ELI-ALPS are being designed and developed to enable new directions in plasma-based attoscience research. The SPA beamlines will be driven by ultrashort, high peak power, high repetition rate lasers based on the latest technology and are aimed to develop previously unavailable attoscience experimental platforms employing surface high-harmonic generation process. This endeavor involves research and development challenges and careful considerations. Here we discuss the physics of plasma attosources and their characteristics under such extreme conditions and the beamline functionalities that would facilitate these objectives. Finally, we delineate the initial research possibilities with these sophisticated instruments. (C) 2018 Optical Society of America

We consider here the extension of four-dimensional (4D) electron imaging methodology to the attosecond time domain. Specifically, we discuss the generation of attosecond electron pulses and the in situ probing with electron diffraction. The free electron pulses have a de Broglie wavelength on the order of picometers and a high degree of monochromaticity (ΔE/E_0 ≈ 10−4); attosecond optical pulses have typically a wavelength of 20 nm and ΔE/E_0 ≈ 0.5, where E_0 is the central energy and ΔE is the energy bandwidth. Diffraction, and tilting of the electron pulses/specimen, permit the direct investigation of electron density changes in molecules and condensed matter. We predict the relevant changes in diffraction caused by electron density motion and give two examples as prototype applications, one that involves matter-field interaction, and the other is that of change in bonding order. This 4D imaging on the attosecond time scale is a pump–probe approach in free space and with free electrons.

Using a high-power attosecond pulse train, we investigated attosecond dynamics in molecules. We also developed a high-energy waveform synthesizer for isolated attosecond pulses.

Here we demonstrate the first intense optical attosecond pulses synthesized in the visible and nearby spectral ranges and their use for revealing the nonlinear response time of bound electrons of Kr atoms.

Attoscience is the study of physical processes that occur in less than a fraction of a cycle of visible light, in times less than a quadrillionth of a second. The motion of electrons inside atoms and molecules that are undergoing photoionization or chemical change falls within this time scale, as does the plasma motion that causes the reflectivity of metals. The techniques to study motion on this scale are based on careful control of strong-field laser-atom interactions. These techniques and new research opportunities in attosecond spectroscopy are reviewed.

An attosecond high-density electron bunch is produced by an intense short-pulse TEM10+TEM01-mode laser. The transverse ponderomotive force of the TEM10+TEM01-mode laser confines pre-accelerated electrons in the transverse direction, and at the same time the laser longitudinal electric field accelerates the electrons. Our three-dimensional particle simulations show that the pre-accelerated electrons are accelerated to a few hundreds MeV and are compressed to ∼499 attoseconds with a low energy spread (∼±3.5 %). The electron density of the attosecond bunch reaches ∼43 times as high as the initial number density. Such the attosecond electron bunch is now available to attophysics.

The material presented in this chapter is based on important advances realized in “attophysics” which make feasible to follow the motion of electrons in atoms and molecules with attosecond-level time resolution. In this context, time-delays have been recently determined in the process of photoionization by extreme-ultra-violet (XUV) pulses and the question of the significance of these measured delays arises. As we shall outline here, numerical experiments show that they are intimately related to the structure of the ionized species’ continuous spectrum. Another point addressed here is that, in experiments, the measurements have the common characteristic to be performed in the presence of an auxiliary infra-red (IR) field, used to “clock” the timing of the process. This implies to adapt the theory treatment to handle such “two-color” photoionization processes. We review a systematic analysis of these features that are characteristic of this class of electronic transitions, when viewed in the time domain.

Emission of the two electrons released from nonsequential double ionization of argon atoms is anticorrelated at lower laser intensities but is correlated at higher laser intensities. Such a transition is caused by the momentum change of recollision-induced-ionization (RII) electrons. At lower laser intensities, the Coulomb repulsion between the two RII electrons dominates the motion of electrons and pushes them leaving the laser field back-to-back. At higher laser intensities, the drift momentum obtained from the laser field dominates the motion of electrons and drives them leaving the laser field side-by-side.

