Latest News | L2I team

Gonçalo Almeida successfully defends MSc thesis

Wed, 10 Dec 2025 00:00:00 +0000

Gonçalo P. Almeida (second from the left), visiting researcher at L2I, successfully defended his MSc thesis titled ‘Optical signal characterisation in Laser-Induced Breakdown Spectroscopy’. Gonçalo was supervised by our GoLP colleague Prof. João M. Dias (left). The thesis panel also included L2I members Hugo Pires (second from the right) and Gonçalo Figueira (right).

In his work, he characterised the plasma optical emission under the influence of varying experimental conditions, by studying their effect on signal intensity and measurement variability. A dedicated test bench was assembled at L2I and the ultrashort Amphos laser system was used as the pulsed light source.

The main results showed that, for ultrashort pulse durations and fluences below 22±6 J/cm2, the signal intensity varies linearly with the pulse energy. The analysis also revealed the existence of two maxima, and a slight defocus was shown to improve plasma generation.

Concerning signal collection, an optimal magnification that maximizes the collected emission was found. Additionally, the impact of the chromatic focal shift was verified and the isotropic nature of the plasma emission was demonstrated.

Congratulations, Gonçalo!

Hugo Pires and Gonçalo Vaz attend UFO2025

Tue, 14 Oct 2025 00:00:00 +0000

The Ultrafast Optics XIV conference took place between Oct 5 and Oct 10, in the Azores, Portugal.

Hugo Pires and Gonçalo Vaz presented our latest results at this conference:

Nonlinear characterization of materials via low order surface harmonics driven by 100 fs pulses operating at 100 kHz, H. Pires , H. Gomes, G. Vaz, G. Figueira, and A. G. Silva
High-contrast broadband seed generation for Vulcan 20-20, G. Vaz, P. Oliveira, H. Crespo, H. Pires
Few-cycle, mJ-level 3 µm source driven by 1030 nm pulses, G. Vaz, H. Pires, G. Figueira

Funding awarded for renovation of laser diagnostics

Mon, 10 Feb 2025 00:00:00 +0000

L2I is part of the Técnico Flagship Labs proposal, a consortium bringing together several research and teaching laboratories at Instituto Superior Técnico (IST), which has been awarded €4 million for the period from July 2024 to July 2027. This was the highest amount granted in the competition.

The funding is provided by the Lisbon and Tagus Valley Regional Coordination and Development Commission (CCDR-LVT) under its programme for scientific infrastructures and will be co-funded by IST, bringing the total investment to €10 million.

Within this framework, L2I will receive close to €400,000. This funding will be primarily invested in the replacement of essential infrastructure, such as the air treatment unit, as well as in the acquisition of advanced pulse and beam diagnostics, and specialised optical and optomechanical components.

To know more: Técnico will renovate and create dozens of laboratories dedicated to research, training and knowledge transfer

Miguel Mendes completes his MSc in Physics Engineering

Thu, 05 Dec 2024 00:00:00 +0000

Miguel Mendes (second from the left) successfully defended his MSc thesis in Physics Engineering entitled “Second -order couplings in ultrashort pulses with cylindrical symmetry” on December 5, 2024. He was supervised by Gonçalo Figueira (left).

During his work, Miguel investigated second-order spatiotemporal couplings in ultrashort pulses, a phenomenon that becomes relevant for few-cycle pulses and that has attracted growing attention in recent years.

He developed a numerical code for visualizing and propagating laser pulses with this type of coupling and investigated how their intensity and instantaneous colour change with propagation. The code was then successfully applied to study pulses exhibiting pulse front curvature, radial chirp and other distortions.

The MSc jury, consisting of Marco Piccardo, Jorge Vieira and Marta Fajardo (from the center to right), highlighted the development of the new simulation tool and the challenging nature of the problem studied, and awarded a final grade of 18/20.

The thesis was Miguel’s last step in concluding his MSc in Physics Engineering at IST. Congratulations!

