Colloquium with Dr. Mazi Jalaal (UVA) and Dennis van de Lockand (VU Amsterdam)
12:30 - 12:50 Dennis van de Lockand, PhD candidate, Biophotonics & Medical Imaging, VU Amsterdam
Title: Femto- to picosecond time-resolved infrared photothermal imaging.
Abstract: The talk will focus on a developed pump-probe scheme where samples are excited via femtosecond near and mid-infrared pulses of various frequencies after which their response is imaged in time (up to tens of nanoseconds) using widefield off-axis holography. These experiments give us more insight on the vibrational dynamics that happen instantly after excitation and couples this to the thermal dynamics that occur after. From these dynamics we can then determine certain parameters like molecular composition and sample stiffness. So a little bit of fundamental science and a little bit of practical application.
12:50 -13:45 Dr. Mazi Jalaal, Associate Professor at Van der Waals-Zeeman Institute (Institute of Physics), Universiteit van Amsterdam
Title: Light and Mechanics in Living Matter
Abstract: Light sustains life, but it can also damage it; forcing living systems to sense, process, and respond to light across multiple timescales. In this talk, I will show how chloroplasts, the photosynthetic organelles of plants and algae, form dense, interacting assemblies whose collective behavior is governed by physical principles rather than purely biochemical control. Combining experiments and theory, we reveal chloroplasts as active matter in confinement, exhibiting glassy dynamics, mechanical interactions, and memory effects. In bioluminescent dinoflagellates, chloroplasts organize into a reticulated network that behaves as a biological metamaterial, enabling large, reversible deformations under strong confinement and rapid adaptation to changing light conditions. These results position living cells as programmable physical systems and raise questions that cut across disciplines: from biology and soft-matter physics to photonics, physical chemistry, and emerging concepts of memory and learning in living matter.