Matteo Negro - Academia.edu (original) (raw)

Papers by Matteo Negro

APL photonics, Nov 1, 2022

EPJ Web of Conferences

We demonstrate the generation of high-order harmonics in a fused-silica device fabricated through... more We demonstrate the generation of high-order harmonics in a fused-silica device fabricated through femtosecond laser micromachining. This achievement paves the way for the miniaturization of HHG applications from large-scale laboratories to microstructures.

Physical chemistry chemical physics : PCCP, Jan 31, 2017

We demonstrate the experimental realization of impulsive alignment of carbonyl sulfide (OCS) mole... more We demonstrate the experimental realization of impulsive alignment of carbonyl sulfide (OCS) molecules at the Low Density Matter Beamline (LDM) at the free-electron laser FERMI. OCS molecules in a molecular beam were impulsively aligned using 200 fs pulses from a near-infrared laser. The alignment was probed through time-delayed ionization above the sulphur 2p edge, resulting in multiple ionization via Auger decay and subsequent Coulomb explosion of the molecules. The ionic fragments were collected using a time-of-flight mass spectrometer and the analysis of ion-ion covariance maps confirmed the correlation between fragments after Coulomb explosion. The analysis of the CO(+) and S(+) channels allowed us to extract the rotational dynamics, which is in agreement with our theoretical description as well as with previous experiments. This result opens the way for a new class of experiments at LDM within the field of coherent control of molecules with the possibilities that a precisely s...

International Conference on Ultrafast Phenomena, 2016

Frontiers in Optics 2010/Laser Science XXVI, 2010

ABSTRACT We exploited a few-cycle, carrier-envelope-phase-stabilized IR parametric source for spe... more ABSTRACT We exploited a few-cycle, carrier-envelope-phase-stabilized IR parametric source for spectral extension of high-harmonics emission. We studied HOMO-related structures in HHG form impulsively aligned CO2. We generated broadband continua above 150 eV in a two-color scheme.

Springer Series in Optical Sciences, 2015

Journal of Physics B: Atomic, Molecular and Optical Physics, 2014

High-harmonics generation spectroscopy is a promising tool for resolving electron dynamics and st... more High-harmonics generation spectroscopy is a promising tool for resolving electron dynamics and structure in atomic and molecular systems. This scheme, commonly described by the strong field approximation, requires a deep insight into the basic mechanism that leads to the harmonics generation. Recently, we have demonstrated the ability to resolve the first stage of the process-field induced tunnel ionization-by adding a weak perturbation to the strong fundamental field. Here we generalize this approach and show that the assumptions behind the strong field approximation are valid over a wide range of tunnel ionization conditions. Performing a systematic study-modifying the fundamental wavelength, intensity and atomic system-we observed a good agreement with quantum path analysis over a range of Keldysh parameters. The generality of this scheme opens new perspectives in high harmonics spectroscopy, holding the potential of probing large, complex molecular systems.

2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011

Abstract Ultrafast birefringence induced by filamentation-based rotational excitation in Nitrogen... more Abstract Ultrafast birefringence induced by filamentation-based rotational excitation in Nitrogen is exploited to modulate the polarization state of a probe pulse. This modulation is effectively employed for controlling high-order harmonic generation in Argon.

Frontiers in Optics 2012/Laser Science XXVIII, 2012

Faraday discussions, 2014

High-order harmonic generation is a powerful and sensitive tool for probing atomic and molecular ... more High-order harmonic generation is a powerful and sensitive tool for probing atomic and molecular structures, combining in the same measurement an unprecedented attosecond temporal resolution with a high spatial resolution of the order of an angstrom. Imaging of the outermost molecular orbital by high-order harmonic generation has been limited for a long time to very simple molecules, like nitrogen. Recently we demonstrated a technique that overcame several of the issues that have prevented the extension of molecular orbital tomography to more complex species, showing that molecular imaging can be applied to a triatomic molecule like carbon dioxide. Here we report on the application of such a technique to nitrous oxide (N(2)O) and acetylene (C(2)H(2)). This result represents a first step towards the imaging of fragile compounds, a category which includes most of the fundamental biological molecules.

Optics Express, 2014

High order harmonic generation (HHG) has shown its impact on several applications in Attosecond S... more High order harmonic generation (HHG) has shown its impact on several applications in Attosecond Science and Atomic and Molecular Physics. Owing to the complexity of the experimental setup for the generation and characterization of harmonics, as well as to the large computational costs of numerical modelling, HHG is generally performed and modelled in collinear geometry. Recently, several experiments have been performed exploiting non-collinear geometry, such as HHG in a grating of excited molecules created by crossing beams. In such studies, harmonics were observed at propagation directions different from those of the driving pulses; moreover the scattered harmonics were angularly dispersed. In this work we report on a new regime of HHG driven by multiple beams, where the harmonics are generated by three synchronized, intense laser pulses organized in a non-planar geometry. Although the configuration we explore is well within the strong-field regime, the scattered harmonics we observe are not angularly dispersed.

