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XL Semanal highlights the career of Carlos Hernández García

XL Semanal highlights the career of Carlos Hernández García
The magazine XL Semanal highlights the work and outstanding research career of Carlos Hernández García, a member of our research group at the University of Salamanca. In a recent article, the impact of his research in the field of attophysics—a discipline that allows the study of the smallest and fastest phenomena in the subatomic universe—is emphasized.
 

Hernández García, who has been awarded by the BBVA Foundation and the Spanish Royal Society of Physics, leads research that has enabled the generation of ultrafast laser pulses capable of freezing the movement of subatomic particles, such as electrons. This revolutionary technology opens new avenues for studying and controlling matter at the quantum level.

The article highlights not only his ability to unravel the mysteries of quantum physics but also the enormous potential his work holds for future applications in fields as diverse as electronics, energy, and medicine.

You can read the full article on the XL Semanal website and download it from this link.

From our research group, we celebrate the national recognition of these achievements and congratulate Carlos Hernández García for the acknowledgment of his dedication and efforts.

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23 September, 2024 admin , , , No comments
adminXL Semanal highlights the career of Carlos Hernández García

Visit of Researcher ZhenSheng Tao to the Laser Applications and Photonics Group

Visit of Researcher ZhenSheng Tao to the Laser Applications and Photonics Group

From July 19 to 24, the Laser Applications and Photonics Group hosted the visit of Dr. ZhenSheng Tao, a researcher from the State Key Laboratory of Surface Physics and the Key Laboratory of Micro and Nano Photonic Structures (MOE) at Fudan University in Shanghai (P.R. China). The visit provided an excellent opportunity for academic exchange and strengthening collaborations in the field of advanced photonics.

During the visit, Dr. Tao delivered a lecture titled “Solid-state High-order Sideband Spectroscopy and Microscopy”, where he presented his latest research on the ultrafast manipulation of electronic states in quantum materials. This field is crucial for quantum state engineering and ultrafast optical modulation. In his talk, he highlighted how strong-field driven materials can exhibit fascinating properties, such as the modification of topological states, modulation of optical properties, and band structure engineering.

Despite the potential of these properties, experimental techniques to study strong-field dressed quantum states are limited. In response to this challenge, Dr. Tao introduced high-order sideband spectroscopy and microscopy techniques, developed by his team, which enable energy-, time-, and space-resolved measurements of these quantum states. Among the key achievements, he presented the first measurement of the dephasing rates of strong-field dressed exciton states, identifying exciton dissociation as the primary dephasing mechanism. Furthermore, his team achieved the first 3D tomographic imaging of a mid-infrared anapole resonant field in a micrometer-thick silicon resonator.

These advancements highlight the potential of high-order sideband spectroscopy and microscopy as powerful tools for studying the ultrafast manipulation of quantum materials.

The lecture sparked a fruitful exchange of ideas with members of the group, who discussed potential applications and future collaborations in related areas, such as the characterization of materials at the nanoscale using advanced laser techniques. The visit also included a tour of the experimental facilities of the Laser Applications and Photonics Group, where Dr. Tao was able to observe the techniques developed by the local team. This allowed for a valuable technical exchange that laid the foundation for potential collaborative projects in the future.

In summary, Dr. ZhenSheng Tao’s visit was highly enriching, providing new perspectives on solid-state spectroscopy and laying the groundwork for future collaborations. Dr. Tao’s expertise and innovative approach were a great source of inspiration for the group, opening new horizons in the study of photonics and quantum science.

25 July, 2024 admin , No comments
adminVisit of Researcher ZhenSheng Tao to the Laser Applications and Photonics Group

DOCTORAL THESIS DEFENSE ANNOUNCEMENT – Ana García Cabrera

DOCTORAL THESIS DEFENSE ANNOUNCEMENT – Ana García Cabrera

We are pleased to announce the defense of the doctoral thesis of Ana García Cabrera, titled “Efectos de las simetrías del cristal en la generación de armónicos altos en grafeno.” The defense will take place on Monday, July 29th, at 11:00 in Aula III of the Edificio Trilingüe. The thesis directors are Dr. Luis Plaja Rustein and Dr. Carlos Hernández García.

