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Hi, I'm YoonSeok Baek.

I'm currently at Sorbonne University, working in Hugo Defienne's team. I was recently awarded a 2026 ERC Starting Grant (FOSCADE) to develop computational methods that push fluorescence microscopy deeper into tissue. Before that, I was a postdoc with Sylvain Gigan at Laboratoire Kastler Brossel, and I received my Ph.D. in Physics from KAIST under the supervision of YongKeun Park.

My work sits at the intersection of optical physics, light microscopy, and computational imaging.

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Research Interests

I develop imaging methods that combine optical design, physical modeling, and computation. Rather than relying on any single tool, I look for ways to use them together, shaping how light is delivered and measured and pairing that with reconstruction methods, to extend what imaging can achieve beyond conventional settings.

Below are a few selected works that illustrate these directions.

Imaging and light control in scattering media

Scattering scrambles light, and with it the information light carries. This limits imaging in settings ranging from astronomy, where the culprit is atmospheric turbulence, to deep-tissue microscopy.

I developed methods for reconstructing 3D images of incoherent objects, such as fluorescent sources, hidden behind strongly scattering media, by retrieving optical field information that is normally inaccessible. I also introduced a technique for focusing light onto multiple hidden emitters at once, enabling controlled light delivery through scattering media.

Selected Papers:
1. Baek et al., Nature Photonics 17 (2023)
2. Baek et al., Nature Communications 16, 11653 (2025)

Phase imaging beyond conventional interferometry

Optical phase carries rich structural information about transparent samples, but measuring it accurately usually requires a complex interferometric setup or computationally intensive iterative reconstruction.

I developed Kramers–Kronig holographic imaging, a framework that retrieves phase images analytically and directly from intensity measurements, without a separate reference beam. The same principle also relieves the space–bandwidth bottleneck of conventional holographic microscopy, enabling phase imaging over a larger field of view or at higher spatial resolution.

Selected Papers:
1. Baek et al, Nature Photonics 14.2 (2020)
2. Baek et al, Optica 6.1 (2019)