A theoretical study of the optical Stark effect in InGaAs/InAlAs quantum dots

Abstract

In this paper, we examine the three-level optical Stark effect of excitons in InGaAs/InAlAs quantum dots using renormalized wavefunction formulation. The system was assumed to be irradiated by two lasers in which a strong laser dynamically couples electron-quantized levels, while a weaker laser probes interband absorption. Our results show that, in the presence of the resonant strong laser, two new absorption peaks of excitons appear in the absorption spectrum as a clear indication of the effect. In addition, we propose that the formation of the effect in lowdimensional structures could have connection to the splitting of electron levels. Furthermore, we seek to explain the essential dependence of the amplitude and position of two peaks on pump field detuning.

On the Optical Stark Effect of Excitons in InGaAs Prolate Ellipsoidal Quantum Dots

“…This reduction is the consequence of the conservation of the electronic transition rate as discussed in Ref. [11]. In short, the above results demonstrate the existence of the threelevel optical Stark effect of exciton in the prolate ellipsoidal quantum dots.…”

“…Quantum dot structures have many interesting applications, such as producing artificial atoms and molecules [5], single-electron transistors [6], and quantum dot lasers [7]. In recent years, there has seen many studies on optical properties in quantum dots with different shapes, for example, cylindrical, cubic, and spherical quantum dots [8][9][10][11][12]. These studies show that optical properties of quantum dots are highly dependent on external fields and size of quantum dots.…”

“…In general, optical Stark effect has potential applications in manufacturing ultrafast optical switching of future optical devices [11,18], optical modulators [19], mesoporous hybrid multifunctional system [20], and optically controlled field-effect transistors [21]. The optical Stark effect of excitons in quantum dots has also been of interest in both experimental and theoretical research [11,[22][23][24] but mainly for spherical quantum dots. The investigation of this effect in a more complicated and more practical shaped quantum dot structures, such as ellipsoidal quantum dots, has not been carried out in detail.…”

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

“…As a result, we see that the absorption spectra of the excitons shift to a lower energy region as the wire radius becomes larger. It is worth mentioning that we have applied our theory for the other low-dimensional structures such as quantum dots and quantum wells and we have obtained the similar results [55,56]. Journal of Nanomaterials…”

“…We also found that, in Figure 2, the intensity of the exciton absorption spectra in the case of without pump wave (dashed line) appears much higher than that in the presence of the pump wave (solid line). This reduction is due to the act of the conservation of the transition rate [55]. We realize that, by turning the pump laser on or off, this effect can control the system to work as an optical switching by letting the probe laser beam of certain frequency propagate through it or not.…”