Molecular Coulomb explosion has been utilized as a precise temporal clock for probing ultrafast motion of nucleus and electrons during chemical reactions. With an intense attosecond pulse train in the extreme ultraviolet region, we were able to image attosecond molecular Coulomb explosion via two photon double ionization process. The present autocorrelation measurement, from which the duration of the attosecond pulse train was determined to be 300 as, serves as the first step toward a pump-and-probe measurement of molecular dynamics with attosecond temporal resolution.

Attosecond electron wavepackets are produced when an intense laser field ionizes an atom or a molecule(1). When the laser field drives the wavepackets back to the parent ion, they interfere with the bound wavefunction, producing coherent subfemtosecond extreme-ultraviolet light bursts. When only a single return is possible(2,3), an isolated attosecond pulse is generated. Here we demonstrate that by modulating the polarization of a carrier-envelope phase-stabilized short laser pulse(4), we can finely control the electron-wavepacket dynamics. We use high-order harmonic generation to probe these dynamics. Under optimized conditions, we observe the signature of a single return of the electron wavepacket over a large range of energies. This temporally confines the extreme-ultraviolet emission to an isolated attosecond pulse with a broad and tunable bandwidth. Our approach is very general, and extends the bandwidth of attosecond isolated pulses in such a way that pulses of a few attoseconds seem achievable. Similar temporal resolution could also be achieved by directly using the broadband electron wavepacket. This opens up a new regime for time-resolved tomography of atomic or molecular wavefunctions(5,6) and ultrafast dynamics.

Numerical solutions of the time-dependent Schrodinger equation for a 1D model non-Born–Oppenheimer H are used to illustrate the nonlinear nonperturbative response of molecules to intense (I ≥ 1013 W/cm2), ultrashort (t < 10 fs) laser pulses. Molecular high-order harmonic generation (MHOHG) is shown to be an example of such response and the resulting nonlinear photon emission spectrum is shown to lead to the synthesis of single attosecond (10−18 s) pulses. Application of such ultrashort pulses to the H system results in localized electron wavepackets whose motion can be detected by asymmetry in the photoelectron spectrum generated by a subsequent probe attosecond pulse, thus leading to measurement of electron motion in molecules on the attosecond time scale. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004

Subfemtosecond light pulses can be obtained by superposing several high harmonics of an intense laser pulse. Provided that the harmonics are emitted simultaneously, increasing their number should result in shorter pulses. However, we found that the high harmonics were not synchronized on an attosecond time scale, thus setting a lower limit to the achievable x-ray pulse duration. We showed that the synchronization could be improved considerably by controlling the underlying ultrafast electron dynamics, to provide pulses of 130 attoseconds in duration. We discuss the possibility of achieving even shorter pulses, which would allow us to track fast electron processes in matter.

Temporal probing of a number of fundamental dynamical processes requires intense pulses at femtosecond or even attosecond (1 as = 10-18 s) timescales. A frequency ‘comb’ of extreme-ultraviolet odd harmonics can easily be generated in the interaction of subpicosecond laser pulses with rare gases: if the spectral components within this comb possess an appropriate phase relationship to one another, their Fourier synthesis results in an attosecond pulse train1,2. Laser pulses spanning many optical cycles have been used for the production of such light bunching3,4, but in the limit of few-cycle pulses the same process produces isolated attosecond bursts5,6. If these bursts are intense enough to induce a nonlinear process in a target system7,8,9, they can be used for subfemtosecond pump–probe studies of ultrafast processes. To date, all methods for the quantitative investigation of attosecond light localization4,6,10 and ultrafast dynamics11 rely on modelling of the cross-correlation process between the extreme-ultraviolet pulses and the fundamental laser field used in their generation. Here we report the direct determination of the temporal characteristics of pulses in the subfemtosecond regime, by measuring the second-order autocorrelation trace of a train of attosecond pulses. The method exhibits distinct capabilities for the characterization and utilization of attosecond pulses for a host of applications in attoscience.

