PhD Thesis Quantum optics with hBN single-photon sources in top-down photonic devices (M/F)

Job Description

Thesis Subject

Optically active deep defects in the solid state (or color centers) can be seen as artificial atoms. They represent a major interest in quantum information science, owing to their potential as single photon emitters and their possible integration in nanostructures and devices. Emblematic examples include nitrogen-vacancy centers in diamond, at the basis of emerging quantum networks. In the last few years, color centers in the 2D material hexagonal boron nitride (hBN) have established them-selves as excellent quantum emitters, bringing new perspectives of applications to on-chip quantum technologies.
The PhD thesis will take place in the GEMaC laboratory (UVSQ/CNRS) located in Versailles. In the Quantum Nanophotonics team, we have recently demonstrated a new family of single photon emit-ters in hBN with excellent properties in terms of brightness, coherence and reproducibility. These emitters can be locally created using an electron beam in a scanning electron microscope, which has allowed us to demonstrate top-down integration in photonic devices.
The thesis is part of ANR project starting in 2025, which builds upon recent experimental demonstrations from the host team and their partners at LPENS (ENS Paris) and LPEM (ESPCI) to develop a new generation of top-down quantum photonic devices based on single-photon emitters and superconducting detectors integrated into cavities and waveguides for applications to optical quantum information.
In this context, the PhD project will consist of optical characterization and quantum optics experiments based on single-photon sources integrated into hBN monolithic photonic devices, consisting of a microcavity coupled to a waveguide. These experimental studies will be based on photoluminescence and resonant laser excitation, associated with photon counting and interferometry techniques (e.g. Hanbury Brown and Twiss, Hong-Ou-Mandel interferometry), as well as spectroscopy. The results will establish the relevant figures of merit such as quantum coherence, brightness and indistinguishability of the emitter-cavity coupled system, and will be used during the project to improve the device design and fabrication. The ultimate goal is the demonstration of quantum interference of photons emitted by distinct emitters. The experiments will be performed at both room temperature and cryogenic temperature. The candidate is also expected to participate to the sample fabrication, using nanofabrication techniques specific to 2D materials. The project will take place in the QNP team, in collaboration with the project partners at LPENS and LPEM.

Skills
- Master's degree in Physics, Photonics, Quantum Engineering, or related discipline
- strong background in experimental quantum optics or photonics
- experience with optical setups, spectroscopy, or laser instrumentation is appreciated
- programming skills for data acquisition and analysis (Python)
- interest in quantum technologies and solid-state quantum emitters.
- strong motivation for experimental research, autonomy, scientific curiosity and rigor. Good communication skills and proficiency in English are required.

Your Work Environment

The GEMaC (UMR8635 CNRS/UVSQ) designs and/or studies materials with novel properties. This requires expertise in material synthesis, advanced characterization, physical property studies, as well as modeling and theoretical description. Instrumental development is also a significant part of its activities.
GEMaC has approximately 45 people across 3 thematic axes, including the NPQ (QNP) axis, 1 technical platform, and 2 shared services.

The activity of the Research axis 3 falls into the domain of quantum nanophotonics. We are first interested in nanosources of light:
- colloidal semiconductor nanocrystals based on CdSe, at the single object level or self-assembled into aggregates,
- colour centres in wide bandgap semiconductor nanostructures (ZnO, hBN, SiC),
- low dimensional hybrid perovskites.
We are also studying their coupling to photonic structures, in particular plasmonic structures, whose resonances are confined within a few nanometres.
The equipment and experimental setups for quantum optics experiments (lasers, cryostats, sensitive detectors, spectrometers, etc.) are already in place. Any necessary modifications will be funded by the ANR project.
Training will be funded in particular through the unit's specific training plan. Fieldwork will be funded by the ANR project.
In general, the PhD student will adhere to the laboratory's internal regulations. They will be subject to enhanced medical monitoring. They will also undertake in-house laser training and on-the-job training.

Constraints and risks

The position involves laser and cryogenic hazards. Specific training will be provided.

Compensation and benefits

Compensation

2300 € gross monthly

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