Scientific outreach

Jila Press Release – A Necklace Made of Doughnuts

Our friends and frequent collaborators from JILA (University of Colorado) echo the paper “Necklace-structured high-harmonic generation for low-divergence, soft x-ray harmonic combs with tunable line spacing” recently published in ScienceAdvances.

You can read his review at the following link: https://jila.colorado.edu/news-events/articles/necklace-made-doughnuts

More information at:

Rego, L., Brooks, N. J., Nguyen, Q. L. D., San Roman, J., Binnie, I., Plaja, I., Kapteyn, H. C., Murnane, M. M., & Hernández-García, C. (2022). Necklace-structured high-harmonic generation for low-divergence, soft x-ray harmonic combs with tunable line spacing. Science Advances, 8(5), eabj7380. https://doi.org/10.1126/sciadv.abj7380
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Compressing light pulses in pressure gradients

In spite of having an extremely short life, of just a few quadrillionths of a second, ultrashort femtosecond laser pulses have become an indispensable tool in many areas of science and technology, as they allow to probe the most fundamental properties of matter on ultrafast time scales.

Generating these such short pulses of light in a controlled manner and with a good quality is not an easy task, and in the last years various strategies have been proposed. The main idea is to generate a very wide light spectrum, made up of many frequencies, by means of nonlinear processes starting from a narrower one, and then correcting its phase to synchronize all the frequencies, giving rise to an ultrashort pulse. A widely used method to achieve this large spectral broadening is to propagate an initial light pulse through a hollow cylindrical fiber filled with a gas. In this case, one of the parameters that most influences the propagation is the pressure of the filling gas, which allows for a continuous tuning of the dispersion and the intensity of the nonlinear effects experienced by the pulse. In particular, if the fiber and gas parameters are carefully chosen, the incident pulse can broaden its spectrum while correcting its phase due to the interaction between the linear and nonlinear processes. In this way, the pulse reduces its duration on its own, in a process known as soliton self-compression.

Usually, these experiments are carried out keeping the gas at constant pressure, homogeneously filling the fiber. However, in one of our latest studies we have shown that applying a decreasing pressure gradient, causing the gas concentration to gradually decrease during propagation, can improve the quality of the self-compressed pulses and reduce their duration even more than constant pressure.

You can look up for all the details of this work at:

F. Galán, E. C. Jarque, and J. San Roman, Optimization of pulse self-compression in hollow capillary fibers using decreasing pressure gradients, Optics Express 30(5), 6755–6767 (2022). https://doi.org/10.1364/OE.451264

Download the full paper at Gredos @Universidad de Salamanca: http://hdl.handle.net/10366/148576
 
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Attostructura Seminar – Structuring ultrafast laser light through highly nonlinear physics

On February 2nd, Carlos Hernández García, Ramón y Cajal researcher, member of the Laser and Photonic Applications research group and principal investigator of the Attostructura project (ERC 851201) gave the seminar “Structuring ultrafast laser light through highly nonlinear physics” within the cycle of seminars of the Rocasolano Institute of the CSIC.

The degree of control we have achieved over the manipulation of light is truly amazing. Initiated by our Greek ancestors using mirrors to guide light, we live in a world where the most advanced laser technology allows us to create and sculpt light beams with great precision. In particular, nowadays we can create ultrashort attosecond pulses (with durations of trillionths of a second), of very high frequencies (up to the soft X-rays), and with increasingly complex spatial structures thanks to our ability to harness their angular momentum. In this talk we will review our recent work in the generation of structured ultrashort laser pulses. Thanks to the highly nonlinear process of high harmonic generation, we can tailor the spin and orbital angular momentum properties of extreme ultraviolet/soft x-ray laser pulses directly at their generation. By properly controlling the process of high harmonic generation, from the driving laser beam to the target (gas or solid), different families of structured ultrashort laser beams can be created: self-torqued beams, vector-vortex beams, tunable high-frequency combs, or hexagonal harmonic beams. These new optical tools allow us to fantasize of new laser-matter interaction processes at the nanoscale, whose physical laws are yet to be discovered. For example, structured laser pulses offer an appealing alternative to study sub-femtosecond magnetization dynamics, where a complete understanding of the electronic and spin interactions remains unexplored

You can see the full video of the seminar on this page or on Youtube channel of the Rocasolano Institute.

