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.
Several members of the Group of Applications Laser and Photonics (ALF – USAL) present the results of their research in the Poster Sessions organized during the XIII National Meeting of Optics (RNO 2021) that is taking place virtually from November 22 to 24 of 2021.
The works presented are included below:
Authors: Alba de las Heras, Alok Kumar Pandey, Julio San Román, Javier Serrano, Elsa Baynard, Guillaume Dovillaire, Moana Pittman, Charles G. Durfee, Luis Plaja, Sophie Kazamias, Olivier Guilbaud, y Carlos Hernández–García
Abstract: Structured light in the short-wavelength regime is emerging as a paramount tool to explore ultrafast spin and electronic dynamics. In this work, we demonstrate experimentally and theoretically the up-conversion of Vector-Vortex Beams (VVB) from the IR to the XUV regime, introducing a unique configuration of XUV coherent radiation spatially structured in its polarization and phase. The build-up of high-order harmonic generation driven by VVB is governed by the conservation of the Pancharatnam topological charge, which considers the intertwined spin and orbital angular momentum properties. The selection rule results in harmonic VVB with a high topological charge and smooth propagation dynamics.
Authors: Victor Segundo-Staels, Enrique Conejero Jarque y Julio San Roman1.
Abstract: The development of short, pulsed lasers has paved the way of new scientific disciplines such as the femtochemistry or the attoscience. There are several well-known schemes to generate extremely short pulses, such as the post-compression techniques. One of the most used post-compression methods consists of the spectral broadening of the pulse via its nonlinear propagation through a hollow-core capillary filled with a gas. The post-compressed pulse obtained, after passing a phase compensation stage, can reach the few- and even single-cycle regime.
We have developed a numerical model to study the nonlinear propagation of a laser pulse in an MPC. It is based on the standard Split-Step Fourier scheme in 4 dimensions, namely 3 cartesian coordinates plus the time dimension, as done by M. Hanna and co-workers7. As usual, the nonlinearities are processed in the space-time domain and linear effects in the frequency domain. Our code is written in MATLAB, employing some recent storage functions that allow us to work with big amounts of data. Normally we use a resolution grid of 128x128x512x𝑍 points, where 𝑍 is the propagation coordinate, which could be adjusted with adaptative steps based on the nonlinearity demands. With this precision we solve the propagation of tens of roundtrips in short amounts of time, which allows us to have bigger accuracy in transversal or temporal coordinates. Currently, we are able to retrieve previous results from the literature of spectral broadening in MPCs. This will allow us to study the behaviour of MPCs in different scenarios and to study the role of other nonlinear terms that could be relevant in some situations.
Authors: Rodrigo Martín, Luis Plaja y Carlos Hernández – García.
Abstract: El auge del estudio de haces de luz estructurados en los últimos años ha permitido demostrar nuevos esquemas en los procesos de interacción láser-materia. Un ejemplo son los haces de luz vectoriales con polarización azimutal, mostrando un campo magnético longitudinal oscilante a frecuencias ópticas. Estos campos magnéticos pueden llegar a ser del orden de giga-Tesla para intensidades máximas del haz vectorial en el rango de 10²¹ W/cm². En este trabajo se ha estudiado cómo estos campos magnéticos pueden afectar al proceso de generación de armónicos de orden elevado. Hemos observado cómo los espectros mejoran de manera notable tanto en eficiencia como en la frecuencia máxima que puede llegar a generarse. Además hemos dado una explicación desde un punto de vista fundamental de la dinámica que sufre el electrón durante su excursión por el continuo bajo el efecto del campo magnético. Por un lado, se produce una reestructuración de los niveles del continuo de manera análoga a un hilo cuántico, debido al confinamiento transversal del campo magnético. Por otro lado, la función de onda del electrón, tras la fotoionización, sufre de una dinámica de revivals o sucesivas focalizaciones que permite entender el aumento de las eficiencias y las frecuencias máximas que pueden obtenerse. Este trabajo presenta un nuevo esquema de la interacción láser-materia con la nueva generación de láseres de petavatio actualmente en construcción.
Authors: Marina Fernández Galan, Julio San Román y Enrique Conejero Jarque.
