Surface nanostructuring of various materials exposed to intense extreme ultraviolet and X-ray radiation
Project ID:GA14-29772S
Provider:Czech Science Foundation
Period:Jan 01, 2014 - Dec 31, 2016
Recipient -- coordinator:Institute of Physics of the CAS, v. v. i.
-- Ing. Libor Juha, CSc.
Co-recepient(s) / PI(s):Institute of Plasma Physics, Czech Academy of Sciences, Prague -- RNDr. Karel Koláček, CSc.
Co-investigators from IPPA. Frolov, V. Prukner, J. Schmidt, J. Štraus

Aims of the project: The new sources of intense coherent short-wavelength radiation, i.e., plasma and e-beam based XUV/X-ray lasers, represent promising tools for the direct nano-patterning of solids, as they enable the ablation (desorption) printing of features with dimensions comparable to the wavelength. A key advantage of the XUV/X-ray lasers for fabrication of tailored nanostructures is the unique combination of exceptionally short wavelength, very good coherence, and high peak power. Certain thresholds for materials processing require XUV/X-ray sources to deliver enough fluence and thus sufficiently high power to the irradiated surface area. Although high-order harmonics and non-coherent sources developed for EUV lithography can also pattern material surfaces with nanometer precision, they cannot directly produce threedimensional nanostructures using a few shots in a single processing step. In this project, a systematic investigation of spontaneously grown(LIPSS) and externally created (mask projection) nano-patterns on XUV/X-ray laser-irradiated surfaces is proposed.

Progress/Results: The research started (according to schedule) with metrology of XUV laser pulse – focused on energy measurements of laser pulse, on divergence of laser beam, and on reflectivity of focusing mirror. The energy of laser pulse was measured by the vacuum photodiode (of our own construction) with gold photocathode closely spaced behind anode grid. The new calibration procedure is based on tabulated photoemission efficiency of gold and on measured transmission of Al filters, of collection efficiency of the anode, and of damping of the measuring cable. It turned out that the typical energy of laser pulse generated by our 400 mm long capillary at ~20 kA discharge current is ~0.8-1 mJ, while energy of the same capillary at ~40 kA is ~40 mJ. This is the highest energy achieved at this wavelength in the world. The reflectivity of our multilayer (Sc/Si) mirror at quasi-normal incidence was measured to be 22.5%. The divergence of laser beam was calculated from the beam profiles of the beam spots on fluorescence screen registered in two distances (570 and 1180 mm) from the capillary mouth and it was found to be 2,07 ± 0,17 mrad for 232 mm long capillary, and 2,59 ± 0,30 mrad for 400 mm long capillary. The shape of the focused beam was investigated also with the help of ablation spots. Among others it was found that there is a large astigmatism with astigmatic difference as large as ~16 mm. Recently the series of ablation imprints registered in front of tangential focus was analysed by atomic force microscope; this experimentally obtained z-scan was fed into a numerical code simulating the laser beam propagation. One of results of this simulation is astigmatic difference close to our experimentally obtained value. The difference between routine and high-energy regime of laser operation was also demonstrated by ablation plumes (ejections of glowing clouds of emitting particles) from surfaces of solid targets.


Štraus J., Koláček K., Schmidt J., Frolov O., Vilémová M., Matějíček J., Jäger A., Juha L., Toufarová M., Choukorov A., Kasuya K.: Response of fusion plasma-facing materials to nanosecond pulses of extreme ultraviolet radiation. Laser and Particle Beams 36 [3] (2018) 293-307. [ Abstract ] [ Link ]

Makhotkin I.A., Sobierajski R., Chalupský J., Tiedtke K., de Vries G., Stoermer M., Scholze F., Siewert F., van de Kruijs R.W.E., Louis E., Jacyna I., Jurek M., Klinger D., Nittler L., Syryanyy Y., Juha L., Hájková V., Vozda V., Burian T., Saksl K., Faatz B., Keitel B., Ploenjes E., Schreiber S., Toleikis S., Loch R., Hermann M., Strobel S., Nienhuys H.-K., Gwalt G., Mey T., Enkisch H.: Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold. Journal of Synchrotron Radiation 25 [1] (2018) 77-84. [ Abstract ] [ Link ]
[Workshop on FEL Photon Diagnostics, Instrumentation and Beamline Design (PhotonDiag2017). Stanford, 01.05.2017-03.05.2017]

Toufarová M., Hájková V., Chalupský J., Burian T., Vacík J., Vorlíček V., Vyšín L., Gaudin J., Medvedev N., Ziaja B., Nagasono M., Yabashi M., Sobierajski R., Krzywinski J., Sinn H., Störmer M., Koláček K., Tiedtke K., Toleikis S., Juha L.: Contrasting behavior of covalent and molecular carbon allotropes exposed to extreme ultraviolet and soft x-ray free-electron laser radiation. Physical Review B 96 [21] (2017) 1-11, č. článku 214101. [ Abstract ] [ Link ]

