(M/F) – Postdoctoral Research in Optoelectronic Components for High-Repetition-Rate Ultrafast Fiber Lasers

Job Description

Missions

This postdoctoral position is part of an interdisciplinary research project involving two teams at the University of Lille with complementary expertise, from the PhLAM laboratory (Physics of Lasers, Atoms and Molecules) and the IEMN (Institute of Electronics, Microelectronics and Nanotechnology). The goal is to develop a new class of semiconductor saturable absorbers (SESAMs) for ultrashort pulse, high-repetition-rate fiber lasers.

The core objective of the project is to model, design, and test ultrafast semiconductor structures capable of functioning as saturable absorbers—a key element for passive mode-locking in pulsed lasers [1], [2]. These structures will then be integrated into fiber laser cavities to evaluate their dynamic performance.

The major innovation of the project lies in the development of electrically tunable saturable absorbers: by applying a high-frequency RF electric field (up to several tens of GHz), the absorption properties of the component can be dynamically modulated via the Franz–Keldysh effect [3]. This modulation would ultimately enable active locking of the laser repetition rate to an external RF reference, opening new avenues in optoelectronic synchronization technologies, particularly for applications in telecommunications, metrology, and the generation of ultrahigh spectral purity signals.

This approach, based on fast temporal modulation of the effective bandgap in semiconductors, builds upon prior work on using the Franz–Keldysh effect for the detection of ultrafast signals [4]. The current project aims to extend this technique to the domain of mode-locked fiber lasers.

References
[1] U. Keller, “Recent developments in compact ultrafast lasers,” Nature, vol. 424, no. 6950, pp. 831–838, 2003.
[2] M. E. Fermann and I. Hartl, “Ultrafast fibre lasers,” Nature Photonics, vol. 7, no. 11, pp. 868–874, 2013.
[3] Y. Yacoby, “High-Frequency Franz-Keldysh Effect,” Physical Review, vol. 169, no. 3, pp. 610–619, 1968.
[4] J. F. Lampin, L. Desplanque, and F. Mollot, “Detection of picosecond electrical pulses using the intrinsic Franz-Keldysh effect,” Applied Physics Letters, 2001.

Activity

The recruited postdoctoral researcher will serve as the liaison between the two research teams, and will be responsible for:

- Electro-optical modeling of the components,

-Characterization of the fabricated devices,

-Integration and testing of the components within fiber laser cavities.

Your Profil

Skills

Candidates must hold a PhD in Physics, Photonics, or Electronics, with strong knowledge and proven experience in experimental physics and instrumentation.

Your Work Environment

The work will be carried out mainly within the THz Photonics group at the Institute of Electronics, Microelectronics and Nanotechnology (IEMN) [https://www.iemn.fr/], located near the University of Lille campus. The postdoctoral fellow will work under the supervision of Dr. Emilien Peytavit

Compensation and benefits

Compensation

2500 € net

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions