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

TL;DR

This paper theoretically investigates the nonlinear optical behavior of a 2D quantum-dot supercrystal, revealing multistability, self-oscillations, chaos, and potential for innovative all-optical device applications.

Contribution

It introduces a novel method for analyzing the nonlinear steady-state and bifurcation dynamics of quantum-dot supercrystals, highlighting their complex optical phenomena.

Findings

Supercrystal exhibits multistability and self-oscillations.

Chaotic behavior emerges under certain conditions.

Potential for designing all-optical switches and THz pulse generators.

Abstract

We conduct a theoretical study of the nonlinear optical response of a two-dimensional semi-conductor quantum dot supercrystal subjected to a quasi-resonant continuous wave excitation. Aconstituent quantum dot is odeled as a three-level ladder-like system (comprising the ground, theone-exciton, and the bi-exction states). To study the stationary response of the supercrystal, wepropose an exact linear parametric method of solving the nonlinear steady-state problem, whileto address the supercrystal optical dynamics qualitatively, we put forward a novel method to cal-culate the bifurcation diagram of the system. Analyzing the dynamics, we demonstrate that thesupercrystal can exhibit multistability, periodic and aperiodic self-oscillations, and chaotic behavior,depending on parameters of the supercrystal and excitation conditions. The effects originate fromthe interplay of the intrinsic nonlinearity of quantum dots and the retarded inter-dot dipole-dipoleinteraction. The latter provides a positive feedback which results in the exotic supercrystal opticaldynamics. These peculiarities of the supercrystal optical response open up a possibility for all-opticalapplications and devices. In particular, an all-optical switch, a tunable generator of THz pulses (inself-oscillating regime), a noise generator (in chaotic regime), and a tunable bistable mirror can bedesigned.