arXiv subjects

Samit Kumar Hazra

Publications and source records attributed to Samit Kumar Hazra.

4 recordsLinked to original sources

arXiv2024

Arbitrary vector beam generation in semiconductor quantum dots

We have proposed an arbitrary vector beam (VB) generation scheme in a thin disk-shaped quantum dot (QD) medium considering phonon interaction. The QD biexciton system exhibits interplay between first and third-order nonlinear susceptibility between two orthogonal circular polarisation transitions. Three QD transitions are coupled with one applied weak and two strong control orbital angular momentum (OAM) carrying fields. Therefore, the applied field experiences absorption, and a new field with the desired OAM is generated via four-wave mixing (FWM). These two orthogonal field superpositions produce VB at the QD medium end. We have also demonstrated the polarization rotation of a VB by changing only the relative control field phase. Additionally, we have analyzed the effect of temperature on the VB generation.

quant-ph↗

arXiv2023

Nondegenerate two-photon lasing in a single quantum dot

We propose two-mode two-photon microlaser using a single semiconductor quantum dot grown inside a two-mode microcavity. We explore both incoherent and coherent pumping at low temperatures to achieve suitable conditions for two-mode two-photon lasing. The two-mode two-photon stimulated emission is strongly suppressed but the single-photon stimulated emission is enhanced by exciton-phonon interactions. In coherently pumped quantum dot one can achieve large two-mode two-photon lasing where single-photon lasing is almost absent. We also discuss generation of steady state two-mode entangled state using two-photon resonant pumping.

quant-ph↗

arXiv2023

Structured beam controlled super-resolution in quantum dots via rapid adiabatic passage

We theoretically investigate rapid adiabatic passage (RAP) based super-resolution microscopy in a two-level quantum dot (QD) system. The system consists of a QD interacting with two structured beams, accompanied by chirping and a time delay. The central concept of this work is inspired by the stimulated emission depletion (STED) microscopy technique. To understand the physical mechanism behind super-resolved spot formation, we employ a variational master equation for the density matrix, incorporating both radiative and non-radiative decay processes. A suitably chosen spatiotemporal envelope of the structured beams enables the formation of a super-resolved image. Unwanted low-intensity circular rings around the focal spot are suppressed using Bessel-modulated truncated structured Laguerre-Gaussian (LG) and super-Gaussian (SG) beams. We also study the temperature dependence of the imaging scheme. The numerical results confirm that at low pulse areas, exciton-phonon coupling distorts the image, whereas at higher pulse areas, exciton-phonon decoupling preserves the image resolution. Hence, the proposed scheme may open up new possibilities for nanoscale imaging and bioimaging applications using QDs.

cond-mat.mes-hall↗

arXiv2023

Self-induced Transparency in a Semiconductor Quantum Dot medium at ultra-cold temperatures

We investigate the feasibility of minimum absorption and minimum broadening of pulse propagation in an inhomogeneously broadened semiconductor quantum dot medium. The phonon interaction is inevitable in studying any semiconductor quantum dot system. We have used the polaron transformation technique to deal with quantum dot phonon interaction in solving system dynamics. We demonstrate that a short pulse can propagate inside the medium with minimal absorption and broadening in pulse shape. The stable pulse area becomes slightly higher than the prediction of the pulse area theorem and is also dependent on the environment temperature. The change in the final pulse shape is explained very well by numerically solving the propagation equation supported by the susceptibility of the medium. Our system also exhibits the pulse breakup phenomena for higher input pulse areas. Therefore, the considered scheme can have important applications in quantum communication, quantum information, and mode-locking with the advantage of scalability and controllability.

quant-ph↗