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MASTER | Ecriture laser 3D pour l’integration de nouvelles fonctionnalités dans les composants silicium - 3D microfabrication with infrared femtosecond lasers inside silicon

In the past two decades, direct femtosecond laser writing has emerged as an attractive way for microfabrication inside transparent dielectrics. Focused to small focal spots, visible light pulses make possible to form directly microscale three-dimensional 3D optical elements in bulk dielectrics (e.g. writing of waveguides, optical memories, …). Using infrared tunable ultrafast lasers, a major objective of our research is to extend these possibilities to semiconductors that are opaque to visible light [1]. This must open the way to fabricate by laser writing silicon micro-devices with hybrid functionalities (electronic, fluidic and optical [2]).

Experimental setup of using 60-femtosecond laser pulses for laser writing in silicon. Credit : [1]

This master thesis addresses scientific questions related to extreme spatio-temporal localization of intense laser radiations in condensed matter [1,3]. The student will initially take over ongoing work into fundamental aspects of the interaction of mid‐infrared short laser pulses with semiconductor materials (including silicon). This experimental work relies on a pump-and-probe microscopy setup directed at understanding and controlling ultrafast optical breakdown and permanent modifications inside bulk silicon [1,4]. The student will be also in charge of the design and assembly of an experiment to enhance the conditions of excitation inside the materials. The experimental arrangement will deliver tightly focused burst of femtosecond pulses to observe the combined effects of several pulses inside matter. This interaction must lead to confined “micro-explosions” associated to pressure (10TPa) and temperature conditions that are not accessible by any other method. It will allow to study a wide range of modifications up to drastic transformations. These studies will pave the way toward the direct laser writing of three-dimensional optical or microfluidic devices. They may also open the possibility for the synthesis of superdense crystallographic phases of silicon with novel and exotic properties.

[1] M. Chanal., V. Yu Fedorov, M. Chambonneau, R. Clady, O. Utéza, S.Tzortzakis, D. Grojo, Crossing the threshold of ultrafast laser writing in bulk silicon, Nature Communications 8 (2017) 773
[2] M. Chambonneau, Q. Li, M. Chanal, N. Sanner, D. Grojo, Writing waveguides inside monolithic crystalline silicon with nanosecond laser pulses, Optics Letters 41 (2016) 4875
[3] V. Yu. Fedorov, M. Chanal, D. Grojo, S. Tzortzakis, Accessing extreme spatio-temporal localization of high power laser radiation through transformation optics and scalar wave equations, Physical Review Letters 117 (2016) 043902
[4] A. Mouskeftaras, M. Chanal, M. Chambonneau, R. Clady, O. Utéza, D. Grojo, Direct measurement of ambipolar diffusion in bulk silicon by ultrafast infrared imaging of laser-induced microplasmas, Applied Physics Letters 108 (2016) 041107

Keywords : Laser Science and Technologies, Ultrafast optics, Laser Physics, Non-linear optics, Laser-matter interactions, Advanced microscopy

Contact : David GROJO,

Additional information : *Monthly allowance for the duration of the MS thesis : > 550 Euros *Open PhD position : This work will be conducted in the framework of a recently funded ERC project (European Research Council). An excellent candidate will have the possibility to be funded for a PhD after the MS thesis.

Description of MSc Thesis - 571.3 ko