Simo Pajovic
Department of Mechanical Engineering, Massachusetts Institute of Technology
Controlling Light-Matter Interactions in Novel Emitters:
Thermal Radiation, Scintillation, and Beyond
Abstract – In mechanical engineering, thermal radiation is the best-known example of light-matter interactions, but non-thermal radiation is prevalent in a wide variety of applications, including medical imaging, manufacturing, and sensing. Scintillation—the emission of light when a high-energy particle passes through a material—is of particular interest because of its high efficiency, access to a wide spectral range, and use in imaging and detection. This process can be modeled using fluctuational electrodynamics similarly to thermal radiation, meaning they are analogous. In this talk, I will describe my efforts during my PhD to advance both our fundamental understanding of and critical applications based on control of thermal radiation and scintillation. I will describe how we experimentally observed nonreciprocal reflection of mid-IR light in highly doped InAs at low magnetic fields (< 0.2 T) using both spectroscopic ellipsometry and FTIR. Our work demonstrates that nonreciprocity can be observed at low magnetic fields without coupling to resonant modes, i.e., using a flat surface rather than a patterned surface designed to resonantly interact with light [1]. This advances our fundamental understanding of mid-IR nonreciprocity and has implications for sensing and efficiency of systems such as PV cells. Then, I will shift gears to X-ray imaging, where my focus has been on source-to-detector improvements using nanophotonics. First, I will describe a strategy for increasing the operating power of X-ray tubes using “nanophotonic thermal management.” We theoretically predicted that nanophotonically patterning the anode of an X-ray tube can lead to a 1.25× enhancement in operating power (a proxy for X-ray generation) by enhancing radiative heat transfer between the anode and its surroundings. Second, I will discuss steps we have taken toward improving the scalability of so-called “nanophotonic scintillators” for X-ray imaging. Using a nanophotonic scintillator with a lateral area of 4 cm × 4 cm, we imaged a biologically relevant sample for the first time, paving the way for clinical applications of nanophotonic scintillators [2].
[1] S. Pajovic, Y. Tsurimaki, X. Qian, G. Chen, and S. Boriskina, arXiv:2410.06596 (2024). In production at Optics Express.
[2] L. Martin-Monier, S. Pajovic, M. Abebe, J. Chen, S. Vaidya, S. Min, S. Choi, S. Kooi, B. Maes, J. Hu, M. Soljačić, and C. Roques-Carmes, arXiv:2410.07141 (2024). Under review at Nature Communications.
Bio – Simo Pajovic (see-moh pie-oh-vitch) is a MathWorks Engineering Fellow and PhD Candidate co-advised by Dr. Svetlana Boriskina (MechE) and Prof. Marin Soljačić (Physics). Previously, he was an MIT Presidential Fellow, an NSF Graduate Research Fellow, and a DOE SCGSR Fellow (hosted by Los Alamos National Laboratory). As both a theorist and experimentalist, Simo’s research lies at the nexus of light-matter interactions and critically important applications such as energy and medicine. Research topics he has worked on include electromagnetic nonreciprocity, thermal radiation, spatiotemporally modulated metasurfaces, nanophotonic scintillators, and free-electron radiation.
This is an in-person seminar. If you opt to join via zoom use meeting ID 847 8406 9615 Passcode 051258