Nonlinear optical response of a two-dimensional quantum dot supercrystal: Emerging multistability, periodic/aperiodic self-oscillations, and hyperchaos

TL;DR

This paper theoretically investigates the nonlinear optical behavior of a 2D quantum dot supercrystal, revealing multistability, self-oscillations, and chaos, with potential applications in nanoscale all-optical devices.

Contribution

It introduces an exact linear parametric method to analyze the nonlinear steady states and demonstrates complex dynamics arising from dipole interactions in quantum dot supercrystals.

Findings

System exhibits multistability, oscillations, and chaos depending on parameters.

Dipole-dipole interactions induce positive feedback leading to nonlinear dynamics.

Potential for nanoscale optical switches, THz pulse generators, and noise sources.

Abstract

We study theoretically the nonlinear optical response of a two-dimensional semiconductor quantum dot supercrystal under a resonant continuous wave excitation. A single quantum dot is modeled as a three-level ladder-like system with the ground, one-exciton, and bi-exction states. We propose an exact linear parametric method of solving the nonlinear steady-state problem. It is demonstrate that the system may exhibit multistability, periodic and aperiodic self-oscillations, and hyperchaotic behavior, depending on the system's parameters and frequency of excitation. The effects originate from the retarded dipole-dipole interaction of quantum dots. The latter provides a positive feedback which, in combination with the nonlinearity of SQDs, leads to an exotic nonlinear dynamics of the system indicated above. We discuss relevance of the underlined effects for nanosized all-optical devices. In particular, a quantum dot supercrystal may serve as a nanosized all-optical switch, a tunable generator of trains of THz pulses (in self-oscillating regime), as well as a noise generator (in chaotic regime) at the nanoscale. We show also that the supercrystal can operate as a bistable mirror. All this suggests various nanophotonic applications of such type of materials.