2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT We studied the two-color HHG emission from xenon in the giant resonance spectral region.... more ABSTRACT We studied the two-color HHG emission from xenon in the giant resonance spectral region. We found a substantial departure from the behavior expected for the single-active-electron picture which could be ascribed to electron correlation effects.

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT Extending the dimensionality of high harmonic generation (HHG) measurements has the pote... more ABSTRACT Extending the dimensionality of high harmonic generation (HHG) measurements has the potential to reconstruct structural features in molecules and resolve multielectron dynamics on attosecond time scales. We demonstrate that structural and dynamical effects in molecules can be unambiguously distinguished using multidimensional HHG techniques.

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT Intense, few-cycle infrared laser pulses centered at 1.8 µm wavelength, coupled to a new... more ABSTRACT Intense, few-cycle infrared laser pulses centered at 1.8 µm wavelength, coupled to a new gas cell design, are employed to drive high harmonic generation with high flux down to the soft X-ray regime.

International Conference on Ultrafast Phenomena, 2010

... [3] P. Tzallas, E. Skantzakis, C. Kalpouzos, EP Benis, GD Tsakiris and D. Charalambidis, Nat.... more ... [3] P. Tzallas, E. Skantzakis, C. Kalpouzos, EP Benis, GD Tsakiris and D. Charalambidis, Nat. Phys. 3, 846 (2007). [4] X. Feng, S. Gilbertson, H. Mashiko, H. Wang, SD Khan, M. Chini, Y. Wu, K. Zhao, and Z. Chang, Phys. Rev. Lett. 103, 183901 (2009). ...

International Conference on Ultrafast Phenomena, 2010

ABSTRACT High order harmonics driven by an ultrafast IR parametric source were generated in align... more ABSTRACT High order harmonics driven by an ultrafast IR parametric source were generated in aligned CO2; the experimental results present a clear spectral minimum related to the HOMO structure.

We investigated the generation of XUV high order harmonics in gases by two-color driving pulses, ... more We investigated the generation of XUV high order harmonics in gases by two-color driving pulses, exploiting an infrared parametric source with self-stabilization of the carrier-envelope phase. Continuous XUV spectra were generated, showing a spectral extension beyond 100 eV. These results represent a step forward in the extension of attosecond science towards the soft-X rays region.

APL photonics, Nov 1, 2022

EPJ Web of Conferences

We demonstrate the generation of high-order harmonics in a fused-silica device fabricated through... more We demonstrate the generation of high-order harmonics in a fused-silica device fabricated through femtosecond laser micromachining. This achievement paves the way for the miniaturization of HHG applications from large-scale laboratories to microstructures.

Physical chemistry chemical physics : PCCP, Jan 31, 2017

We demonstrate the experimental realization of impulsive alignment of carbonyl sulfide (OCS) mole... more We demonstrate the experimental realization of impulsive alignment of carbonyl sulfide (OCS) molecules at the Low Density Matter Beamline (LDM) at the free-electron laser FERMI. OCS molecules in a molecular beam were impulsively aligned using 200 fs pulses from a near-infrared laser. The alignment was probed through time-delayed ionization above the sulphur 2p edge, resulting in multiple ionization via Auger decay and subsequent Coulomb explosion of the molecules. The ionic fragments were collected using a time-of-flight mass spectrometer and the analysis of ion-ion covariance maps confirmed the correlation between fragments after Coulomb explosion. The analysis of the CO(+) and S(+) channels allowed us to extract the rotational dynamics, which is in agreement with our theoretical description as well as with previous experiments. This result opens the way for a new class of experiments at LDM within the field of coherent control of molecules with the possibilities that a precisely s...

International Conference on Ultrafast Phenomena, 2016

Frontiers in Optics 2010/Laser Science XXVI, 2010

ABSTRACT We exploited a few-cycle, carrier-envelope-phase-stabilized IR parametric source for spe... more ABSTRACT We exploited a few-cycle, carrier-envelope-phase-stabilized IR parametric source for spectral extension of high-harmonics emission. We studied HOMO-related structures in HHG form impulsively aligned CO2. We generated broadband continua above 150 eV in a two-color scheme.

Springer Series in Optical Sciences, 2015

Journal of Physics B: Atomic, Molecular and Optical Physics, 2014

High-harmonics generation spectroscopy is a promising tool for resolving electron dynamics and st... more High-harmonics generation spectroscopy is a promising tool for resolving electron dynamics and structure in atomic and molecular systems. This scheme, commonly described by the strong field approximation, requires a deep insight into the basic mechanism that leads to the harmonics generation. Recently, we have demonstrated the ability to resolve the first stage of the process-field induced tunnel ionization-by adding a weak perturbation to the strong fundamental field. Here we generalize this approach and show that the assumptions behind the strong field approximation are valid over a wide range of tunnel ionization conditions. Performing a systematic study-modifying the fundamental wavelength, intensity and atomic system-we observed a good agreement with quantum path analysis over a range of Keldysh parameters. The generality of this scheme opens new perspectives in high harmonics spectroscopy, holding the potential of probing large, complex molecular systems.

