Laser Physics Letters

Spatially varying optical characteristics in quantum-dot molecules through interdot tunneling

R O Saleh, M S Mohammed, Shavan K. Askar, Nashwan Salah Aldeen Darwish, Wesam Radhi Kadhum, Murtadha Lafta Shaghnab, A A Ibrahim, Abhishek Kumar, Ahmed Elawady, Aisha A. Omran

Published Feb 15, 2024• 0 citations

Publisher

Abstract

Abstract In this paper, we investigate the spatially dependent absorption characteristics in structurally asymmetric quantum-dot molecules (QDMs), characterized by four energy levels interacting with position-dependent beams and varying system parameters. We explore the effects of detuning, standing wave intensity, and the relative phase of applied fields on the absorption patterns within the medium. A diverse array of patterns emerges, including cross-like structures, ring-like formations, and localized absorption maxima, illustrating the intricate interplay between these parameters and the spatial distribution of absorption features. The introduction of a vortex-shaped control field adds a new dimension to the study, revealing azimuthal dependence and providing a novel perspective for manipulating absorption and gain properties based on the orbital angular momentum of the control field. This work contributes to a comprehensive understanding of the intricate dynamics governing spatially dependent absorption in QDMs, offering valuable insights for controlled manipulation and practical applications in quantum systems.

DOI: 10.1088/1612-202x/ad26ed

Related papers

Two-dimensional asymmetric diffraction grating in quantum dot molecules system controlled by vortex light

Jiaqian Li, Duo Zhang, Junbing Guo +1 more

Abstract We propose a theoretical scheme for realizing a two-dimensional (2D) asymmetric diffraction grating in a four-level quantum dot molecules (QDMs) system with double tunneling effects. The QDMs system interacts with a weak probe field, a 2D SW control field and a composite Laguerre–Gaussian (LG) vortex field. By adjusting system parameters such as the orbital angular momentum (OAM) number, the beam waist parameter of the vortex light, the tunneling strength, and the detuning of the standing-wave (SW) field, the energy distribution and the diffraction intensity of the probe field can be controlled effectively. In addition, the detuning of the probe field can be used to achieve the symmetrical switching control of the 2D diffraction grating between the second and the fourth quadrants. This investigation may have potential application in beam splitting technology and optical device design.

Physica ScriptaJun 9, 20252 citations

Asymmetric Fraunhofer diffraction in a quantum dot molecule via tunneling-induced transparency

Mostafa Taghizadeh, Forough Bozorgzadeh, G. H. Bordbar

We manipulate the coupling effect between interdot tunneling and the external control field to study the optical diffractive property in a quantum dot molecule (QDM) system. Based on the density matrix approach, an analytical relation is obtained for the optical susceptibility, which shows tunneling-induced transparency (TIT) in the absorption spectra. We propose an innovative optoelectronic device called tunneling-induced grating, which operates based on the diffraction of the forward-transmitted probe laser light. The diffraction integrals for the far-field regime (i.e., Fraunhofer diffraction) are numerically solved, and the effect of interdot tunneling coupling strength on the diffraction patterns is studied. It is shown that the transmission is increased under tunneling-induced quantum coherence. The weak probe light can be diffracted into higher-order directions upon applying a standing-wave control field. The optimal parametric condition for maximum first- and second-order diffractions is obtained. The results find the potential applications in quantum information processing devices, such as all-optical grating and switches at low light levels.

Physical review. B./Physical review. BApr 28, 20233 citations

Voltage-controlled two-dimensional Fresnel diffraction pattern in quantum dot molecules

Hamed Mehrabzadeh, Hamid Khoshdel, Mohammad Mahmoudi +2 more

This study explores the influence of inter-dot tunneling effects within a quantum dot molecule on the Fresnel diffraction phenomenon. Our findings indicate that the Fresnel diffraction of the output probe Gaussian field can be manipulated by adjusting the inter-dot tunneling parameter's strength and the characteristics of the coupling field. The inter-dot tunneling effect establishes a closed-loop system, setting conditions for the interference of the applied fields. We specifically examine a Laguerre-Gaussian (LG) coupling field, investigating how its properties-such as strength, value, and sign of the orbital angular momentum (OAM)-impact the Fresnel diffraction of the output probe field. Increasing the inter-dot tunneling parameter and the coupling LG field's strength allows for control over the spatial distribution of the Fresnel diffraction pattern. Notably, the inter-dot tunneling parameter can disturb the symmetry of the diffraction patterns. Additionally, considering a negative OAM for the coupling LG field transforms the diffraction pattern into its inverse shape. This suggests that, in the presence of the inter-dot tunneling effect, the Fresnel diffraction pattern is contingent on the direction of rotation of the helical phase front of the coupling LG field. Our results offer insights into quantum control of Fresnel diffraction patterns and the identification of OAM in LG beams, presenting potential applications in quantum technologies.

