Mid-IR frequency combs enabled by semiconductor saturable absorption mirrors (SESAMs)

CNRS C2N; France; Sur place; EUR 40 000 - 60 000; Plein temps

Résumé du poste

A renowned research center in France seeks a Postdoc to join their Quantum Devices Team specializing in novel optoelectronic devices. The role involves developing mode-locked lasers and SESAMs while engaging in significant scientific research and collaboration with leading labs. A PhD in Physics, Optics, or Engineering is required, and the position offers negotiable salary based on experience. Applications should be sent to Raffaele Colombelli via email.

Qualifications

• Highly motivated candidates with experience in semiconductor device physics.
• Experience in quantum and electromagnetic simulations for device design.
• Background in optoelectronic characterization techniques.

Responsabilités

• Develop self-starting passively mode-locked compact lasers.
• Work on SESAMs with controllable figures of merit.
• Study, achieve, and demonstrate mode-locking and related applications.

Connaissances

Physics and technology of semiconductor devices

Electromagnetic modeling

Cleanroom manufacturing

Laser physics

Optoelectronic characterization techniques

Design of quantum hetero-structures

Formation

PhD in Physics

PhD in Optics

PhD in Engineering

Description du poste

Organisation/Company CNRS C2N Department Photonique Research Field Physics » Optics Physics » Quantum mechanics Physics » Applied physics Physics » Solid state physics Engineering » Electrical engineering Researcher Profile First Stage Researcher (R1) Recognised Researcher (R2) Established Researcher (R3) Positions Postdoc Positions Country France Application Deadline 30 Jan 2026 - 00:00 (Europe/Paris) Type of Contract Temporary Job Status Full-time Hours Per Week 40 Offer Starting Date 2 Feb 2026 Is the job funded through the EU Research Framework Programme? Horizon Europe - ERC Reference Number 101095959 Is the Job related to staff position within a Research Infrastructure? No

Offer Description

We have an opening for a two-year (initially) post-doctoral appointment at University Paris Saclay (France) and CNRS, with the Centre for Nanosciences and Nanotechnologies (C2N). You will integrate the Mid-IR /
THz Quantum Devices Team, specialized in the development of novel optoelectronic devices exploiting quantum
electro-dynamic effects at mid-infrared wavelengths [1] [2].
Located south of Paris, University Paris Saclay extends across a vast local area and is ranked as France’s top university. The salary level can be negotiated depending on the candidate experience. The project is supported by an ERC Advanced Grant (project SMART-QDEV).

The goal of this project is to develop self-starting passively mode-locked compact lasers with ps pulses, enabled
by novel semiconductor saturable absorption mirrors (SESAM [3]) covering the whole mid-IR [4]. Compact lasers
mean semiconductor-based lasers, or fiber based lasers.

Scientific project: Saturation of the light-matter interaction is a general nonlinear feature of material systems, be
they atoms or semiconductors [5]. A saturable absorber exhibits an absorption coefficient that depends on the
incident intensity. In semiconductors, controlling saturation phenomena is of importance for fundamental physics
as well as applications. A seminal example is the semiconductor saturable absorption mirror (SESAM) [6] [3] based
on interband transitions in quantum wells. It revolutionized the ultra-fast lasers in the vis/near-IR spectral range,
allowing ultra-fast laser pulses and frequency combs that find applications in many domains.
In the mid-IR (3-30 um), the intensity required to reach saturation is very high, about 1 MW/cm2. This very high value
explains why effective SESAM mirrors do not exist in the mid-IR yet.

The project aims at generating mid-IR frequency combs with tabletop interband/quantum cascade lasers, relying
on SESAMs with controllable figures of merit (saturation intensities, non-saturable losses…). And also developing
initial applications

The activity builds on recent results of the Host Team that elucidated how absorption saturation (and also
coherent/incoherent non-linearities) can be engineered if the system operates in the strong light-matter coupling
regime [7]. The Team also provided initial experimental proof of the validity of the concept [8]. The key is that in
the strong coupling regime, the response of the system is governed by coupled light-matter states called
polaritons [9] [10]. Operating in the strong coupling regime is crucial to the device functionality: the intrinsic speed
of intersubband polaritons [11] [12] and their enhanced non-linearities make them an ideal platform to
implement ultra-fast devices for the mid-IR, that is an underlying research thrust in the Host Team.