Thomas Südmeyer visit

Mon, 25 Nov 2024 00:00:00 +0000

Last November 21 we had the pleasure of hosting Thomas Südmeyer, Director of the Time and Frequency Laboratory at the Physics Department of the Université de Neuchâtel, for a lab tour and discussion.

Prof. Südmeyer is a renowned specialist in photonics, metrology, and ultrashort pulse science. He has coordinated several Swiss and European projects, is the recipient of an ERC Starting Grant, and served as an Associate Editor for Optics Express (2009–2015) and IEEE Photonics Technology Letters (2014–2017). We had an interesting conversation about current perspectives, trends and opportunities in our common research in ultrafast laser science.

Íñigo Sola visit

Mon, 24 Jun 2024 00:00:00 +0000

Last June 21 our team had the pleasure of hosting Íñigo Sola for a lab tour and seminar. Íñigo is a Full Professor at the Applied Physics Department of the University of Salamanca and a researcher at the ALF-USAL group.

In his talk he discussed both research and academic activities at the University of Salamanca, covering areas such as ultrafast laser technology, nonlinear light-matter interaction, attoscience, and laser processing applications. He presented USAL’s Master in Laser Science and Technology and we exchanged many interesting ideas both in teaching and research.

(Pictured: Gonçalo Figueira, Marta Fajardo, Íñigo and Hugo Pires)

Joana Alves successfully defends Ph.D. thesis

Sat, 23 Sep 2023 00:00:00 +0000

Joana Alves successfully defended her PhD thesis entitled “Ultrafast mid-infrared unable sources” on September 19, 2023. Her work was supervised by Gonçalo Figueira, Hugo Pires (both at IPFN/IST) and Jens Biegert (ICFO, Spain).

During her Ph.D. in the scope of the APPLAuSE programme, Joana specialised in the study of ultrafast mid-infrared (3-8 µm) laser technology, in particular nonlinear amplification of ultrashort pulses through OPCPA and their compression.

She evaluated strategies for achieving few-cycle, millijoule-level pulses in this wavelength region, working with three different laser systems, at the Laboratory for Intense Lasers, IST and at the Attosecond and Ultrafast Optics group at ICFO. One of the main results is the implementation study of a new ultrafast (5-optical-cycles), high energy (5 mJ), 3 μm laser system and an analysis of the main challenges for compressing pulses at this wavelength range.

The PhD jury, consisting of Greg Greetham (STFC, UK), Olivier Chalus (Thales, France), Ana G. Silva (FCT-UNL, Portugal), Gareth Williams (IPFN/IST), Gonçalo Figueira and Luís L. Alves (both Phys. Dept. IST), unanimously highlighted the significant amount of effort, the quality and the high impact of her achievements.

Congratulations, Joana!

New paper in Optics Express

Thu, 01 Jun 2023 00:00:00 +0000

Our most recent work on spectral broadening in multipass cells was now published in Optics Express, with my former PhD student (now Dr.) Victor Hariton as the first author and main driving force behind this idea, together with collaborators K. Fritsch, K. Schwarz, N. Kovalenko, G. Arisholm and O. Pronin.

In this work, we introduce a novel multi-pass convex-concave arrangement, which exhibits crucial properties such as large mode size and compactness. In a proof-of-principle experiment, 260 fs, 15 µJ and 200 µJ pulses are broadened and subsequently compressed to approximately 50 fs with 90% efficiency and excellent spatio-spectral homogeneity across the beam profile. We simulate the proposed concept for spectral broadening of 40 mJ and 1.3 ps input pulses and discuss the possibility of further scaling.

To know more:

Victor Hariton, Kilian Fritsch, Kevin Schwarz, Nazar Kovalenko, Gonçalo Figueira, Gunnar Arisholm, and Oleg Pronin, Spectral broadening in convex-concave multipass cells. Opt. Express 31, 19554-19568 (2023).

