Master of Science Jon Richard Sommernes will Tuesday December 2nd, 2025, at 12:15 hold his Thesis Defense for the PhD degree in Science. The title of the thesis is:
« Advancing Oblique Plane Microscopy for High-Resolution Imaging in Aquatic Organisms »
Oblique Plane Microscopy (OPM) enables high-speed, optically sectioned volumetric imaging, yet faces inherent trade-offs between resolution, field of view, and speed. This thesis characterizes these limitations and advances OPM through theoretical optimization and system design, with a focus on marine biology applications. Using vectorial diffraction simulations and Debye-based point spread function analysis, we quantified how illumination angle, polarization, signal strength, and tertiary immersion index affect performance. We show that for samples with high fluorescence anisotropy, s‑polarized light-sheets yield higher average resolution and improved light efficiency across configurations. To address the constraints of low‑magnification OPM, we introduce axial sweeping in a non‑orthogonal dual‑objective design, achieving near‑isotropic, sub‑cellular resolution over millimeter‑scale fields of view. Applied to Nematostella vectensis, our mesoscopic axially swept OPM captures 1 × 0.7 × 0.4 mm volumes at 1.7 × 2.6 × 3.7 μm resolution and 0.5 Hz, enabling detailed observation of morphology–behavior coupling. Building on this foundation, we developed a multimodal imaging system that integrates OPM with a projection OPM (pOPM) and a multifocus microscope (MFM). pOPM provides single‑exposure, optically sectioned projections with dynamic angle selection, facilitating rapid, low‑dose visualization and 3D localization in sparse scenes. MFM records multiple focal planes simultaneously for high‑throughput volumetric sampling. We demonstrate the utility of this platform for live imaging of salmon skin keratocyte cells (SKCs), whose fast, dynamic behavior challenge conventional systems. The low phototoxicity and high spatiotemporal resolution of our instruments enabled quantitative tracking of SKC–bacteria interactions. Together, these results advance the state of the art in OPM, provide practical routes to overcoming its limitations, and expand its applicability to demanding biological problems, particularly in marine systems.
1st Opponent: Professor Clemens Kaminski, Department of Chemical Engineering and Biotechnology, University of Cambridge
2nd Opponent: Professor Olof Mikael Lindgren, Department of Physics, Norwegian University of Science and Technology, Trondheim
Internal member and leader of the committee: Professor Jana Jágerská, Department of Physics and Technology, UiT
The defence and trial lecture will be streamed from these following links at Panopto:
Defence (12:15 - 15:00)
Trial Lecture (10:15 - 11:15)
The thesis is available Here