Scientific ReportsMar 9, 20240 citations

Two-dimensional asymmetric diffraction induced by vortex light in quantum-dot-molecule systems under spontaneously generated coherence

Yiming Xu, Yiming Zhang, Shenwei Li +3 more

Quantum dot molecules (QDMs), with their unique optoelectronic properties derived from quantum confinement and tunneling effects, are not only promising for advanced photonic applications but also provide the intrinsic advantage of nanoscale dimensions, which is critical for integrated miniaturized devices. In this work, we propose a scheme to realize a high-intensity two-dimensional asymmetric electromagnetically induced diffraction grating in a QDMs system by incorporating spontaneously generated coherence (SGC) and dual tunneling channels. Our theoretical analysis shows that the presence of SGC markedly enhances the intensity and efficiency of higher-order diffractions. Furthermore, by adjusting the orbital angular momentum and beam waist of vortex beams, we not only amplify the disparity in asymmetric diffraction and enhance the efficiency of the third-order diffraction peak, but also enable a lossless spatial interchange between the diffraction peak positions and those at symmetric positions solely by reversing the orbital angular momentum direction. Additionally, tuning the interdot tunneling strength increases the maximum third-order diffraction intensity by three orders of magnitude, reaching an intensity that is more than ten times higher than the third-order diffraction intensity observed at symmetric positions. These results, which fully leverage the nanoscale advantage and tunable characteristics of QDMs, offer a solid foundation for the implementation of compact photonic devices and pave the way for potential applications in optical diffractive neural networks and electromagnetically induced quantum holography.

Physical Review ANov 6, 20251 citation

Spatially structured transparency and transfer of optical vortices via four-wave mixing in a quantum-dot nanostructure

Rahmatullah Rahmatullah, Muqaddar Abbas, Ziauddin Ziauddin +1 more

We propose a scheme to generate structured light using a medium consisting of semiconductor quantum dots via four-wave mixing (FWM). We consider a four-level quantum-dot structure where two strong electromagnetic fields couple upper-level biexciton transitions, whereas a weak field is applied to one of the ground-level exciton transitions. A weak signal field is generated, corresponding to a second ground-level exciton transition; thus the overall configuration transforms into a closed-loop diamond-type shape. To realize a spatially dependent modulating quantum-dot medium, we consider strong coupling fields as structured lights and investigate different regions of spatially structured electromagnetically induced transparency via absorption of the generated signal field. The azimuthal phase-dependent modulation of the absorption profile of the generated signal field is the key factor behind the creation of structured light. In addition, we also demonstrate transfer of orbital angular momentum (OAM) of the control beam to the generated beam through the FWM process and study the effect of phase mismatch on efficiency of the OAM transfer.

Physical Review AFeb 14, 202073 citations

Azimuthal modulation of electromagnetically-induced transparency by using asymmetrical Laguerre-Gaussian beams

Seyedeh Hamideh Kazemi, Mohammad Mahmoudi

Recently, the generation and detection of structured light field have drawn a great deal of attention, due to their importance in high-capacity optical data storage and quantum technology. In this letter, we explore the azimuthal modulation of optical transparency in a four-level double-V type quantum system near a plasmonic nanostructure. A Laguerre-Gaussian beam and the interaction of the system with free-space vacuum modes have been employed to create the phase-dependent absorption of a non-vortex probe field. First, we demonstrate how to identify the azimuthal index associated with the conventional LG beam via measuring the probe absorption so that the phase information of such a beam gets encoded on the spatially-dependent absorption profile with angularly-distributed lobes. Also, a spatially-varying optical transparency can be formed, due to the periodic variation of the absorption spectrum. Then, asymmetrical Laguerre-Gaussian beams are used to extend the selective spatial transparency mechanism to asymmetric spatially-structured windows, allowing for optical manipulation of spatial modes at arbitrary positions. Moreover, we investigate the influence of the asymmetric parameter on the features of the spatial inhomogeneities and show how the beams enable us to imprint the phase information of the orbital angular momentum at a desired position.

arXiv:2002.09697Feb 22, 20200 citations