Abstract: Gas-filled hollow-core fibers (HCFs) have been extensively used for generating intense ultrashort laser pulses, which are now essential tools in disciplines such as ultrafast spectroscopy or attosecond science. In this work, we have studied the generation of few-cycle pulses in HCF compressors with non-uniform pressure along the fiber. Varying the gas pressure, both dispersion and nonlinearity can be easily tuned, yielding output pulses with extremely short durations and a clean temporal profile.
Authors: Miguel López-Ripa, Íñigo Sola y Benjamín Alonso
Abstract: Las técnicas de caracterización espaciotemporal de pulsos ultracortos han ganado gran importancia a lo largo de las últimas décadas. En este trabajo hemos implementado un sistema de caracterización espaciotemporal compacto y ultraestable basado en interferometría por desplazamiento lateral en un montaje monolítico. Además, lo hemos empleado para caracterizar vórtices ópticos ultracortos generados usando láminas nanoestructuradas, demostrando su viabilidad y abriendo la puerta a explorar y optimizar nuevos casos de interés en aplicaciones de óptica ultrarrápida.
More information in:
“Transverse phase matching of high-order harmonic generation in single-layer graphene”, Roberto Boyero-García, Óscar Zurrón-Cifuentes, Luis Plaja, and Carlos Hernández-García, Optics Express 29, 2488-2500 (2021).
References:
[1] “Carrier-envelope-phase insensitivity in high-order harmonic generation driven by few-cycle laser pulses”, C. Hernández-García, W. Holgado, L. Plaja, B. Alonso, F. Silva, M. Miranda, H. Crespo, and I. J. Sola, Optics Express 23, 21497 (2015)
Download in Gredos@Universidad de Salamanca: http://hdl.handle.net/10366/146004
The National Meeting of Optics of the year 2021 (RNO2021) will take place next week from November 22 to 24. In this online event that has more than 240 registered people and 19 sponsors, more than 200 scientific contributions will be presented.
The National Meeting of Optics (RNO) is a triennial congress organized by the Spanish Society of Optics (SEDOPTICA), which has a long history of more than 30 years. An average of 200 professionals from different specialties of Optics and Photonics in Spain converge in each RNO and it is where the latest scientific and technological advances in this field are presented.
The XIII RNO 2021, organized this year by the SEDOPTICA Women, Optics and Photonics Area, aims to maintain the high quality standards of this conference, placing special emphasis on creating a parity and attractive congress for younger researchers.
Being one of the main events related to research in the field of optics and photonics, it is an essential appointment in the calendar of the members of the Laser and Photonics Applications Group.
This year, the Laser and Photonics Applications Group present the following contributions:
In addition, several members of the GIR Laser and Photonics Applications participate in the following spaces within RNO2021:
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!
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.
Bridging the Gap Between Fundamental Ultrafast EUV Science and Practical Metrologies for the Semiconductor Industry
High-harmonic generation (HHG) is nature’s most extreme nonlinear process known to date and, for just over 30 years, it has enabled the realization of table-top, short-pulsed extreme ultraviolet (EUV) and soft X-ray sources that are currently defining new paradigms in functional, nanoscale spectroscopy and imaging.
After decades of combined theoretical and experimental efforts, the underlying mechanism of gas-phase HHG is well understood and it is now known that the quantum physics behind the HHG process can be exploited to tailor the spectral, temporal, spatial, and angular momentum properties of the emitted short-wavelength light. In parallel, advancements in HHG system design have now resulted in robust, bright, and near turn-key systems for producing tunable, coherent EUV light for advanced metrology applications. In this light, imec has recently installed and commissioned the imec AttoLab, a first-of-its-kind, ultrafast, HHG-based EUV metrology and lithography lab with primary aims of performing high-NA EUV lithography and ultrafast materials characterization.
In this talk, Dr. Kevin Dorney will give an overview of imec’s AttoLab, its infrastructure, and the current and foreseen ultrafast spectromicroscopies that will be deployed for characterization of novel semiconductor materials. In addition to spectroscopy and imaging capabilities, the lithographic capabilities of AttoLab will be presented, as well as the first interference lithography results obtained with a 13.5 nm, HHG-based EUV system. Finally, Dr. Kevin Dorney will give some perspectives and outlook on how HHG-based light sources can further benefit semiconductor metrology and lithography, in particular to the use of structured EUV light for advanced inspection and metrology of devices and materials.
Seminar’s poster can be downloaded here.
The video of the seminar will be available on the Youtube account of the Laser and Fotonica Applications group once seminar ends.