We cordially invite you to attend this important presentation, as your presence and support will be greatly appreciated.

22 July, 2024 admin , No comments
adminDOCTORAL THESIS DEFENSE ANNOUNCEMENT – Ana García Cabrera

OP SESSION – SOLID-STATE HIGH-ORDER SIDEBAND SPECTROSCOPY AND MICROSCOPY

OP SESSION – SOLID-STATE HIGH-ORDER SIDEBAND SPECTROSCOPY AND MICROSCOPY

Zhensheng Tao from the State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (MOE) at Fudan University in Shanghai (P.R. China), will deliver a seminar titled “Solid-state High-order Sideband Spectroscopy and Microscopy” on July 23rd at 12:00 PM.

The seminar will take place in Classroom VII of the Trilingual Building at the University of Salamanca.

Abstract

Ultrafast manipulation of electronic states in quantum materials is essential for quantum-state engineering and ultrafast optical modulation. Recently, strong-field driven materials have exhibited fascinating tailored properties, including modification of topological states, modulation of optical properties and band-structure engineering. However, experimental methods for accessing the properties of strong-field dressed quantum states are lacking. In this talk, I will present our recently developed high-order sideband spectroscopy and microscopy techniques, which enables energy-, time- and space-resolved measurements on strong-field dressed quantum states or near-field wave phenomena. We present the first measurement on the dephasing rates of strong-field dressed exciton states, and resolve the strong-field exciton dissociation as the major dephasing mechanism. Furthermore, we realize the first 3D tomographic near-field tomographic imaging of a mid-infrared anapole resonant field in a micrometer-thick silicon resonator. These results highlight the high-order sideband spectroscopy and microscopy as a powerful tool for studying ultrafast manipulation of quantum materials.

Figure (a) Illustration of measuring the exciton dephasing rates using high-order sideband spectroscopy. (b) Illustration of imaging near-field distribution in dielectric optical resonators.

16 July, 2024 admin No comments
adminOP SESSION – SOLID-STATE HIGH-ORDER SIDEBAND SPECTROSCOPY AND MICROSCOPY

Visit and Collaboration of Ming-Chang Chen with the ALF Group at the University of Salamanca

Visit and Collaboration of Ming-Chang Chen with the ALF Group at the University of Salamanca
We are delighted to announce that Ming-Chang Chen from the National Tsing Hua University in Hsinchu, Taiwan, visited the Laser Applications Group at the University of Salamanca (USAL) from July 8th to July 10th, 2024. During his visit, in addition to holding meetings with the group’s researchers and touring the laboratory, he delivered a lecture on July 10th titled “Advancements in Turn-Key Attosecond Light Sources and Their Application in Probing Spin Dynamics.”
 

The collaboration between Ming-Chang Chen and the ALF group has a long history, dating back to 2016. As a result of this collaboration, several research articles have been published, thereby strengthening the bond between both institutions and significantly advancing the field of laser technology.

  1. Chang, K.-Y., Huang, L.-C., Asaga, K., Tsai, M.-S., Rego, L., Huang, P.-C., Mashiko, H., Oguri, K., Hernández-García, C., & Chen, M.-C. (2021). High-order Nonlinear Dipole Response Characterized by Extreme-Ultraviolet Ellipsometry. Optica, 8, 484-492. https://doi.org/10.1364/OPTICA.413531
  2. Chang, K.-Y., Huang, L.-C., Asaga, K., Tsai, M.-S., Rego, L., Huang, P.-C., Mashiko, H., Oguri, K., Hernández-García, C., & Chen, M.-C. (2021). High-order Nonlinear Dipole Response Characterized by Extreme-Ultraviolet Ellipsometry. Optica, 8, 484-492. https://doi.org/10.1364/OPTICA.413531
  3. P. -C. Huang, C. Hernández-García, J. -T. Huang, P. -Y. Huang, L. Rego, C. -H. Lu, S. -D. Yang, L. Plaja, A. H. Kung, & M. -C. Chen. (2019). Realization of Polarization Control in High-Order Harmonic Generation. IEEE Journal of Selected Topics in Quantum Electronics, 25(4), 1-12. https://doi.org/10.1109/JSTQE.2019.2919777

