High-peak-power electro-optic frequency combs for mid-infrared generation

Organisation/Company Université de Rouen Normandie Research Field Physics » Optics Researcher Profile First Stage Researcher (R1) Positions PhD Positions Application Deadline 1 Jun 2026 - 12:00 (Europe/Paris) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 35 Offer Starting Date 1 Oct 2026 Is the job funded through the EU Research Framework Programme? Not funded by a EU programme Is the Job related to staff position within a Research Infrastructure? No

Offer Description

The CORIA laboratory opens a PhD position in the field of ultrafast optics.

Optical frequency combs are key tools for broadband precision spectroscopy, particularly in the mid infrared (MIR), where strong molecular absorption bands enable sensitive multi‑species detection (1). However, direct MIR comb generation remains technically demanding, motivating approaches based on nonlinear conversion of near‑infrared combs (2). Electro‑optic (EO) frequency combs are especially attractive due to their intrinsic coherence, stability, and flexible repetition rates from MHz to tens of GHz, but their relatively long pulse durations and low peak powers currently limit their efficiency for nonlinear spectral conversion (3).

This PhD project aims to overcome these limitations by developing high‑peak‑power EO combs optimized for broadband MIR generation. The work will combine fiber amplification, dispersion engineering, spectral broadening in fibers, and nonlinear temporal compression to reach sub‑100 fs pulse durations with multi‑kilowatt peak powers. These optimized combs will then be used to generate coherent MIR spectra through nonlinear processes such as difference‑frequency generation in PPLN crystals. The project benefits from an operational electro‑optic dual‑comb spectroscopy platform at 1.55 µm developed at CORIA, together with established expertise in source technologies including optical parametric oscillators, MIR fiber lasers and nonlinear frequency conversion in optical waveguides (4–7). This environment provides a strong foundation for developing high‑peak‑power electro‑optic comb architectures for broadband mid‑infrared generation and their application to high‑speed spectroscopic diagnostics, including combustion analysis and multi‑species gas sensing.

Job profile

The candidate will develop and characterize electro‑optic frequency comb sources and implement nonlinear compression and MIR conversion experiments. The project involves ultrafast optics, nonlinear optics and spectroscopy. A strong background in optics/photonics and numerical skills (Python/Matlab modeling appreciated) is expected.