A career spanning the CEA ecosystem
After graduating from the École Nationale Supérieure de Physique de Grenoble, Julia Simon completed a research Master's degree in condensed matter and semiconductor physics before pursuing a PhD at the CEA's Fundamental Research Division, where she studied the optical properties of GaN (gallium nitride)-based heterostructures.
Wanting to work on industrially oriented topics, she then joined CEA-Leti, where she spent eight years working on cleanroom manufacturing processes.
She subsequently spent six years at CEA-Liten, managing industrial projects, before returning to CEA-Leti, this time within the optics department, which was reorganizing its research activities around micro-LED technologies for microdisplays.
"I really enjoyed the teamwork during my first time at Leti, and I wanted to experience that again," she explains.
After leading a major industrial project, she has now moved back toward a more technical role, dividing her time between her position as a research engineer and her expertise in industrial business development.
Toward more directional light
While LEDs themselves are no longer a new research topic, their miniaturization into light sources for display applications remains an active area of research. Miniaturization, however, introduces effects that can degrade device performance.
The team is therefore working to understand and mitigate these effects, particularly for optical systems with low numerical apertures, or narrow light acceptance cones.
Funded by France 2030, the project aims to optimize the directionality of light sources so that they emit primarily within the desired cone.
"Poorly directed light means wasted energy," explains Julia Simon. "This is a key issue for the battery life of portable devices such as augmented reality glasses."
The award-winning publication provides an overview of the approaches developed in the laboratory to improve directionality, including sloped pixel etching, hemispherical micro-optics, and highly reflective distributed Bragg reflectors (DBRs).
The research also relies on a simulation methodology that makes it possible to explore different optical architectures within a matter of weeks, rather than the months or even years that would otherwise be required.
Proofs of concept have also been developed. They implement the approaches investigated - including Bragg mirrors and microlenses - and have been demonstrated at the scale of a 200 mm wafer, highlighting the manufacturing maturity and industrialization potential of the technology.
Applications beyond consumer displays
For Julia Simon, the award received in Japan is above all a recognition of a collective effort.
"Behind every publication on a component lies the contribution of dozens of colleagues, from design to characterization."
Beyond display applications, the team's expertise in light directionality is also relevant to an emerging field: chip-to-chip optical communication modules, which are being considered for high-performance computing centers and large-scale artificial intelligence models.
This is one of the reasons why the publication has already generated initial interest from industrial and academic partners during IDW. To be continued…