Prof. Chen established the ATTO-EUV lab in 2013 with the goal of generating bright and coherent EUV lasers on a tabletop. His recent research is dedicated to advancing laser technology and producing the shortest and brightest high-order harmonic EUV source. Notably, he pioneered and demonstrated the complete solution for controlling the polarization of isolated attosecond pulses and invented the broadband EUV polarimeter. By introducing the highly efficient post-compression technique, CASCADE, he enabled the production of single-cycle IR pulses and isolated attosecond EUV pulses. This accessible and reliable tabletop EUV light source has opened up numerous possibilities, including pioneering EUV spectroscopic ellipsometry and achieving the brightest EUV light source for nano-imaging.
11 July, 2024 admin , No comments
adminVisit and Collaboration of Ming-Chang Chen with the ALF Group at the University of Salamanca

OP SESSION – Laser harmonic generation: a beat wave on steroids

OP SESSION – Laser harmonic generation: a beat wave on steroids

Raoul Trines from STFC Rutherford Appleton Laboratory in Didcot (United Kingdom) will deliver the seminar titled “Laser Harmonic Generation: A Beat Wave on Steroids” on July 11th at 12:00 PM.

The seminar will take place in room VII of the Trilingual Building at the University of Salamanca.

Summary:
 

The laser beat-wave concept was developed in the 1980s to generate waves in low-density plasma using dual-frequency lasers. In this process, sidebands are generated in the electromagnetic wave spectrum. In this talk, we show that the beat-wave concept can also be used to study laser harmonic generation for both Gaussian beams and higher-order laser modes (e.g., Laguerre-Gaussian).

We present a novel framework to study laser harmonic generation, considering it as a multi-dimensional beat-wave process [1]. This framework allows us to calculate and visualize harmonic progressions more easily. It also includes a specific way to simultaneously analyze the frequency, spin, and orbital angular momentum (OAM) content of the harmonic radiation, providing deeper insight into this process.

We will apply our framework to the interaction of laser pulses with structured targets and show that we can achieve tunable OAM spectra and frequency combs in this configuration. We will also use our methods to analyze harmonic generation in nonlinear optics involving higher-order phase and polarization topologies, thus demonstrating that our results have many applications beyond laser-solid interactions.

[1] R. Trines et al., “Laser harmonic generation with independent control of frequency and orbital angular momentum”, Nature Communications, in press (2024), https://doi.org/10.21203/rs.3.rs-3458883/v1

Top: Schematic illustrating the generation of higher order harmonics (blue: σ= 1; green: σ=−1) of an incoming CP pump pulse (red) in (a) reflection and (b) transmissive configurations, from a threefold structured target. Bottom: Expected 2D harmonic spectrum from: (c), a flat target driven by a LP pump pulse with ℓ= 1; (d) a target with a circular structure hit by a CP pump pulse of ℓ= 0; and (e), a target with a threefold structure hit by a CP pump pulse of ℓ= 0). The blue shaded area indicates the potential for a frequency comb at ℓ= 0

11 July, 2024 admin No comments
adminOP SESSION – Laser harmonic generation: a beat wave on steroids

Participation of the ALF USAL Group in RNO2024

Participation of the ALF USAL Group in RNO2024

The ALF USAL group had a prominent participation in the XIV National Optics Meeting and the V National Young Optics Meeting (RNO2024) held from July 2 to 5 in Murcia, Spain.

This event, which brings together leading experts and young talents in the field of optics, has been an exceptional platform to present the latest advances in research and development in this field.

