Submitted a proposal to the Grant Agency of Czech Republic (GACR)

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A period of proposal drafting has started in the department, and the group of Ultrafast Photonics counts on applying to several funding sources this year to secure financial independence for next years.

On April 1st, a proposal to study the transient excitation of electrons in particular kinds of solids was submitted to the national grant agency. The results are usually known in December of the year of submission. Only 2.5 positions would be potentially funded by this proposal, for people who have already been selected. To secure our positions on a longer time, I am presently participating in drafting of other proposals, which larger amount of funds for salaries.

Incoming oral presentations at international conferences

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Although the funding context is quite intense, several presentations in international conferences will be provided this year.
1. March 14th-16th, 2022: T. Derrien, invited oral presentation in FemtoMat, Mauterndorf, Austria. Main topic this year will be dealing with band structure modification during laser irradiation.
2. March 14th-18th, 2022: collaborator assoc. prof. M. Kozak will present results of joint collaboration on high harmonic generation at DPG meeting (Erlangen).
3. April, 6th-7th 2022: T. Derrien, oral presentation at SPIE Photonics EU, Strasbourg, France.
4. May 30th – June 3rd, 2022: Prof. N. M. Bulgakova will present a work on energy absorption and redistribution channels in silicon, that includes some TDDFT results from our group. EMRS Spring Meeting 2022.
5. September 11th-16th, 2022 [CANCELED]: T. Derrien, invited oral presentation at ALT22, Arcachon, France. The topic of Arcachon conference remains to be defined.

Edit: due to geopolitical context, my invited oral presentation of ALT22 is now canceled.

Invited webinar on Marie Curie Individual Fellowship and RISE programs

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On Wed. 9th Feb., T. Derrien delivered an invited presentation at the webinar “Why do researchers need to be mobile?”, organized by the Mendel University (Brno, Czech Republic) in context of the EU project “ASFORCLIC”. The webinar also included a presentation of Fullbright fellowships (Czech <-> USA exchanges), COST actions and Erasmus+.

As fellow of Marie Curie individual fellowship and main contact of Atlantic project in the Czech Republic, T. Derrien presented the outcomes of the two mobility projects on career development.

New PhD student is joining the group!

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A new student will be joining our group soon. MSc. Ghassan ABER is from Casablanca (Morocco), and he will be working on time-dependent density functional theory. Within the group, he will support the TDDFT activities with comparison to experimental results obtained by various collaborators, along with preparing his PhD thesis at the HiLASE Centre. He will also contribute to the ATLANTIC project. We are very much looking forward!

Electricity prices skyrocket have impacted our HPC activities in January

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The price of electrical energy has been skyrocketing last year. As a result, the cheapest supplier of Czech Republic, Bohemia Energy has now bankrupted, forcing several institutions to transfer their contract to other, more expensive suppliers. Unfortunately, cost for electricity in future will be multiplied by a factor close to 4 (and a factor 10 during the time to negotiate new contracts!), hence impacting the activities in High Power Computation of Czech Republic. Note that similar problems took place in Poland and Norway last months as well.

IT4Innovation, the Czech national supercomputing facility located in Ostrava, has expressed difficulties through their website. On Tuesday, the IT4I users council has met to discuss this extraordinary situation, where mitigation actions were discussed.

Our other computational center, provided by PRACE DECI in Portugal, got an incident due to electrical interruption that has damaged their facility. Finally, the production has restarted in the end of January.

As a result, our high power computation activities have been strongly reduced in second part of January and could partially restart at the end of the month. While our PRACE-DECI project will continue to fully support our activities, it is unlikely that our access to IT4I will be operating again before the end of our project IT4I-OPEN-20th FLAMENCO on March 21st, thus decreasing our number of available core-hours on that project.

Photo-ionization dynamics in solids: our new publication appeared in Physical Review B

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The international team of researchers from the HiLASE Centre, Czech Republic, and the Max Planck Institute for Structure and Dynamics of Matter, Germany, has performed a theoretical study shedding light on the electron dynamics in crystalline semiconductors irradiated by ultrashort laser pulses. Based on first-principles time-dependent density functional theory (TDDFT) implemented on high power computers, the study provides deep insights on the ultrafast laser induced metallization of semiconducting materials. In their work, the scientists performed a comparison of the widely employed Keldysh theory of photoionization and the Drude model describing free carrier optical response with the data of the TDDFT simulations for a wide range of laser irradiation parameters. Although qualitatively a reasonable agreement was obtained, first principle simulations enable quantitative predictions of the photoionization rates and of the absorbed energy within and beyond the validity ranges of the analytical theories.