This rich physics permits the development of several device families, even beyond this post-doc proposal, but all in
development in the Host Team.
The post-doctoral project will evolve in this context. As a post-doc, you will first identify suitable target laser systems (QCL and ICL mainly). After this you will focus on developing and validating SESAMs with figure of merits adapted to such lasers. In particular, the various figures of merit of the devices (saturation fluence, non-saturable losses, speed…) will be carefully gauged. Finally, the laser + SESAM system will be implemented in order to study/achieve/demonstrate mode-locking, and related applications (dual comb spectroscopy for instance) will be explored. Some effort will be also devoted to the implementation of tools and measurement benches for frequency combs characterization in the mid-infrared. Such tools will be also shared with other research lines in the team.

See the attached .pdf document for full details.

The successful applicant will have completed an experimental PhD program in Physics, Optics or Engineering. The position is available immediately. Applications, including cover letter and a CV, should be sent by email to Raffaele Colombelli (E-mail: [e-mail] or [e-mail] ).

References:

[1] M. Malerba, M. Jeannin, S. Pirotta, L. Li, A. G. Davies, E. Linfield, A. Bousseksou, J.-M. Manceau, and R. Colombelli, Appl. Phys. Lett. 119, 181102 (2021).
[2] E. Cortese, N. L. Tran, J. M. Manceau, A. Bousseksou, I. Carusotto, G. Biasiol, R. Colombelli, and S. De Liberato, Nat. Phys. 17, 31 (2021).
[3] U. Keller, Nature 424, 831 (2003).
[4] M. Jeannin, E. Cosentino, S. Pirotta, M. Malerba, G. Biasiol, J. M. Manceau, and R. Colombelli, Appl. Phys. Lett. 122, 241107 (2023).
[5] R. Boyd, Nonlinear Optics, 3rd Edition | Robert Boyd | ISBN 9780123694706 (Academic Press, 2008).
[6] U. Keller, D. A. B. Miller, G. D. Boyd, T. H. Chiu, J. F. Ferguson, and M. T. Asom, Opt. Lett. 17, 505 (1992).
[7] M. Jeannin, J. M. Manceau, and R. Colombelli, Phys. Rev. Lett. 127, 187401 (2021).
[8] M. Jeannin, E. Cosentino, S. Pirotta, M. Malerba, G. Biasiol, J.-M. Manceau, and R. Colombelli, Appl. Phys. Lett. 122, (2023).
[9] D. Bajoni, J. Phys. D Appl. Phys. 45, 313001 (2012).
[10] J.-M. Manceau, S. Zanotto, T. Ongarello, L. Sorba, A. Tredicucci, G. Biasiol, and R. Colombelli, Appl. Phys. Lett. 105, 81105 (2014).
[11] S. Zanotto, R. Degl’Innocenti, J. H. Xu, L. Sorba, A. Tredicucci, and G. Biasiol, Phys. Rev. B - Condens. Matter Mater. Phys. 86, 201302 (2012).
[12] M. Knorr, J. M. Manceau, J. Mornhinweg, J. Nespolo, G. Biasiol, N. L. Tran, M. Malerba, P. Goulain, X. Lafosse, M. Jeannin, M. Stefinger, I. Carusotto, C. Lange, R. Colombelli, and R. Huber, Phys. Rev. Lett. 128, 247401 (2022).

Where to apply

E-mail [e-mail]

Requirements

Research Field Physics » Solid state physics Education Level PhD or equivalent

Research Field Physics » Applied physics Education Level PhD or equivalent

Research Field Physics » Quantum mechanics Education Level PhD or equivalent

Research Field Physics » Condensed matter properties Education Level PhD or equivalent

Skills/Qualifications

The work is experimental, but with an important part devoted to quantum/ electromagnetic simulations for device design. We are looking for highly motivated candidates with experience in some (not necessarily all) of the following fields: physics and technology of semiconductor devices; electromagnetic modeling; cleanroom manufacturing; laser physics; optoelectronic characterization techniques; design of quantum hetero-structures.

The successful applicant will have completed an experimental PhD program in Physics, Optics or Engineering. The position is available immediately.

Specific Requirements

Consortium and Funding: This project will benefit from collaborations with the laboratories IES (Montpellier), LPA/ENS (France), TU Wien (Austria), Laboratory CORIA/CNRS (Rouen), Le Verre Fluoré.
Funding is provided by an ERC Advanced Grant.

The salary level can be negotiated depending on the candidate experience. The project is supported by an ERC Advanced Grant (project SMART-QDEV).