Giovanni Batignani
Research Fellow
Physics Department
"Sapienza" University
P.zzale Aldo Moro 5, Roma, Italy
Edificio "E. Fermi"
Position

Research Activities

TagCloud

My Science Cloud

My research interest is Time-Resolved Vibrational Spectroscopy, applied to access ultrafast structural and dynamical properties at the molecular and condensed matter levels.

While the foundations of the atomic structure theory go back to more than a century ago, only in the recent decades the development of novel microscopy techniques have succeeded in acquiring “photographs” of molecular compounds, with atomic structural resolution. “Animating” these static pictures to monitor the atomic motions during the primary processes that govern physical, chemical and biological phenomena, carrying out a real molecular movie, is nowadays one of the greatest scientific challenges. Recording transient atomic motions in action would allow to unveil, for example, the mechanisms ruling phase transition processes in physics and to disclose bond breaking and recombination events in biochemistry. At the microscopic level, since the speed of atomic motion is ≈ 1 km s-1, the capability of measuring structural changes of reacting species over the atomic scale (a few ångström) on timescales short enough to resolve the reaction pathways requires ≈ 100 fs “exposure times”.

The impressive technological improvements in the last years, especially the advent of bright femtosecond laser sources, paved the way to a direct exploration of these temporal realms and have been foundational to ultrafast spectroscopy, in which light pulses are used to first excite (Pump) and subsequently interrogate (Probe) a system. Critically, the natural hindrance in this field revolves around the simultaneous need of two key ingredients: high temporal and spectral resolutions, which are mutually compromised due to the Heisenberg principle. Ultrafast electronic spectroscopies offer femtosecond time resolution, but cannot provide detailed information on the geometrical configuration of the system, due to the lack of structural sensitivity. On the other hand, vibrational spectroscopies, used to study molecular and solid state compounds, provide excellent spatial resolution but are ineffective on subpicosecond timescales.

In this respect, my work focuses on the development of experimental, conceptual and numerical protocls able to circumvent restrictions dictated by the Heisenberg principle for unravelling matter properties on picosecond and sub-picosecond time regimes. The main idea is to exploit Coherent Raman Spectroscopy for combining the structural sensitivity of vibrational specroscopy with the temporal resolution that can be achieved in Non-Linear Spectroscopy investigating a system of interest with multiple light pulses.


Highlights

Mapping the interactions between vibrational and electronic molecular excitations by 2D Raman spectroscopy.

Light-induced processes in molecules rely on the efficient and directed conversion of photon energy into electronic and atomic motions. This conversion is controlled by the underlying multidimensional energy surfaces, which describe how the potential energy of the system changes with modifications in the vibrational and electronic configurations. Mapping the potentianl energy surfaces over multiple vibrational dimensions discloses the ultrafast evolution of the system but is typically hampered by the need of spectroscopic probes detecting different energy scales with high temporal and frequency resolution. Two-Dimensional (2D) coherent Raman spectroscopy, by exploiting three temporally delayed femtosecond pulses to coherently generate and track excited-state vibrational wavepackets, is able to probe vibrational correlations pertaining to a targeted electronically excited state. The evolution of the wavepackets is determined by the shapes of the vibrationally structured potential energy surfaces of the system. Couplings and correlations appear as cross peaks in 2D Raman maps, whose origin can be assigned by using a diagrammatic perturbative expansion in terms of the field-matter interactions, mapping the multidimensional energy surfaces.

Article: Physical Review X (2020).

Atomic scale Truman show: making molecular movies of reacting proteins.

Identifying the structural rearrangement and the active sites in photo-induced reactions is a fundamental challenge to understand from a microscopic perspective the ultrafast dynamics of heme proteins. Among the different types of hemes, those able to form the iron atom sixth bond with an internal residue, namely six-coordinate hemes, represent one of the most elusive systems for ultrafast spectroscopies. As dissociation of the internal residue is followed by a rapid rebinding embedded with several picosecond and femtosecond concurring processes, such as structural reconfiguration, energy redistribution and relaxation on intermediate excited states, the natural hindrance for their study revolves around the simultaneous need of two key ingredients: high temporal and spectral resolutions, which are mutually compromised due to the Heisenberg principle. By exploiting femtosecond stimulated Raman spectroscopy (FSRS) to follow the ultrafast evolution of different six-coordinate hemes with combined high spectral resolution and femtosecond time precision, we have determined the whole spectrum of vibrational amplitudes with extremely high temporal resolution, allowing us to animate the molecular normal modes and to visualize how the different structural and thermal relaxation processes syncretize on the coherent picture of the reaction pathway.

Article: Journal of the American Chemical Society (2020).
Video: Molecular movie of a photoexcited heme.

International School On Nonlinear Vibrational Spectro-microscopy.