This work opens new routes for understanding laser-induced phenomena important for the development of novel applications in ultrafast photonics, the field where the band structure of materials can be engineered during their illumination by ultrashort laser pulses. The employed methodology can be used for smart choice of materials to achieve desired transient optical, electronic, and magnetic properties controlled by laser irradiation.

A joint paper on this subject has been recently published in a prestigious journal Physical Review B (Impact Factor of 4.036) of the American Physical Society.

5 oral contributions (incl. 2 invited) were given by the group in the last 3 months

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Since September, the activities of the group were reported in 5 oral presentations at international conferences, including 2 invited talks. 4 of these oral presentations are available on Youtube.

  1. Advanced Laser Technologies (Moscow), 2 presentations from the group (incl. 1 invited).
  2. Ulltrafast Light (Moscow), Invited talk (20 min), 1 invited presentation from the group.
  3. Actual problems in Solid State Physics (Belarus), 2 oral contributions (10 min each), from the group.
  1. T. J.-Y. Derrien, Y. Levy, N.M. Bulgakova,
    Assessment of the time-dependent density functional theory for investigating femtosecond laser energy absorption by metals, invited oral presentation (20 min)
    September 6th, 2021
    Advanced Laser Technologies (ALT21)
    Moscow (online)
    Russian Federation
  2. K. Hlinomaz, Y. Levy, T. Derrien, N. M. Bulgakova
    Numerical Modeling of Thermal Response of Molybdenum Thin Film on Different Substrates Irradiated by Short Laser Pulse (oral presentation, 15 min).
    September 6th, 2021
    Advanced Laser Technologies (ALT21)
    Moscow (online)
    Russian Federation
  3. T. J.-Y. Derrien
    Ultrafast excitation of electrons in crystals: insights from non-equilibrium band structure calculations (invited oral presentation, 20 min)
    October 4th-8th, 2021
    Ultrafast Light (Lebedev Institute)
    Moscow (online)
    Russian Federation
  4. T. J.-Y. Derrien
    Ultrafast excitation of electrons in crystals: insights from non-equilibrium band structure calculations (oral presentation, 10 min)
    November 22nd-26th, 2021
    Actual problems in Solid State Physics (APSSP 2021)
    Minsk (online)
    Belarus
  5. K. Hlinomaz , A. S. Fedotov, I. Timoshchenko, A. Kozlovski, Y. Levy , T. J.-Y. Derrien, V. P. Zhukov, O. G. Romanov, N. M. Bulgakova
    Towards Description of Mechanical Damage of Thin Molybdenum Film upon Pulsed Laser Irradiation (oral presentation, 10 min).
    November 22nd-26th, 2021
    Actual problems in Solid State Physics (APSSP 2021)
    Minsk (online)
    Belarus

Presentation of contributions from Bc. Kristyna Gazdova will be introduced in next conferences.

Springer chapter submitted

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Prof. N. M. Bulgakova has submitted a chapter of 60 pages, 22 figures and 299 references for a book of Springer publishing house being in preparation by editors prof. Razvan Stoian (Laboratoire Hubert Curien) and prof. Jörn Bonse (BAM Berlin).

Dr. T. J.-Y. Derrien and Y. Levy gratefully thank prof. Bulgakova for the kind invitation to contribute jointly to the chapter that has a good probability to be the 1st chapter of the book.

Looking forward!

HPC project PRACE-DECI-17th “Frecuencia” granted our research group with 6.95 million core-hours to be used before September 2022.

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To support quantum modeling activities [based on the time-dependent density functional theory (TDDFT)] of the Department of Scientific Laser Applications, the group of Ultrafast Photonics led by T. J.-Y. Derrien obtained today 6.95 millions core-hours of computational time in one of the supercomputers of the PRACE EU network (project FRECUENCIA).

Along with the IT4I.cz project FLAMENCO (3.8 million core-hours), this computational time will be employed for resolving the dynamics of electrons in solid materials upon ultrashort laser irradiation in various experimental situations. The project also aims at testing the tools for employing more effective formalisms for the study of laser-matter interaction in future.