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OP Session – Laser diode degradation: Physical models and resolution by Finite Element Methods (FEM)

Jorge Souto, from the University of Valladolid, will give the seminar entitled “Degradation of laser diodes: physical models and resolution by finite element methods (FEM)” on December 14 at 11:30.

The seminar is open to all who want to attend, it will take place in the Aula Sancho Guimerá (Exactas) of the Faculty of Sciences of the University of Salamanca.

The entire seminar will be uploaded to this website and to the YouTube channel of the ALF-USAL group.

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OP Session – Deep Learning and harmonic generation

Javier Serrano, member of the Laser and Photonics Applications group and researcher in the ATTOSTRUCTURA project (ERC 851201), will give the seminar entitled “Deep Learning and harmonic generation” on December 17 at 10:00.

The seminar will take place in Room III of the Faculty of Sciences of the University of Salamanca.

For those who cannot attend, the entire seminar will be uploaded to this website and to the YouTube channel of the ALF-USAL group.

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Carlos Hernández, Young Scientist Prize In Atomic, Molecular and Optical Physics 2021

On June 8, the researcher Carlos Hernández García received the Young Scientist Prize In Atomic, Molecular and Optical Physics 2021 awarded by the International Union of Pure and Applied Physics (IUPAP) for his:

“…outstanding contributions to the theory and modeling of laser-driven high harmonic generation (HHG), both in high photon energy regimes, and in understanding how to manipulate the HHG waveforms to impart orbital and spin photon angular momentum, combining quantum simulations with laser Physics.”

You can read the press release published by iUPAP in this link and see the video that Carlos Hernández has recorded for the University of Salamanca where he talks about the main lines of research and activities of the Laser and Photonics Applications group, about the Attostructura project (ERC 851201) and the recent discoveries that have earned it this recognition.

Congratulations Carlos!

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Attostructura Seminar: imec’s AttoLab (Kevin Dorney) – Video

On November 12, Kevin Dorney, postdoctoral researcher and MSCA member of the AttoLab laboratory of imec (Interuniversity Microelectronics Center) in Leuven (Belgium) visited the Laser and Photonics Applications group as part of the activities planned in the ERC Attostructura project.

Kevin Dorney offered us the seminar entitled “Imec’s AttoLab: Bridging the Gap Between Fundamental Ultrafast EUV Science and Practical Metrologies for the Semiconductor Industry” in which he spoke of the laboratory that they have built in the imec facilities, the infrastructure that forms it and the techniques and capabilities they have.

You can see the video of the entire seminar on this page or on our YouTube channel.

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EUCYS 2021 – Winners and videos of the event

The 32nd edition of the European Competition for Young Researchers (EUCYS 2020 – 2021) has ended up being a great success. Congratulations to all the winners!

You can check the complete list of winners at this link.

For all those who could not follow the different events and ceremonies live, or want to see it again, we include below the video of each event. In addition, the program of activities and the videos and posters of all the works that participated in the contest will continue to be available on the contest website.
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EUCYS 2021 – ALF-USAL PRESENTATION VIDEO

From September 16 to 19, 2021, the University of Salamanca will host the 32nd edition of the European Competition for Young Researchers (EUCYS 2020 – 2021).

For this reason, several of the recognized research groups of the University of Salamanca have prepared a video in which they present the group and its main lines of research. Below you can see the video recorded by the GIR of Laser and Photonics Applications (ALF – USAL).

On the website of the contest you can consult the program of activities and see all the events and conferences that are going to be held and the presentation videos of other recognized research groups of the University of Salamanca.
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