The group contributed with a series of works that address various areas of modern optics, standing out for their innovation and scientific rigor. The presented works are summarized below:

  1. Attosecond Structured Light (Invited)
    Autor: Hernández García, C.
  2. Diseño de guías de ondas superficiales optimizadas para sensado y extracción de luz en materiales cristalinos fabricadas mediante escritura directa con láser de femtosegundo (Oral)
    Autores: Arroyo Heras, V., López Quintas, I., Vázquez De Aldana, J. R., Bonduelle, M., Martín, G., & Romero Vázquez, C.
  3. Medida de pulsos ultracortos vectoriales con amplitude swing (Oral)
    Autores: Barbero, C., Alonso, B., & Sola Larrañaga, I. J.
  4. Towards an all-fiber source of isolated attosecond pulses driven by high-energy sub-cycle waveforms from soliton dynamics (Oral)
    Autores: Fernández Galán, M., Serrano, J., Conejero Jarque, E., Borrego-Varillas, R., Lucchini, M., Reduzzi, M., Nisoli, M., Brahms, C., Travers, J. C., Hernańdez-García, C., & San Román, J.
  5. Sistema óptico aplicado a la espectroscopía resuelta en tiempo en el rango de femtosegundo y picosegundo (Oral)
    Autores: Guerras, M., Lópe Quintás, I., & Sola Larrañaga, I. J.
  6. Intense and isolated polarization-controlled magnetic fields from structured laser beams to drive nonlinear magnetization dynamics (Oral)
    Autores: Martín Domene, S., Sánchez-Tejerina, L., Martín-Hernández, R., & Hernández García, C.
  7. Generation of extreme-ultraviolet high-topological charge spatiotemporal optical vortices (Oral)
    Autores: Martín-Hernández, R., Gui, G., Plaja, L., Kapteyn, H. C., Murnane, M. M., Liao, C.-T., Porras, M. Á., & Hernandez-Garcia, C.
  8. Self-interference of Hermite-Gaussian high-order harmonics simulated through machine learning (Oral)
    Autores: Pablos-Marín, J. M., Schmidt, D., De Las Heras, A., Westlake, N., Serrano, J., Lei, Y., Kazansky, P., Adams, D., Durfee, C., & Hernández García, C.
  9. Topological spectroscopy: High Harmonic Generation from Graphene irradiated by structured fields (Oral)
    Autores: Plaja, L., García Cabrera, A., Boyero-García, R., Zurrón-Cifuentes, O., Serrano, J., San Román, J., & Hernández-García, C.
  10. Improving pulse self-compression in photonic crystal fibers using particle swarm optimization algorithm. (Oral)
    Autores: Vaquero, A., Galán, M. F., Rodríguez Frías, M. D., Conejero Jarque, E., & Méndez, C.
  11. Macroscopic simulations of high-order harmonic generation assisted by artificial intelligence. (Oral)
    Autores: Serrano, J., Pablos-Marín, J. M., & Hernández García, C.
  12. Clean Temporal Pulses from All-Bulk Multipass Cells. (Oral)
    Autores: Segundo-Staels, V., Conejero Jarque, E., & San Roman, J. 
  13. Microscopía de generación de segundo armónico en cristales microestructurados con pulsos de femtosegundo: BBO y Nd:YAG. (Oral)
    Autores: Sevilla-Sierra, N., Rodríguez Vázquez de Aldana, J., Romero Vázquez, C., Mateos, X., & López Quintas, I.
  14. PW-class laser spatio-temporal characterization (Póster)
    Autores: Barbero, C., García-García, E., Mendez, C., Rodríguez Frias, M. D., López-Ripa, M., Sola Larrañaga, I. J., & Alonso Fernández, B.
  15. Fabricación de dispositivos fotónicos funcionales mediante escritura directa con láseres de femtosegundo. (Póster)
    Autores: Romero Vázquez, C., Arroyo Heras, V., Sevilla Sierra, N., López Quintás, I., & Vázquez De Aldana, J. R. 

