Collective emission of atoms in photonic bandgap materials

Abstract

The behaviour of two AI-Li dilute alloys having two different Li contents (1.7 and 3.7 at.%Li) has been studied using positron annihilation. The lifetime value is about 20 ps higher than that measured for pure AI and is independent of the Li content. When the specimens are cold rolled the lifetime increases to a value that is lower than the one currently associated with dislocations in A1 and does not depend on the Li concentration. After isochronal annealing the lifetime achieves the initial value t = 185 ps. The results are interpreted in terms of Li clustering.

Coherent dynamics of radiating atomic systems in pseudospin representation

“…Atoms can then start to radiate, even inside the prohibited band gap. This collective phenomenon for atoms with an atomic frequency inside the prohibited band gap is termed collective liberation of light [8,[64][65][66][67][68].…”

Superradiance by ferroelectrics in cavity resonators

“…This type of coherent emission, where the process starts with spontaneous atomic radiation, was first described by Dicke [12] and is often called Dicke superradiance [13]. The same mathematical description as for atomic superradiance is valid for exciton superradiance [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], including superradiance from quant um dots and wells [34][35][36][37][38][39][40] and for polariton superradiance [41][42][43][44][45][46].…”