A study on quantum beats of excitons in GaAs/AlGaAs circular cylindrical quantum wires

Abstract

This paper presents a theoretical investigation of quantum beats of excitons in GaAs/AlGaAs circular cylindrical quantum wires. A three-level model of excitons, including a ground state and two excited states, has been applied to derive the renormalized wavefunctions and the time-dependent absorption intensity of excitons when the system is irradiated by a strong pump laser resonating with the distance between the two excited-levels. Our results show that a periodic oscillation form of the absorption intensity, obvious evidence of the quantum beat behavior, has appeared. Furthermore, the mechanism of the generation, as well as the effects of the wire radius and the pump laser detuning on the frequency (period) and amplitude of quantum beats, have been explained in detail. These results suggest potential applications in the fabrication of some quantum computation devices.

Three-Level Optical Stark Effect of Excitons in GaAs Cylindrical Quantum Wires

“…where r is the length from the wire axis to the considered position. The envelope wave functions describing the states of the electron and hole in the confined plane can be written as [48,49] Ψ e,h mn r…”

“…In this study, we investigate the three-level excitonic optical Stark effect in GaAs cylindrical quantum wires utilizing the renormalized wave function formulation. We have also successfully applied that formulation to study the excitonic quantum beats [48], a phenomenon that occurs as the consequence of the three-level excitonic optical Stark effect in the same structures of quantum wires. Therefore, both the recent report and Ref.…”

“…Therefore, both the recent report and Ref. [48] share the same starting point. Hence, we can expect to successfully study the three-level excitonic optical Stark effect in those structures.…”

“…Journal of Nanomaterials in which Π j ð r ! Þðj = 0, 1, 2Þ are the stationary wave functions of the particles in the quantum wire and are defined by[48] …”

Quantum Beat of Excitons in the Prolate Ellipsoidal Quantum Dots

“…Using ultrashort laser pulses with various experiments [24][25][26][27][28][29][30], scientists have observed quantum beats of excitons in different semiconductor structures. Theoretically, scientists have applied many methods to study the quantum beats of excitons in quantum structures [25,[31][32][33][34][35][36], of which the most convenient is the renormalized wavefunction method [32,35,36].…”