Farewell to Victor

Thu, 12 Jan 2023 00:00:00 +0000

Victor Hariton has left the team and moved to star a postdoc position at the Laser Science and Technology team of DESY, in Germany,

During his stay in our team, Victor gave contributions in different fields, from femtosecond ablation with shaped pulses (for which he was awarded the Gulbenkian Stimulus to Scientific Research prize in 2017) to studies in thermal lensing in Yb-doped media, amplifier development and more recently to nonlinear spectral broadening and pulse compression in multipass cells, in collaboration with Oleg Pronin‘s team at HSU.

Best wishes to Victor!

Paper accepted in Optics Letters

Sat, 26 Feb 2022 00:00:00 +0000

Victor Hariton has just published another paper covering an important part of his PhD research, resulting from the successful collaboration with Oleg Pronin‘s team at HSU.

In this work, multipass spectral broadening and compression around 515 nm are experimentally demonstrated. A nonlinear multipass cell with a bulk medium is used to compress 250-fs pulses down to 38 fs. The same input pulses create a sufficient bandwidth for sub-20-fs pulse generation in a multipass cell with gaseous media. In both cases, the efficiency exceeds 85%. Dispersion management by reduction of the cell size and the thickness of the nonlinear medium allows an efficient generation of ultrashort pulses in the visible range and establishes a pathway for ultraviolet spectral broadening by means of multipass cells.

V. Hariton, A. Bin Wahid, G. Figueira, K. Fritsch, and O. Pronin, Multipass spectral broadening and compression in the green spectral range. Optics Letters 47, 1246-1249 (2022)

Mario Galletti awarded Best PhD Thesis in Optics and Photonics prize in Portugal, 2020

Wed, 17 Nov 2021 00:00:00 +0000

Mario Galletti has received the award for the Best PhD Thesis in Optics and Photonics in Portugal, 2020, sponsored by the Portuguese Society for Optics and Photonics – SPOF.

The thesis, with the title of “High contrast front-end for a petawatt laser system designed for electron acceleration & High-intensity laser-matter applications towards advanced compact particle accelerators” was supervised by Prof. Gonçalo Figueira (Instituto Superior Tecnico, Universidade de Lisboa) and Dr. Marco Galimberti (Central Laser Facility, Rutherford Appleton Laboratory, Oxford).

Congratulations Mario!

Paper accepted in Photonics

Tue, 09 Nov 2021 00:00:00 +0000

Our work on numerical modelling of multi-mJ scaling of few-cycle optical parametric chirped-pulse amplifier (OPCPA) at 3 µm has just been accepted for publication in MDPI Photonics.

We present a design for OPCPA and demonstrate that with a configuration of a single crystal or combination of crystals (KTA and MgO:LN) it is possible to achieve output energies above the mJ with sufficient bandwidth to allow compression to just 5-optical cycles. We consider a 1 µm mJ-level picosecond chirped-pulse amplifier (CPA), a typical pumping source for this type of nonlinear amplifiers. Compression with a simple bulk material enables reaching close to the pulse Fourier-transform limited duration, paving the way to high-energy, ultrafast mid-infrared pulses.

This work will now be pursued experimentally with the development of an upgrade to our 3 µm laser system.

J. Alves, H. Pires, C. P. João and G. Figueira, Multi-mJ Scaling of 5-Optical Cycle, 3 µm OPCPA. Photonics 8(11), 503 (2021)

Mario Galletti obtains PhD Research Award from EPS

Sun, 07 Mar 2021 00:00:00 +0000

Former team member and APPLAuSE student Mario Galletti was awarded one of the European Physical Society (EPS) Plasma Physics Division PhD Research Award for its 2021 edition. The prize recognizes truly outstanding research achievements associated with a PhD study in the broad field of plasma physics. Up to four prizes are given annually to young scientists from the 38 European countries associated with the EPS.

