Site-Selective, Intrinsically Bistable Luminescence ofYb3+Ion Pairs inCsCdBr3

Abstract
We report the first observation of intrinsic optical bistability in CsCdBr3:1% Yb3+ and show, using site-selective spectroscopy, that only the asymmetric, strongly coupled Yb3+ ion-pair minority site gives rise to hysteresis of near-infrared and cooperative up-conversion luminescence as a function of incident laser intensity below 15 K.