Influence of the asymmetric excited state decay on coherent population trapping

Abstract

Electromagnetically induced transparency (EIT) is an optical phenomenon which allows a drastic modification of the optical properties of an atomic system by applying a control field. It has been largely studied in the last decades and nowadays we can find a huge number of experimental and theoretical related studies. Recently a similar phenomenon was also shown in quantum dot molecules (QDM), where the control field is replaced by the tunneling rate between quantum dots. Our results show that in the EIT regime, the optical properties of QDM and the atomic system are identical. However, here we show that in the strong probe field regime, i.e., “coherent population trapping” (CPT) regime, it appears a strong discrepancy on the optical properties of both systems. We show that the origin of such difference relies on the different decay rates of the excited state of the two systems, implying in a strong difference on their higher order nonlinear susceptibilities. Finally, we investigate the optical response of atom/QDM strongly coupled to a cavity mode. In particular, the QDM-cavity system has the advantage of allowing a better narrowing of the width of the dark state resonance in the CPT regime when compared with atom-cavity system.

Optimal and robust control of population transfer in asymmetric quantum-dot molecules

“…[35][36][37][38][39][40][41][42][43] We concentrate on achieving optimal and robust population transfer in an asymmetric double quantum-dot molecule (ADQDM). [44][45][46][47][48] The present system consists of two SQDs with distinct band structures connected through tunneling. Extensive research has been conducted on such systems, revealing intriguing optical phenomena such as tunneling-induced transparency, [49][50][51] tunneling-induced optical limiting, [52] tunneling-induced Talbot effect, [53] and tunneling-induced phase grating.…”

Multiple transparency windows and Fano interferences induced by dipole-dipole couplings

“…[8], the fundamental idea of the EIT has been extended to other systems. Nowadays we one can observe the interference between different absorption pathways, resulting in adjustable trans- * halyneborges@df.ufscar.br parency windows, in a large variety of different physical systems as coupled classical [18] or quantum harmonic oscillators [19], two-coupled optical cavity modes [20,21], two-level atom coupled to a cavity mode [22,23], quantum dot molecule [24][25][26], plasmonic systems [27,28], optomechanical oscilators [29,30], metamaterials [31,32], etc. By applying more control fields, coupling the excited state to additional ground states, more transparency windows can be obtained, thus appearing double-EIT phenomenon, for instance, in a four-level tripod atomic system [33].…”