The amplitude and frequency of laser light can be routinely measured and controlled on a femtosecond (10(-15) s) timescale. However, in pulses comprising just a few wave cycles, the amplitude envelope and carrier frequency are not sufficient to characterize and control laser radiation, because evolution of the light field is also influenced by a shift of the carrier wave with respect to the pulse peak. This so-called carrier-envelope phase has been predicted and observed to affect strong-field phenomena, but random shot-to-shot shifts have prevented the reproducible guiding of atomic processes using the electric field of light. Here we report the generation of intense, few-cycle laser pulses with a stable carrier envelope phase that permit the triggering and steering of microscopic motion with an ultimate precision limited only by quantum mechanical uncertainty. Using these reproducible light waveforms, we create light-induced atomic currents in ionized matter; the motion of the electronic wave packets can be controlled on timescales shorter than 250 attoseconds (250 x 10(-18) s). This enables us to control the attosecond temporal structure of coherent soft X-ray emission produced by the atomic currents--these X-ray photons provide a sensitive and intuitive tool for determining the carrier-envelope phase.

We demonstrate 1.7-mJ optical waveforms based on induced-phase modulation for generating sub-femtosecond optical pulses. Using custom-designed double-chirped mirrors and a spatial light modulator, such optical waveforms will become a versatile tool for strong-field attoscience.

Recently the measurement of X-ray pulses approaching the attosecond frontier was published (M. Drescher et al ., Science 291 (2001) p. 1923). The attosecond laser pulse enables the study and control of the motion of electrons inside atoms. In this paper we develop and solve the modified Schrodinger equation (MSE) which describes the interaction of electrons with its surroundings in an atom. This interaction can be detected only using an attosecond laser pulse within the relaxation time of the interaction which is of the order of 10 attoseconds.

In this paper the interaction of attosecond laser pulses with matter is investigated. The scattering and motion of heat carriers as well as the external force are considered. The heat transport is described by the thermally forced Klein-Gordon or thermal modified telegraph equation depending on the ratio of the scattering and potential motion. In the case of the thermal Heisenberg type relation V ‰ ∽ E ( ‰ is the relaxation time and V is the potential) the heat transport is described by the thermal distortionless damped wave equation. In this paper the Klein-Gordon, modified telegraph 1 equation and wave equation are solved.

Here we present a successful combination of an attosecond beamline with a COLTRIMS apparatus, which we refer to as AttoCOLTRIMS. The setup provides either single attosecond pulses or attosecond pulse trains for extreme ultraviolet-infrared pump-probe experiments. We achieve full attosecond stability by using an active interferometer stabilization. The capability of the setup is demonstrated by means of two measurements, which lie at the heart of the COLTRIMS detector: firstly, we resolve the rotating electric field vector of an elliptically polarized few-cycle infrared laser field by attosecond streaking exploiting the access to the 3D momentum space of the charged particles. Secondly, we show streaking measurements on different atomic species obtained simultaneously in a single measurement making use of the advantage of measuring ions and electrons in coincidence. Both of these studies demonstrate the potential of the AttoCOLTRIMS for attosecond science., Review of Scientific Instruments, 85 (10), ISSN:0034-6748, ISSN:1089-7623

Many amateur photographers are disappointed when they discover that their shots of fast-moving objects are blurred beyond recognition. The most likely reason for this is that the exposure time was not short enough to freeze the motion. In contrast, modern ultrahigh-speed cameras can take up to a million images every second and can capture motion that is normally imperceptible to the human eye. By projecting the photographs on a screen in sequence, the action can be replayed in slow motion. While these techniques are ideal for studying macroscopic objects, how can we possibly follow the motion of atoms and electrons?

Measurements on the attosecond timescale had been limited to the dynamics of electrons in an atomic gas. But a record has now been set in a quite different context — the photoemission of electrons from a surface.

The tunnelling of a bound electron out of an atom in a laser field is a well-known quantum-mechanical process. But it happens very quickly, and it takes some fast work with X-rays and lasers to see it in action.

Intense isolated attosecond pulses with >100 eV photon energy are produced via high-order-harmonic generation using 80mJ sub-5 fs laser pulses. The generation of these attosecond pulses and their application to non-linear XUV-XUV pum-probe experiments is discussed.

Attosecond transient absorption spectroscopy, using ultrabroadband isolated attosecond pulses characterized using the PROOF (phase retrieval by omega oscillation filtering) technique, is demonstrated as a powerful tool for capturing the sub-laser-cycle dynamics in laser-dressed atoms.