Kasuya K., Motokoshi S., Taniguchi S., Nakai M., Tokunaga K., Koláček K., Schmidt J., Frolov O., Štraus J., Matějíček J., Choukourov A.: Ablation-erosion analyses of various fusion material surfaces and developments of surface erosion monitors for notification of fusion chamber maintenance times, as an example: Visible light transparent SiC and up-conversion phosphors applied to plasma facing surface structures, useful for versatile purposes to protect and diagnose fusion chambers and so on. Proceedings of SPIE, Vol. 10254: XXI INTERNATIONAL SYMPOSIUM ON HIGH POWER LASER SYSTEMS AND APPLICATIONS 2016. Bellingham: SPIE, 2017 - (Schuocker, D.; Majer, R.; Brunnbauer, J.), č. článku 102541B. SPIE. ISBN 978-1-5106-1009-5. ISSN 0277-786X. [ Abstract ] [ Link ]
[International Symposium on High Power Laser Systems and Applications 2016/21./. Gmunden (AT), 05.09.2016-09.09.2016]

Koláček K., Schmidt J., Štraus J., Frolov O., Juha L., Chalupský J.: Interaction of Extreme Ultraviolet Laser Radiation with Solid Surface: Ablation, Desorption, Nanostructuring. Proceeding of SPIE Vol. 9255: 20th International Symposium on High Power Systems and Applications 2014, HPLS and A 2014. Vol. 9255. Bellingham : SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Tang, C.; Chen, S.; Tang, X.), 92553U-92553U ISBN 978-1-62841-322-9. ISSN 0277-786X. - (SPIE. 9255). [ Abstract ] [ Link ]
[International Symposium on High Power Laser Systems and Applications 2014/20./. Chengdu (CN), 25.08.2014-29.08.2014]

Frolov O., Koláček K., Schmidt J., Štraus J., Choukourov A., Kasuya K.: EUV nanosecond laser ablation of silicon carbide, tungsten and molybdenum. Conference proceedings of 9th International Conference on Reactive Plasmas, 68th Gaseous Electronics Conference and 33rd Symposium on Plasma Processing. Meieki, Nakamura-ku, Nagoya : Japan Society of Applied Physics, 2015 - (Toyoda, H.; Vukovic, M.), GT1.00124-GT1.00124 ISBN 978-4-86348-529-7. - (APS Meeting). [ Abstract ]
[International Conference on Reactive Plasmas, 68th Gaseous Electronics Conference and 33rd Symposium on Plasma Processing/9./. Honolulu, Hawaii (US), 12.10.2015-16.10.2015]

Schmidt J., Štraus J., Koláček K., Frolov O.: Nanostructuring of solid surfaces by discharge-pumped xuv laser source. NANOCON 2015: 7th International Conference, Papers - Full Texts. Ostrava : TANGER, spol. s r.o, 2015 - (Shrbená, J.; Zbořil, R.) ISBN 978-80-87294-59-8. [ Abstract ]
[NANOCON 2015. International Conference /7./. Brno (CZ), 14.10.2015-16.10.2015]

Schmidt J., Koláček K., Frolov O., Štraus J., Choukourov A.: Soft X-ray source based on the high-current capillary-discharge system. Proceedings of SPIE Volume 9589; X-ray Lasers and Coherent X-ray Sources: Development and Applications XI. Vol. 9589. Bellingham : SPIE-INT SOC OPTICAL ENGINEERING, 2015 - (Klisnick, A.; Menoni, C.), "958911-1-958911-6" ISBN 978-1-62841-755-5. ISSN 0277-786X. - (SPIE. 9589). [ Abstract ] [ Link ]
[SPIE Conference : X-Ray Lasers and Coherent X-Ray Sources: Development and Applications XI. San Diego, CA (US), 12.08.2015-13.08.2015]

Schmidt J., Koláček K., Frolov O., Štraus J.: XUV Source Based on the Fast High-Current Capillary-Discharge System. Proceedings of the 2014 IEEE International Power Modulator and High Voltage Conference, IPMHVC 2014. Santa Fe : IEEE, Institute of Electrical and Electronics Engineers Inc, 2015 - (Garner, A.), s. 360-362 ISBN 978-1-4673-7323-4. - (IEEE). [ Abstract ] [ Link ]
[IEEE International Power Modulator and High Voltage Conference, IPMHVC 2014. Santa Fe (US), 01.06.2014-05.06.2014]

Frolov O., Koláček K., Schmidt J., Štraus J.: Ablation Plume Induced by Laser Euv Radiation. X-Ray Lasers 2014: Proceedings of the 14th International Conference on X-Ray Lasers. Springer International Publishing, 2015 - (Rocca, J.; Menoni, C.; Marconi, M.), s. 397-403 - (Springer Proceedings in Physics. 169). [ Abstract ] [ Link ]
[International Conference on X-Ray Lasers/14./. Fort Collins, Colorado (US), 26.05.2014-30.05.2014]