In addition to presenting their work, the researchers from the ALF USAL group also contributed to the conference by moderating several oral communication sessions:

  • Luis Plaja, moderator of the Quantum and Nonlinear Optics session on Wednesday, July 3
  • Carlos Hernández García, moderator of the Quantum and Nonlinear Optics session on Thursday, July 4

These works reflect the ALF USAL group’s commitment to scientific excellence and their ability to lead in the field of optical research. The diversity and depth of their studies presented at RNO2024 underscore their crucial role in advancing modern optics.

8 July, 2024 admin , No comments
adminParticipation of the ALF USAL Group in RNO2024

OP Session – Advancements in Turn-Key Attosecond Light Sources and Their Application in Probing Spin Dynamics

OP Session – Advancements in Turn-Key Attosecond Light Sources and Their Application in Probing Spin Dynamics

Ming-Chang Chen from National Tsing Hua University in Hsinchu, Taiwan, will deliver the seminar titled “Advancements in Turn-Key Attosecond Light Sources and Their Application in Probing Spin Dynamics” next Wednesday, July 10th at 1:00 PM.

The seminar will take place in the basement classroom of the Trilingual Building at the University of Salamanca.

Abstract: 
 

Prof. Chen established the ATTO-EUV lab in 2013 with the goal of generating bright, coherent tabletop EUV lasers. His recent research is dedicated to advancing laser technology and generating the shortest and brightest high-order harmonic EUV source. Notably, he pioneered and demonstrated the complete solution for the polarization control of isolated attosecond pulses and invented the broadband EUV polarimeter. Introducing the highly efficient post-compression technique, CASCADE, he enabled the production of one-cycle IR pulses and isolated attosecond EUV pulses. This accessible and reliable tabletop EUV light source has opened up numerous possibilities, including the first EUV spectroscopic ellipsometry and the brightest EUV light source for nano-imaging.

 
2 July, 2024 admin No comments
adminOP Session – Advancements in Turn-Key Attosecond Light Sources and Their Application in Probing Spin Dynamics

Participation in the XVII National Congress on Materials CNMAT24

Participation in the XVII National Congress on Materials CNMAT24

We are pleased to announce that three researchers from the Laser Applications and Photonics Group at the University of Salamanca have participated in the XVII Edition of the National Congress on Materials (CNMAT24). The congress took place from June 25 to 28, 2024, in the city of Málaga and brought together national and international experts in the field of materials.

Researchers Pablo Moreno Pedraz, Javier Rodríguez Vázquez de Aldana, and Ignacio López Quintás presented their latest work at this prestigious event, highlighting advancements and innovative applications in the field of photonics and laser technology.

  • Javier Rodríguez Vázquez de Aldana participated as the moderator of the Laser Material Processing symposium and also presented the poster titled “Microstructuring of transparent crystalline materials with ultrashort pulse lasers: new developments and applications.”
  • Pablo Moreno Pedraz presented the work titled “Influence of the substrate and thickness on the formation of LIPSS in thin polymer films.”
  • Ignacio López Quintás presented the work titled “Second harmonic generation in Nd crystals microstructured by laser.”

The participation of our researchers in CNMAT24 not only reinforces our group’s position at the forefront of scientific research but also demonstrates our continuous commitment to excellence and innovation in the field of photonics and laser technology.

Congratulations to Pablo, Javier, and Ignacio for their outstanding contribution and for representing our group and the University of Salamanca so well at this important event!
28 June, 2024 admin , No comments
adminParticipation in the XVII National Congress on Materials CNMAT24

PARTICIPATION OF RESEARCHERS FROM THE LASER AND PHOTONICS APPLICATIONS GROUP IN ICOAM2024

PARTICIPATION OF RESEARCHERS FROM THE LASER AND PHOTONICS APPLICATIONS GROUP IN ICOAM2024
Researchers Carlos Hernández García and Rodrigo Martín-Hernández, members of the Laser and Photonics Applications Group and the ERC Attostructura project (851201), actively participated in the Seventh International Conference on Optical Angular Momentum. This prestigious conference took place from June 10 to 13, 2024, at Kruger National Park, South Africa.
 