An International sChool On Nonlinear vibrational Spectro-microscopy (ICONS) will be held at the Physics Department of "Sapienza" University of Rome, July 30th-August 1st 2020. ICONS will be structured around comprehensive review talks from major world leading experts in complementary areas of nonlinear Raman spectroscopy both on theory, experiments and applications. The aim of the school is to provide high level-expertise for young researchers, graduate students interested in nonlinear Raman spectroscopy, applied to access dynamical and microscopic properties at the molecular and condensed matter levels. Specifically, the school will be three days of classes, with an introduction on the peculiarities of nonlinear Raman approaches with respect to linear Raman spectroscopy, discussing the technical requirements and the main tools that are conventionally exploited in modern experimental laboratories to manipulate and control optical pulses. The following two days will be focused on time-resolved and microscopic techniques, with principles and examples. The program, supported by world leading experts in the field of Raman nonlinear photonics, aims to have a balance between theoretical and experimental advances.

More info: ICONS Webpage (2020).
Organizers: Giovanni Batignani & Carino Ferrante.

Exploiting Long pulses to probe Short phenomena.

Impulsive stimulated Raman scattering (ISRS) is a powerful technique able to real time monitor vibrational oscillations in photo-excited systems: by combining a pump and a probe pulse for stimulating and then probing Raman coherences, ISRS can directly access atomic motions and molecular properties. Critically, at odd with frequency-domain Raman approaches, ISRS typically requires long acquisition times since the system response has to be measured scanning a sequence of time delays between pump and probe pulses. Introducing a chirp in the probe pulse, we have introduced a novel experimental scheme for the realization of Chirped-based ISRS (CISRS), for recording the time-domain Raman information without scanning the pump and probe delay: since different probe wavelengths interact with sample at different time delays, the evolution of the stimulated vibrational coherences is encoded in the probe spectrum.

Article: J. Phys. Chem. Lett., arXiv (2019).
Video(s): Part 1, ISRS in a nutshell; Part 2, Turning ISRS into CISRS.

Negative photo of graphene flakes by Cohenrent Raman Spectroscopy.

Spontaneous Raman spectroscopy is a powerful characterization tool for graphene research. Its extension to the coherent regime, despite the large nonlinear third-order susceptibility of graphene, has so far proven challenging. Due to its gapless nature, several interfering electronic and phononic transitions concur to generate its optical response, preventing to retrieve spectral profiles analogous to those of spontaneous Raman. We have recently reported stimulated Raman spectroscopy of the G-phonon in single and multi-layer graphene, through coherent anti-Stokes Raman Scattering (CARS). The nonlinear signal is dominated by a vibrationally non-resonant background, obscuring the Raman lineshape. We demonstrate that the vibrationally resonant coherent anti-Stokes Raman Scattering peak can be measured by reducing the temporal overlap of the laser excitation pulses, suppressing the vibrationally non-resonant background. Modelling the spectra, for taking into account the electronically resonant nature of both, we have shown how CARS can be used for graphene imaging with vibrational sensitivity.

Article: Nature Communications (2019).
Video: Coherent anti-Astokes Raman scattering of graphene samples.

Manipulating magnetic properties with femtosecond laser pulses.

Raman techniques are pivotal in many interdisciplinary aspects of photonics. In this work we use, in turn, fundamentals of non-linear photonics as a key enabling tools to disclose sub-100 fs magnetic excitations dynamics exploiting coherent Raman spectroscopy. The relevance of probing the ultrafast dynamics of the exchange interaction strikes a chord of interest from both the fundamental and applied science standpoint. On the one hand one wonders on how fast angular momentum can be exchanged, and if it may become possible to reach the timescale of the spin-orbit interaction. On the other hand, the study of the fundamental and practical limits of the speed of manipulation of the magnetic ordering is obviously of great importance for magnetic recording and information processing technologies.

Article(s): Annalen Der Physik (2019), Nature Photonics (2015).


Articles

2013 2014 2015 2016 2017 2018 2019 2020

Published       Accepted       Submitted      

2020

Accessing Excited State Molecular Vibrations by Femtosecond Stimulated Raman Spectroscopy.
    G. Batignani, C. Ferrante and T. Scopigno.
    Submitted, (2020)

Ultrafast dynamics and vibrational relaxation in six-coordinate heme proteins revealed by Femtosecond Stimulated Raman Spectroscopy.
    C. Ferrante, G. Batignani, E. Pontecorvo, L.C. Montemiglio, M. H. Vos and T. Scopigno.
    Journal of the American Chemical Society, 142, 2285, (2020)

Two-dimensional impulsively stimulated resonant Raman spectroscopy of molecular excited-states.
    G. Fumero, C. Schnedermann, G. Batignani, T. Wende, M. Liebel, G. Bassolino, C. Ferrante, S. Mukamel, P. Kukura, T. Scopigno.
    Physical Review X, 10, 011051, (2020)

2019

Broadband Impulsive Stimulated Raman Scattering based on a Chirped Detection.
    G. Batignani, C. Ferrante, G. Fumero and T. Scopigno.
    The Journal of Physical Chemistry Letters, 10, 7789, (2019)

Modeling the ultrafast response of two-magnon Raman excitations in antiferromagnets on the femtosecond timescale.
    G. Batignani, E. Pontecorvo, D. Bossini, C. Ferrante, G. Fumero, G. Cerullo, S. Mukamel and T. Scopigno.
    Annalen der Physik, 1900439, (2019)

