A5037605093- Laser-Matter Interactions and Applications
- Orbital Angular Momentum in Optics
- Laser-Plasma Interactions and Diagnostics
- Advanced Fiber Laser Technologies
- Spectroscopy and Quantum Chemical Studies
- Information Science and Libraries
- Photoreceptor and optogenetics research
- Molecular spectroscopy and chirality
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Cold Atom Physics and Bose-Einstein Condensates
- Archaeology and Cultural Heritage
- Brazilian Legal Issues
- Photochemistry and Electron Transfer Studies
- Crystallization and Solubility Studies
- Brazilian cultural history and politics
- Sperm and Testicular Function
- Terahertz technology and applications
- Quantum chaos and dynamical systems
- Business and Management Studies
- Magneto-Optical Properties and Applications
- Environmental Toxicology and Ecotoxicology
- Photorefractive and Nonlinear Optics
- Digital and Traditional Archives Management
- Quantum optics and atomic interactions
Imperial College London
2022-2024
Madrid Institute for Advanced Studies
2024
Universidad Autónoma de Madrid
2023-2024
Universidad de Salamanca
2016-2023
Universidade Estadual Paulista (Unesp)
2014
Universidade de Marília
2014
Pulses with a twist and torque Structured light beams can serve as vortex carrying optical angular momentum have been used to enhance communications imaging. Rego et al. generated dynamic pulses by interfering two incident time-delayed different orbital momenta through the process of high harmonic generation. A controlled time delay between allowed extreme-ultraviolet beam exhibit time-dependent momentum, called self-torque. Such could potentially be manipulate nanostructures atoms on...
High-order harmonic generation (HHG) has been recently proven to produce extreme-ultraviolet (XUV) vortices from the nonlinear conversion of infrared twisted beams. Previous works have demonstrated a linear scaling law vortex charge with order. We demonstrate that this simple hides an unexpectedly rich scenario for buildup orbital angular momentum (OAM) due nonperturbative behavior HHG. The complexity these XUV beams appears only when HHG is driven by nonpure modes, where OAM content...
The extreme nonlinear optical process of high-harmonic generation (HHG) makes it possible to map the properties a laser beam onto radiating electron wave function and, in turn, emitted x-ray light. Bright HHG beams typically emerge from longitudinal phased distribution atomic-scale quantum antennae. Here, we form transverse necklace-shaped array linearly polarized emitters, where orbital angular momentum conservation allows us tune line spacing and divergence ultraviolet soft combs. on-axis...
Abstract We investigate theoretically the generation of extreme-ultraviolet (EUV) beams carrying fractional orbital angular momentum. To this end, we drive high-order harmonic with infrared conical refraction (CR) beams. show that emitted in EUV/soft x-ray regime preserve characteristic signatures driving beam, namely ringlike transverse intensity profile and CR-like polarization distribution. As a result, through spin momentum conservation, are momentum, they can be synthesized into...
Vortex light beams are structures of the electromagnetic field with a spiral phase ramp around point-phase singularity. These vortices have many applications in optical regime, ranging from trapping and quantum information to spectroscopy microscopy. The extension into extreme-ultraviolet (XUV)/X-ray regime constitutes significant step forward bring those nanometer or even atomic scale. recent development new generation X-ray sources, refinement other techniques, such as harmonic generation,...
High-order harmonic generation stands as a unique nonlinear optical up-conversion process, mediated by laser-driven electron recollision mechanism, which has been shown to conserve energy, momentum, and spin orbital angular momentum. Here we present theoretical simulations demonstrate that this process also conserves mixture of the latter, torus-knot momentum $J_\gamma$, producing high-order harmonics with driving pulses are invariant under coordinated rotations. We charge $J_\gamma$ emitted...
We introduce an ultrafast all-optical approach for efficient chiral recognition that relies on the interference between two low-order nonlinear processes are ubiquitous in optics: sum-frequency generation and third-harmonic generation. In contrast to traditional generation, our encodes medium's handedness intensity of emitted harmonic signal, rather than its phase, it enables full control over enantiosensitive response. show how, by sculpting sub-optical-cycle oscillations driving laser...
Polarization engineering and characterization of coherent high-frequency radiation are essential to investigate control the symmetry properties light–matter interaction phenomena at their most fundamental scales. This work demonstrates that polarization high-harmonic generation provides an excellent ellipsometry tool can fully retrieve both amplitude phase a strong-field-driven dipole response. The is realized by transient nonlinear grating coherently induced two noncollinear counterrotating...
