Download ED 397 projet de thèse QCL 2016

'Physique et Chimie des Matériaux' – ED 397 – 2016
Proposition pour allocation de recherche, Thème (A,B,C,D,E): D
retour impératif avant le vendredi 18 mars 2016 à 12h à : [email protected],
en format PDF exclusivement
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Unité de recherche (nom, label, équipe interne) : Laboratoire Pierre Aigrain UMR 8551
Adresse : Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris
Directeur de l’Unité : Jean-Marc BERROIR
Etablissement de rattachement : ENS/CNRS/UPMC/UPD
Nom du directeur de thèse (HDR), téléphone et courriel : Jérôme TIGNON (UPMC), 06 16 92 86 63,
[email protected]
Nombre de thésards actuellement encadrés et années de fin de thèse (*: ligne à renseigner
obligatoirement) : 2 thésards, fin des thèses été 2016 (en co-encadrement).
Co-encadrant éventuel : Sukhdeep DHILLON (CNRS)
Titre de la thèse : Ultra-short pulses and Frequency Combs in Quantum Cascade Lasers
Description du projet (max. 1 page) :
Modelocking is the exemplar method for the generation of ultra-short laser pulses and frequency
combs. It has revolutionized technology in the visible and near-infrared, and touches a range of
applications from spectroscopy to cold atoms. A benchmark system for such studies is the
modelocked Ti:Sapphire laser, which has grown from being a laboratory curiosity to an essential
tool in a broad range of application sectors. Beyond Ti:Sapphire systems, there have been
impressive developments in semiconductor based devices for pulse generation in the optical
range. These benefit from low system costs and are an enabling technology in new application
domains including high speed communications. Nonetheless semiconductor modelocking in other
spectral ranges such as the terahertz (THz) and mid-infrared (MIR) has proven to be
challenging, despite potential applications extending from coherent control to metrology.
This proposition consists in the study of ultrashort pulse generation in Quantum Cascade Lasers
(QCLs). QCLs are promising semiconductor based sources that operate in the MIR and THz
regions. In these devices laser action is based on electronic intersubband transitions within a
series of quantum wells and a "cascade" where the electrons undergo multiple transitions
through many periods of the quantum system. These two concepts have permitted powerful and
compact sources in previously inaccessible electromagnetic regions. However, their unique
ultrafast dynamics have been thought to limit the possibility of pulse generation and
modelocking.
Our group has demonstrated recently that this is not the case and that pulses can be generated
from QCLs using active modelocking. However the pulse durations are inherently limited to
~10ps with current techniques. The project will consist in the introduction of new concepts in
modelocking to realise a reduction in pulse widths and for the high power pulses in a compact
semiconductor system. This will include the coupling of passive and active pulse generation
techniques and apply ultrafast switching techniques to take advantage of the QCL’s fast
dynamics. This will permit the generation of high peak powers and chip based frequency combs
in the THz and MIR spectral regions. The expected advances will allow perspectives of chip
based systems for high resolution dual comb spectroscopy.