The Seventh International Conference on Optical Angular Momentum (ICOAM 2024) is a prominent event in the field of optics and photonics, focusing on the study and applications of light’s angular momentum. This event gathers scientists and experts from around the world to discuss the latest advancements and share innovative research in areas such as particle manipulation, quantum optics, generation of angular momentum beams, and biomedical and communication applications.

  • Carlos Hernández García participated as an invited speaker with his work titled “Attosecond vortex pulse trains”.

The landscape of ultrafast structured light pulses has recently evolved thanks to the capability of high-order harmonic generation (HHG) to nonlinearly convert orbital angular momentum (OAM) from infrared to extreme-ultraviolet/soft X-rays. Up to now, HHG has been demonstrated to produce harmonic vortex pulses on the femtosecond scale through various studies, where higher-order harmonics exhibit distinct OAM content. This characteristic, a result of OAM conservation rules, has hindered the emission of vortex beams with attosecond pulse durations.

In this work, we demonstrate, both theoretically and experimentally, the generation of attosecond vortex pulse trains – a succession of light pulses each with a temporal duration of hundreds of attoseconds, and a similar helical wavefront. This achievement is realized by synthesizing a comb of high-order harmonics with identical OAM. To our knowledge, these are the first vortex pulses produced on the attosecond scale.

To achieve this, we drove HHG with an infrared bifurcated polarization tilt-angle grating, resulting from the non-collinear superposition of two counter-rotating circularly polarized beams with opposite OAM. The simultaneous conservation of linear momentum, spin angular momentum, and orbital angular momentum in the HHG process leads to two spatially-separated circularly polarized high-order harmonic beams with OAM independent of the order. Our work paves the way towards attosecond-resolved light-matter interactions at the natural timescale of electronic dynamics in atoms, molecules, or solids.

  • Rodrigo Martín-Hernández participated in the poster session with the work titled “How to generate spatiotemporal optical vortices in the extreme-ultraviolet/x-ray regime.”

The generation of spatiotemporal optical vortices (STOVs) in the near-infrared regime has been successfully studied in recent years, both theoretically and experimentally. However, their extension to higher-frequency regimes has not yet been demonstrated. Over the last decade, it has been shown that high-order harmonic generation (HHG) can successfully transfer longitudinal optical vortices from the near-infrared to the extreme-ultraviolet (EUV) and X-ray regimes. Following an immediate analogy, one might think that HHG driven by STOVs would result in high-frequency STOVs with high topological charge. However, this scenario offers much richer possibilities.

In this work, we explore the nonlinear conversion of STOVs from the near-infrared to EUV/X-rays using HHG. Depending on the driving beam configuration, we identify two scenarios that lead to strongly differentiated phenomena.

Firstly, if HHG is driven by a canonical, elliptical, single-charged STOV focused on a gas target, high-frequency harmonic STOVs with the same topological charge as the driving field are generated. Our theoretical calculations unequivocally demonstrate that this result depends heavily on the non-perturbative nature of the HHG process. Thus, these results not only provide harmonic combs of low-topological charge STOVs in the EUV/X-ray range but also open the door to investigating some of the most fundamental questions about the intrinsic non-perturbative nature of the HHG process.

Secondly, if the driving beam is designed to deliver a canonical (elliptical), single-charged STOV at the gas target, high-order harmonic STOVs with high topological charge are generated. We demonstrate that in this scenario, the resulting topological charge of the harmonic STOVs increases according to the harmonic order multiplied by the fundamental topological charge, following the same well-known conversion rule as in longitudinal optical vortices.

Carlos Hernández García and Rodrigo Martín-Hernández’s participation in ICOAM 2024 underscores the Laser and Photonics Applications Group’s commitment to cutting-edge research and international collaboration in the field of optics and photonics. Their work not only contributes to the advancement of scientific knowledge but also opens new opportunities for innovative technological applications.

28 June, 2024 admin , , No comments
adminPARTICIPATION OF RESEARCHERS FROM THE LASER AND PHOTONICS APPLICATIONS GROUP IN ICOAM2024