The nature of high-order harmonic generation process limits the harmonics emission to linear polarization. In this paper, we review recent progress generate elliptically or circularly polarized high-harmonic EUV pulses. We further demonstrate how complete control polarization state isolated pulse can be realized today by noncollinear focusing two driving pulses with identical ellipticity but counter-rotating helicity. This paper opens a path towards study fastest dynamics--down attosecond...
Optical vortices are structures of the electromagnetic field with a spiral phase ramp about point-phase singularity, carrying orbital angular momentum (OAM). Recently, OAM has been imprinted to short-wavelength radiation through high-order harmonic generation (HHG), leading emission attosecond twisted beams in extreme-ultraviolet (XUV) regime. We explore details mapping driving vortex its spectrum. In particular, we show that geometry is convoluted, arising from superposition contribution...
A survey conducted on the EU Notification of New Substances (NONS) database suggested that for industrial chemicals with a profile low toxicity in (sub)acute tests there is little added value to conduct 90-day repeated dose study. Avoiding unnecessary animal testing central aim REACH legislation; therefore we sought verify using additional data. The OECD's eChemPortal was searched substances had both 28-day and study their robust summaries were then examined from ECHA CHEM database. Out 182...
We report the measurement of impulsive stimulated x-ray Raman scattering in neutral liquid water. An attosecond pulse drives excitations an electronic wavepacket water molecules. The process comprises two steps: a transition to core-excited states near oxygen atoms accompanied by valence-excited states. Thus, is impulsively created at specific atomic site within few hundred attoseconds through nonlinear interaction between and pulse. observe this signature intensity-dependent Stokes sideband...
Ultrafast laser pulses generated at the attosecond timescale represent a unique tool to explore fastest dynamics in matter. An accurate control of their properties, such as polarization, is fundamental shape three-dimensional laser-driven dynamics. We introduce technique generate pulse trains whose polarization state varies from pulse. This accomplished by driving high-harmonic generation with two time-delayed bichromatic counter-rotating fields proper orbital angular momentum (OAM) content....
Distinguishing between the left- and right-handed versions of a chiral molecule (enantiomers) is vital, but also inherently difficult. Traditional optical methods using elliptically/circularly polarized light rely on linear effects which arise beyond electric-dipole approximation, posing major limitations for ultrafast spectroscopy. Here we show how to turn an ultrashort elliptical pulse into efficient chiro-optical tool: by tilting its polarization plane towards propagation direction. This...
Ultrashort laser pulses pose unique tools to trigger and probe the fastest charge dynamics in matter, allowing investigation of fundamental physical phenomena with unprecedented resolution space, time, energy. One most fascinating opportunities that ultrashort offer is possibility modulating investigating symmetries by tailoring properties beam spatial polarization domains, effectively controlling symmetry breaking on multiple levels. In particular, this allows probing chiral matter...
We bring together the advantages of terahertz (THz) and optical spectroscopies to introduce TACOS (Terahertz-Assisted Chiro-Optical Spectroscopy), a novel approach for ultrafast highly efficient imaging molecular chirality control over chiral electronic dynamics. show how, using THz pulse, we can induce transient orientation in medium randomly oriented molecules that breaks isotropy sample. This symmetry breaking twists nonlinear response an ultrashort linearly polarised pulse...
Light beams with self-torque –a temporal variation of their orbital angular momentum– are described and produced for the first time. This new property light is naturally mapped onto extreme-ultraviolet waveforms via high-harmonic generation.
Abstract Synthetic chiral light enables ultrafast and highly efficient imaging of molecular chirality. Unlike standard circularly polarized light, the handedness synthetic does not rely on spatial structure field: it is encoded locally , in trajectory that tip electric-field vector draws time, at each point space. both globally (Ayuso et al 2019 Nat. Photon. 13 866) allows us to selectively quench nonlinear response a selected enantiomer while maximizing its mirror twin level total signal...
Abstract We demonstrate that the standard picture of strong-field tunnel-ionization from molecules should be reformulated. The extended nature molecular potential implies separation some sites edge ionization barrier. show dependence tunnel probability with distance to barrier is translated into ionized wavepacket, modifying substantially high-order harmonic emission. introduction site significantly improves theoretical description generation in molecules, which used as a cornerstone...