2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011

Abstract Ultrafast birefringence induced by filamentation-based rotational excitation in Nitrogen... more Abstract Ultrafast birefringence induced by filamentation-based rotational excitation in Nitrogen is exploited to modulate the polarization state of a probe pulse. This modulation is effectively employed for controlling high-order harmonic generation in Argon.

Frontiers in Optics 2012/Laser Science XXVIII, 2012

Faraday discussions, 2014

High-order harmonic generation is a powerful and sensitive tool for probing atomic and molecular ... more High-order harmonic generation is a powerful and sensitive tool for probing atomic and molecular structures, combining in the same measurement an unprecedented attosecond temporal resolution with a high spatial resolution of the order of an angstrom. Imaging of the outermost molecular orbital by high-order harmonic generation has been limited for a long time to very simple molecules, like nitrogen. Recently we demonstrated a technique that overcame several of the issues that have prevented the extension of molecular orbital tomography to more complex species, showing that molecular imaging can be applied to a triatomic molecule like carbon dioxide. Here we report on the application of such a technique to nitrous oxide (N(2)O) and acetylene (C(2)H(2)). This result represents a first step towards the imaging of fragile compounds, a category which includes most of the fundamental biological molecules.

Optics Express, 2014

High order harmonic generation (HHG) has shown its impact on several applications in Attosecond S... more High order harmonic generation (HHG) has shown its impact on several applications in Attosecond Science and Atomic and Molecular Physics. Owing to the complexity of the experimental setup for the generation and characterization of harmonics, as well as to the large computational costs of numerical modelling, HHG is generally performed and modelled in collinear geometry. Recently, several experiments have been performed exploiting non-collinear geometry, such as HHG in a grating of excited molecules created by crossing beams. In such studies, harmonics were observed at propagation directions different from those of the driving pulses; moreover the scattered harmonics were angularly dispersed. In this work we report on a new regime of HHG driven by multiple beams, where the harmonics are generated by three synchronized, intense laser pulses organized in a non-planar geometry. Although the configuration we explore is well within the strong-field regime, the scattered harmonics we observe are not angularly dispersed.

2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC, 2013

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT We studied the two-color HHG emission from xenon in the giant resonance spectral region.... more ABSTRACT We studied the two-color HHG emission from xenon in the giant resonance spectral region. We found a substantial departure from the behavior expected for the single-active-electron picture which could be ascribed to electron correlation effects.

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT Extending the dimensionality of high harmonic generation (HHG) measurements has the pote... more ABSTRACT Extending the dimensionality of high harmonic generation (HHG) measurements has the potential to reconstruct structural features in molecules and resolve multielectron dynamics on attosecond time scales. We demonstrate that structural and dynamical effects in molecules can be unambiguously distinguished using multidimensional HHG techniques.

19th International Conference on Ultrafast Phenomena, 2014

ABSTRACT Intense, few-cycle infrared laser pulses centered at 1.8 µm wavelength, coupled to a new... more ABSTRACT Intense, few-cycle infrared laser pulses centered at 1.8 µm wavelength, coupled to a new gas cell design, are employed to drive high harmonic generation with high flux down to the soft X-ray regime.

International Conference on Ultrafast Phenomena, 2010

... [3] P. Tzallas, E. Skantzakis, C. Kalpouzos, EP Benis, GD Tsakiris and D. Charalambidis, Nat.... more ... [3] P. Tzallas, E. Skantzakis, C. Kalpouzos, EP Benis, GD Tsakiris and D. Charalambidis, Nat. Phys. 3, 846 (2007). [4] X. Feng, S. Gilbertson, H. Mashiko, H. Wang, SD Khan, M. Chini, Y. Wu, K. Zhao, and Z. Chang, Phys. Rev. Lett. 103, 183901 (2009). ...

International Conference on Ultrafast Phenomena, 2010

ABSTRACT High order harmonics driven by an ultrafast IR parametric source were generated in align... more ABSTRACT High order harmonics driven by an ultrafast IR parametric source were generated in aligned CO2; the experimental results present a clear spectral minimum related to the HOMO structure.

We investigated the generation of XUV high order harmonics in gases by two-color driving pulses, ... more We investigated the generation of XUV high order harmonics in gases by two-color driving pulses, exploiting an infrared parametric source with self-stabilization of the carrier-envelope phase. Continuous XUV spectra were generated, showing a spectral extension beyond 100 eV. These results represent a step forward in the extension of attosecond science towards the soft-X rays region.