Mario’s thesis is entitled “High contrast front-end for a petawatt laser system designed for electron acceleration & High-intensity laser-matter applications towards advanced compact particle accelerators” and was supervised by Prof. Gonçalo Figueira (IPFN, IST) and Dr. Mario Galimberti (CLF, STFC, UK).

In his thesis, Mario investigated the generation of ultrashort laser pulses in the near-infrared region between 750 and 1000 nm, which is of interest for current large scale laser projects based on optical parametric amplification. He designed and developed highly efficient ultra-broadband Optical Parametric Amplification (OPA) stages in the femtosecond and picosecond regime, as well as the associated temporal diagnostics. The systems were implemented at the Laboratory for Intense Lasers (IST) and at the Vulcan laser system (CLF) in the scope of facility upgrades for laser-plasma interaction and pump-probe experiments.

Additionally, he investigated one of the most promising applications of ultrashort, high-intensity lasers: Target Normal Sheath Acceleration (TNSA), which finds applications such as radiotherapy, isotope production, fusion fast ignition schemes and proton imaging. The experimental research for this topic was conducted in collaboration with the SPARC-LAB group at LNF-INFN (Italy).

After being awarded the top final grade of Approved with Distinction Cum Laude at his PhD defence, Mario returned to Italy, where he is now a researcher at Frascati National Laboratory.

Congratulations Mario!

Farewell to Mario

Tue, 22 Sep 2020 00:00:00 +0000

Mario Galletti has left the team and moved to star an Assistant Professor at the Physics Department of the Università degli Studi di Roma – Tor Vergata, Rome, Italy.

During his stay in our team, Mario was extremely prolific and spread his research activity over several areas, from optical parametric oscillation and amplification, nonlinear optical crystals, optical diagnostics, FROG and GRENOUILLE pulse diagnostics, as well as contributing to experiments on electron acceleration through laser plasma interaction. He published 9 papers in the scope of his PhD thesis, which received national and international awards.

Tanti auguri Mario!

Paper accepted and featured in HPLSE

Mon, 21 Sep 2020 00:00:00 +0000

Mario Galletti’s work on optimising ultra-broadband optical parametric amplification in BiBO and YCOB at L2I has now been accepted for publication in High Power Laser Science and Engineering. Additionally, the work is selected as Editor’s Pick and features on the cover of this issue (image above).

In this work, we evaluate and demonstrate ultra-broadband near-infrared noncollinear optical parametric amplification in two nonlinear crystals, bismuth borate (BiBO) and yttrium calcium oxyborate (YCOB), which are not commonly used for this application. The spectral bandwidth is of the microjoule level; the amplified signal is ≥ 200 nm, capable of supporting sub-10 fs pulses. These results, supported by numerical simulations, show that these crystals have a great potential as nonlinear media in both low-energy, few-cycle systems and high peak power amplifiers for terawatt to petawatt systems based on noncollinear optical parametric chirped pulse amplification (NOPCPA) or a hybrid.

M. Galletti, H. Pires, V. Hariton, J. Alves, P. Oliveira, M. Galimberti and G. Figueira, Ultra-broadband near-infrared NOPAs based on the nonlinear crystals BiBO and YCOB. High Power Laser Sci. and Engin. 8, e29 (2020)

New laser arrives

Sat, 12 Sep 2020 00:00:00 +0000

Our new mid-infrared laser has arrived and has been successfully installed!

The system consists of:

Amphos pump laser: 100 kHz, 100 W, 1 ps, 1 mJ/pulse, 1030 nm
Fastlite OPCPA: 100 kHz, 6 W, 40 fs, 60 µJ/pulse, 3100 nm, with CEP stability (<150 mrad rms)

This system is the main component in the scope of the National Roadmap project at IST. It is complemented by a fast acquisition rack device (Fastlite Big Brozzer), a mid-infrared spectrometer (Fastlite Mozza), and a beam stabilization system for the pump laser (MRC Systems).

The new lasers (1030 nm and 3100 nm) will be used for experiments on nonlinear optics and harmonic generation.