There is an aspect of Electromagnetics that has been somewhat overlooked. Common everyday objects can act as electromagnetic resonators. Indeed ordinary objects have a series of resonant frequencies extending from radio waves up to optical frequencies. These resonant modes can be modeled as LC circuits. Thus every object that we encounter is an LC resonator. Since LC circuits support ac currents, and since ac currents imply electron acceleration, they inherently radiate into the far-field. Therefore ordinary objects that we come across, in our daily lives, can act as electromagnetic antennas. This means that ordinary object have a Q-factor and a radiation Q-factor for each resonant mode. The lowest frequency resonance is the most characteristic of the object geometry, but there is an entire spectrum of higher frequencies to work with, different and characteristic for every object. Many of the properties that have been attributed to plasmonic resonances are actually universal, and they arise already in ordinary electromagnetics. In communications technology, the antenna application is the most important. The antennas in cellphones, carried by almost everyone on the planet, are examples of multi-frequency resonant objects, enabling wireless connectivity.
|Où?||PER 08 Zoom Meeting
Chemin du Musée 3
|Intervenants||Prof. Eli Yablonovitch, UC Berkley
|Contact||Département de Physique
Prof. Frank Scheffold