Exact formulation of the mutual particle-cavity dynamics and its use for the study of loss threshold phenomenon under magnetization
Abstract – Light-matter interaction plays a pivotal role in pushing forward nanotechnology. A particularly important setup involves a resonating particle, say an emitting molecule or a macroscopic quasi-statically resonating plasmonic or ferromagnetic sphere, that is located inside a cavity.
In this work, we provide an analytic formulation for the exact calculation of the mutual dynamics between a resonant particle and a rectangular cavity in which it is located. The particle is assumed to be small on the wavelength, and thus, its excitation is dominated by a dipolar response that can be described using the discrete dipole approximation and polarizability theory. The dipolar response depends on the particle’s polarizability function which encapsulates the particle’s materials and geometry, and on the local field acting on the particle. In principle, the latter is nothing more than the backscattering of the particle field by the cavity walls. However, its derivation may be challenging since it involves a three-dimensional singularity subtraction of the Green’s function in the cavity and the Green’s function in the free space that are differently represented. In this work, we discuss the use of a recursive ladder-type process involving alternative Green’s function representations to calculate the local field in a computationally efficient and numerically stable manner. Using this approach, we solve exactly several strongly coupled particle-cavity systems and calculate the collective resonance frequencies of the system.
As a particularly interesting example, we focus on the case when the plasmonic particle is subject to a static magnetic field, . In this case, its gyrotropic response gives rise to non-reciprocal dynamics of the ambient surroundings. This dynamics depends on the particle’s excitation, which in turn depends on the gyrotropic material damping rate . Thus, intuitively speaking, the heavier the gyrotropic material loss is, the weaker the non-reciprocal response will be. This is indeed the case when the particle is located in free space. However, when the gyrotropic particle is placed inside a cavity, we show that the non-reciprocity measure is robust against material loss up to a specific loss threshold, that depends on the magnetic biasing .
Bio – Dr. Yakir Hadad received the B.Sc. and M.Sc. degrees (summa cum laude) in electrical and computer engineering from the Ben Gurion University of the Negev, Be’er Sheva, Israel, in 2006 and 2008, respectively, and the Ph.D. degree in physical electronics from Tel Aviv University, Tel Aviv, Israel, in 2014.,From 2015 to 2017, he was a Post-Doctoral Fellow with the Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX, USA. During recent years, he also spent several periods as a Visiting Scientist with the FOM Institute Atomic and Molecular Physics (AMOLF), Amsterdam, The Netherlands, in Fall 2015, and the University of Pennsylvania, Philadelphia, PA, USA, in Spring 2013 and in Summer 2018. In 2017, he joined the Department of Physical Electronics, Faculty of Engineering, Tel Aviv University, where he is currently an Associate Professor. His research interest spreads on a wide range of wave modeling problems as well as on analytical and semi-analytical methods in electromagnetics and acoustics, with a particular emphasize on wave phenomena in complex media with applications in overcoming bounds of wave theory, Dr. Hadad received the Felsen Award for Excellence in Electrodynamics from the European Association for Antennas and Propagation in 2016, the 2017 recipient of the prestigious Alon Fellowship for Outstanding Young Faculty from the Israeli Council of Higher Education, Listed in Tel-Aviv University Rector’s list for excellence in teaching, and won the 2020 Krill Prize for excellence in research by the Wolf Foundation.
This is an in-person seminar. If you opt to join via zoom use meeting ID 837 9843 9863 Passcode 700331