Envisaged funding: 3-year Public funding
Application deadline: May 1st, 2018
Start date of the proposed thesis: October 2018
Place: Laboratoire Hubert Curien UMR CNRS 5516
18 Rue du professeur Benoit Lauras
42 000 SAINT-ETIENNE, FRANCE
Subject of the thesis:
Laser-induced surface or bulk nanostructuring is nowadays a common tool for material functionalization that opened wide fields of applications including the fabrication of optically and visually enhanced substrates. A complete understanding of physico-chemical reactions involved in material nanotexturing appears as crucial in terms of process optimization but is still challenging, especially in chemically and structurally changing media for which the dynamics may involve several time scales. For such complex systems, using time-resolved optical techniques naturally appears as a versatile way to disentangle the different chemical and physical transient reactions triggered by laser-matter interaction.
We have recently demonstrated that femtosecond (fs) laser irradiations can lead to the formation of 3D self-organized systems, effectively combining buried sub-wavelength metallic NP gratings and periodic surface structures. This strategy of 3D laser-induced self-organization paves the way for a new generation of nanostructuring processes, in which composite multilayer stacks could be designed to sustain guided waves in specific layers and provide self-organization of NPs at pre-defined depths. Applications of such systems can be found in diffractive and polarization-sensitive optics, with great promise for high-density optical image encoding and security.
In this PhD thesis we aim to develop innovative characterization techniques to probe in situ and at different time scales from the fs to the second, the chemical, physical and optical mechanisms behind the laser-induced self-organization processes. The ultrafast dynamics of metallic NPs has always been investigated with a controlled temperature rise to avoid modifying the system irreversibly. One of the main challenges of the thesis is to carry out in operando time-resolved spectroscopic characterizations of the self-organization process from the fs to the second timescale to better describe the mechanisms involved, from charge transfers to coalescence and ripening mechanisms triggered by the temperature rise.
The PhD student may also be involved in an active collaboration with the Lawrence Berkeley National Laboratory (LBNL), CA, USA, to contribute to the development of experiments on synchrotron sources enabling the implementation of complementary time-resolved electron characterizations. This will provide new information and a better understanding of the fundamental mechanisms operating in these transformation processes of metallic nanoparticles under laser irradiation.
This subject opens the way to new and remarkable experimental progresses and provides additional support to the development of applications with strong potential in the field of security, which will interest our industrial partner HID Global CID.
(1) D. Babonneau, D. Diop, L. Simonot, B. Lamongie, N. Blanc, N. Boudet, F. Vocanson, N. Destouches, "Real-time investigations of structural and optical changes in photochromic Ag/TiO2 nanocomposite thin films under laser irradiation", NanoFutures, 2, 015002, 13 p (2018)
(2) Z. Liu, J. Siegel, M. Garcia-Lechuga, T. Epicier, Y. Lefkir, S. Reynaud, M. Bugnet, F. Vocanson, J. Solis, G. Vitrant, N. Destouches, "3D self-organization in nanocomposite layered systems by ultrafast laser pulses", ACS Nano, 11 (5), 5031–5040 (2017)
(3) S. Bakhti, A. V. Tishchenko, X. Zambrana-Puyalto, N. Bonod, S. Dhuey, P. J. Schuck, S. Cabrini, S. Alayoglu, N. Destouches, "Fano-like resonance emerging from magnetic and electric plasmon mode coupling in small arrays of gold particles", Scientific Reports, 6, 32061, 1-12 (2016)
Considered experimental techniques:
Ultrafast laser irradiation, time-resolved pump-probe spectroscopy on plasmonic nanomaterials, microscopy (optical, scanning and transmission electron).
This experimental PhD project is suitable for applicants graduated with a master degree or an equivalent training in physics, nanophotonics, photonics, optics or related topics. Good level in English is required. The PhD candidate should have a strong motivation to answer the most important questions of the fundamental laser-induced physics and chemistry of metallic nanoparticles in thin films. He (she) should have a solid background in physics to carry out experimental research using and developing ultrafast laser instrumentation, spectroscopy, microscopy, modelling of plasmonic systems and data analysis. The ability of taking initiatives and to work with autonomy is compulsory to correctly carry out this thesis, while relying on the skills of the different people involved in the project.
Please send us your CV with a possible list of publications and conferences, a motivation letter, your Bachelor and License transcripts and references or a recommendation letter, as soon as possible and before May 1st, 2018.
Prof. Nathalie DESTOUCHES and Dr Christophe HUBERT
Laboratoire Hubert Curien
Université de Lyon, Université Jean Monnet
phone: 04 77 91 58 23
email: email@example.com , firstname.lastname@example.org