Presenter bio
Kevin Dorney is a postdoctoral researcher and MSCA fellow in AttoLab at imec in Leuven, Belgium. He received B.S. degrees in Biology and Chemistry (2012) as well as an M.S. in Chemistry (2014) from Wright State University (Ohio, USA). In 2019, he earned a Ph.D. in Chemical Physics under the supervision of Profs. Margaret Murnane and Henry Kapteyn in JILA at the University of Colorado Boulder, specializing in the HHG-based generation of structured EUV beams with tailored spin and orbital angular momentum. His current research interests involve the deployment of bright, coherent 13.5 nm EUV light from HHG systems to investigate the ultrafast radiochemistry of the EUV exposure mechanism in photoresists, as well as their use in lithographic processes for resist screening and advanced metrologies to facilitate learning cycles as the semiconductor industry transitions to high-NA EUV lithography.
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.
The European Union Competition for Young Scientists, better known as “EUCYS”, awards and celebrates the best young scientific talent in Europe. Every year, the contest brings together promising young scientists from across Europe and beyond to present their projects to an international jury.
Although the 32nd edition should have been held in Salamanca in 2020, the global COVID 19 pandemic forced the European Commission to make the decision to postpone it. From September 16 to 19, the University of Salamanca will host the 32nd edition that combines the 2020 and 2021 competitions, which takes place semi-face-to-face.
All the works that are presented in the competition are available on the event’s website.
Carlos Hernández-García, member of the ALF-USAL group, belongs to the organizing committee of the event.
The University of Salamanca (Spain) invites applications for a 3-years postdoc position starting in October/November 2021. The position is part of the project ATTOSTRUCTURA, “Structured attosecond pulses for ultrafast nanoscience”, funded by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 851201), supervised by Dr. Carlos Hernández-García, and with a duration of 5 years.
Application deadline: August 30th 2021
The postdoctoral researcher will enrol the project “Structured attosecond pulses for ultrafast nanoscience” at the Laser Applications and Photonics Research group (ALF-USAL) at University of Salamanca. ALF-USAL is an interdisciplinary Optics research group with expertise in both theory (strong-field physics, nonlinear optics, ultrafast phenomena, attosecond science) and experiments (ultrashort pulse characterization, pulse shaping, photonic crystals, ultrashort micro-machining). Some of the recent results have been published in high impact factor scientific journals:
– “Generation of extreme-ultraviolet beams with time-varying orbital angular momentum”, L. Rego, K. M. Dorney, N. J. Brooks, Q. Nguyen, C-T. Liao, J. San Román, D. E. Couch, Allison Liu, E. Pisanty, M. Lewenstein, L. Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, Science 364, eaaw9486 (2019). Highlighted in the media:
– “Controlling the polarization and vortex charge of attosecond high-harmonic beams via simultaneous spin-orbit momentum conservation”, K. M. Dorney, L. Rego, N. Brooks, J. San Román, C-T. Liao, J. L. Ellis, D. Zusin, C. Gentry, Q. Nguyen, J. M. Shaw, A. Picón, L. Plaja, H. C. Kapteyn, M. M. Murnane, C. Hernández-García, Nature Photonics 13, 123–130 (2019).
– “Ultraintense femtosecond magnetic nanoprobes induced by azimuthally polarized laser beams”, M. Blanco, F. Cambronero, M. T. Flores-Arias, E. Conejero Jarque, L. Plaja, C. Hernández-García, ACS Photonics 6, 38–42 (2019)
The candidate will explore the application of ultrashort structured pulses in ultrafast magnetism, an emerging field that is opening exciting scenarios in laser-matter interaction at the most fundamental level, merging the fields of Optics and Magnetism. The candidate will count not only with the collaboration of the research team at ALF-USAL, but also with the collaboration of the research group on simulation of magnetic nanostructures SINAMAG at USAL, in particular with Prof. Luis López-Díaz and Dr. Rocío Yanes.
Successful candidates will have the possibility to consolidate their own independent research lines and to promote collaborative research among the following research lines:
Interested candidates should send a CV (maximum 5 pages), a personal statement with scientific interests and reasons for applying, two contacts for recommendation letters to Dr. Carlos Hernández-García (carloshergar@usal.es)
For further information and inquiries please contact Dr. Carlos Hernández-García (carloshergar@usal.es)
More information about the project, the position and the application process can be found Euraxess web page.