Coherent anti-Stokes Raman Spectroscopy of single and multi-layer graphene.
    A. Virga, C. Ferrante, G. Batignani, D. De Fazio, A. D. Nunn, A. C. Ferrari, G. Cerullo, T. Scopigno.
    Nature Communications, 10, 3658, (2019)

Genuine dynamics vs cross phase modulation artefacts in Femtosecond Stimulated Raman Spectroscopy.
    G. Batignani, G. Fumero, E. Pontecorvo, C. Ferrante, S. Mukamel, T. Scopigno.
    ACS Photonics, 6, 492, (2019)

The Potential of EuPRAXIA@SPARC_LAB for Radiation Based Techniques.
    A. Balerna, S. Bartocci, G. Batignani et al.
    Condensed Matter, 4, 30, (2019)

2018

Probing Femtosecond Lattice Displacement upon Photo-carrier generation in Lead Halide Perovskite.
    G. Batignani, G. Fumero, A. R. S. Kandada, G. Cerullo, M. Gandini, C. Ferrante, A. Petrozza, T. Scopigno.
    Nature Communications, 9, 1971, (2018)

Resonant Broadband Stimulated Raman scattering in Myoglobin.
    C. Ferrante, G. Batignani, G. Fumero, E. Pontecorvo, A. Virga, L. C. Montemiglio, G. Cerullo, M. H. Vos, T. Scopigno.
    Journal of Raman Spectroscopy, 1-8, (2018)

2017

Manipulating impulsive stimulated Raman spectroscopy with a chirped probe pulse.
    L. Monacelli, G. Batignani, G. Fumero, C. Ferrante, S. Mukamel and T. Scopigno.
    The Journal of Physical Chemistry Letters, 8, 966, (2017)

2016

Visualizing excited-state dynamics of a diaryl thiophene: femtosecond stimulated Raman scattering as a probe of conjugated molecules.
    G. Batignani, E. Pontecorvo, C. Ferrante, M. Aschi, C.G. Elles and T. Scopigno.
    The Journal of Physical Chemistry Letters, 7, 2981, (2016)

Probing ultrafast processes by fifth order Stimulated Raman Scattering.
    G. Fumero, G. Batignani, K. E. Dorfman, S. Mukamel and T. Scopigno.
    Journal of Physics: Conference Series, 689, 012023, (2016)

Probing ultrafast photo-induced dynamics of the exchange energy in a Heisenberg antiferromagnet.
    G. Batignani, D. Bossini, N. Di Palo, C. Ferrante, E. Pontecorvo, G. Cerullo, A. Kimel and T. Scopigno.
    OSA Technical Digest, http://dx.doi.org/10.1364/UP-2016-UTh3A.7, (2016)

Broadband Stimulated Raman spectroscopy in electronically resonant biomolecules.
    G. Batignani, E. Pontecorvo, G. Giovannetti, C. Ferrante, G. Fumero and T. Scopigno.
    Scientific Reports, 6, 18445, (2016)

2015

On the resolution limit of Femtosecond Stimulated Raman Spectroscopy: modelling fifth-order signals with overlapping pulses.
    G. Fumero, G. Batignani, K. E. Dorfman, S. Mukamel and T. Scopigno.
    Chem. Phys. Chem., 16, 3438, (2015)

Probing ultrafast photoinduced dynamics of the exchange energy in an Heisenberg antiferromagnet.
    G. Batignani, D. Bossini, N. Di Palo, C. Ferrante, E. Pontecorvo, G. Cerullo, A. Kimel and T. Scopigno.
    Nature Photonics, 9, 506, (2015)

Energy flow between spectral components in 2D Broadband Stimulated Raman Spectroscopy.
    G. Batignani, G. Fumero, S. Mukamel and T. Scopigno.
    Physical Chemistry Chemical Physics, 17, 10454, (2015)

2014

Snapshots of sub-ps dynamics in heme-proteins captured by Femtosecond Stimulated Raman Scattering.
    T. Scopigno, C. Ferrante, E. Potecorvo, G. Batignani.
    OSA Technical Digest, http://dx.doi.org/10.1364/UP.2014.11.Fri.A.6, (2014)

2013

Detection of excited level population transfer in an MOT through the measurement of trapped atom number.
    L. Moi, G. Batignani, A. Khanbekyan et al.
    Measurement Science and Technology , 24, 015201, (2014)


Teaching

Academic Year 2019/2020

CORSO DI LAUREA TRIENNALE: “OTTICA E LABORATORIO”
Laurea Triennale in Fisica
Dipartimento di Fisica, Sapienza Università di Roma
Pagina Web del Corso.


Thesis

MASTER THESIS


Presso i Laboratory Femtoscopy sono disponibili dissertazioni magistrali su:


DISSERTAZIONI

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Contacts

Mail: giovanni.batignani[at]uniroma1.it
Address: Piazzale Aldo Moro 5, Roma, 00185, Italy
Office: Edificio "E. Fermi", Room 508
Office hours: any time (if I am free).
Phone (office): 0649913478
Phone (lab):