In the burgeoning field of light-matter interactions, angular momentum has emerged as a pivotal factor, driving innovative research directions. This study delves into the interaction dynamics between vortex lights and an electromagnetically induced transparency (EIT) medium, with a primary focus on elucidating the underlying mechanism of angular momentum transfer. Through comprehensive theoretical analysis and numerical simulations, it is demonstrated that when the probe field carries orbital angular momentum (OAM), the dispersion and absorption characteristics of the EIT medium undergo periodic modulation. This modulation is intricately determined by the azimuthal phase and topological charge of the beam. Notably, the OAM in the driving field exerts no such influence on the medium's properties. Leveraging vortex phase plates (VPPs) or spatial light modulators (SLMs) to manipulate the tunable OAM enables dynamic control over the EIT effect. This breakthrough not only deepens our understanding of light-matter interactions at the quantum level but also unlocks new avenues for high-dimensional quantum information processing and advanced optical communication technologies.
In the burgeoning field of light-matter interactions, angular momentum has emerged as a pivotal factor, driving innovative research directions. This study delves into the interaction dynamics between vortex lights and an electromagnetically induced transparency (EIT) medium, with a primary focus on elucidating the underlying mechanism of angular momentum transfer. Through comprehensive theoretical analysis and numerical simulations, it is demonstrated that when the probe field carries orbital angular momentum (OAM), the dispersion and absorption characteristics of the EIT medium undergo periodic modulation. This modulation is intricately determined by the azimuthal phase and topological charge of the beam. Notably, the OAM in the driving field exerts no such influence on the medium's properties. Leveraging vortex phase plates (VPPs) or spatial light modulators (SLMs) to manipulate the tunable OAM enables dynamic control over the EIT effect. This breakthrough not only deepens our understanding of light-matter interactions at the quantum level but also unlocks new avenues for high-dimensional quantum information processing and advanced optical communication technologies.
Electromagnetically induced transparency (EIT) is a fundamental effect in quantum optics, providing a versatile platform for quantum technologies. A growing frontier is the integration of EIT with structured light, particularly vortex beams. Extending this to the spatiotemporal domain, we herein study the propagation and evolution of spatiotemporal optical vortex (STOV) beams in an EIT medium. We derive an analytical solution for the evolved STOV field and its stability criterion, and analyze the propagation dynamics with a primary focus on the evolution of the phase singularity. Following the splitting of the initial multi-charge STOV phase singularity upon propagation, the dynamics of the resultant first-order phase singularities are governed by the interplay of first-order loss dispersion (FLD), second-order loss dispersion (SLD), and group velocity dispersion (GVD) of the EIT medium. FLD dictates their overall directional shift, while SLD governs their mutual separation. Under normal GVD, the phase singularities evolve into parallel π -phase step lines and subsequently undergo a topological charge reversal; under zero GVD, only π -phase step lines are formed without topological charge reversal; both transitions are absent under anomalous GVD. These transitions occur in the far zone when the STOV’s center frequency lies within the EIT window, whereas around the absorption peak, they occur at a distance just prior to the critical point beyond which the field collapses. Furthermore, we establish the condition under which the splitting of the initial multi-charge STOV phase singularity is entirely suppressed throughout propagation. STOVs carry intrinsic transverse orbital angular momentum (OAM), providing a new, orthogonal dimension for photonic encoding beyond the conventional longitudinal OAM of spatial optical vortices. Integrating STOVs with EIT merges this robust quantum resource with a platform for coherent dispersion engineering, enabling high-dimensional quantum information processing in a vastly expanded state space that combines both longitudinal and transverse OAM.
Abstract The theoretical investigation into spatially coherent control over electromagnetically induced transparency is carried out within a hybrid cavity system comprising a three-level atomic configuration, a mechanical resonator, and an optical cavity. The interaction involves driving a composite vortex light (CVL) with a three-level medium. Our findings reveal that the input-output cavity field can be systematically adjusted, resulting in changes to the transmission spectrum of the weak probe light. The transmission spectrum of the output light can be spatially controlled by manipulating the orbital angular momentum of the CVL and through parametric modulation of the system. Our simulations present a flexible approach for managing light-matter interactions in a hybrid optomechanical system.
We experimentally investigate the transfer of orbital angular momentum (OAM) of light in a solid driven by electromagnetically induced transparency (EIT). Under the condition of dynamical EIT, the OAM of the probe pulse is stored and retrieved in the experimental medium. By using a four-level double-lambda system to control the retrieval process of EIT storage, we show that OAM can be transferred from the probe field or the second control field to the newly generated signal field, which has a new spatial-frequency mode compared with the input mode. Furthermore, we use EIT-based four-wave mixing to investigate the direct OAM transfer without experiencing the storage, where we do not need to switch off and back on the control field.
Recently a scheme has been proposed for detection of the structured light by measuring the transmission of a vortex beam through a cloud of cold rubidium atoms with energy levels of the Λ-type configuration [N. Radwell et al., Phys. Rev. Lett.114, 123603 (2015) ]. This enables observation of regions of spatially dependent electromagnetically induced transparency (EIT). Here we suggest another scenario for detection of the structured light by measuring the absorption profile of a weak nonvortex probe beam in a highly resonant five-level combined tripod and Λ (CTL) atom-light coupling setup. We demonstrate that due to the closed-loop structure of CTL scheme, the absorption of the probe beam depends on the azimuthal angle and orbital angular momentum (OAM) of the control vortex beams. This feature is missing in simple Λ or tripod schemes, as there is no loop in such atom-light couplings. One can identify different regions of spatially structured transparency through measuring the absorption of probe field under different configurations of structured control light.
We propose a scheme to exchange optical vortices beyond electromagnetically induced transparency (EIT) but based on four-wave mixing (FWM) in a five-level atomic system consisting of two Λ subsystems linked via a weak driving field. When the laser fields are strong enough, the quantum interference responsible for the EIT in each Λ subsystem is washed out, giving rise to the Autler-Townes splitting (ATS). When only one of the control fields carries an optical vortex, it is shown that the generated FWM field obtains the vorticity of the vortex control. We distinguish between three different regimes, i.e., a pure EIT, a joint EIT-ATS, and a dual-ATS, where the optical angular momentum (OAM) translation can take place. Elaborating on the distinction between three regimes through numerical analysis, we find that the maximum energy conversion efficiency is obtained in the joint EIT-ATS and dual-ATS regimes. The latter is more favorable as the absorption losses vanish as the beam propagates into the atomic cloud. The results may find applications in the implementation of high-efficient frequency and OAM conversion devices for quantum information processing.
Vortex light, a unique optical field that carries orbital angular momentum (OAM), has attracted considerable attention in recent years. In this paper, we present a detailed theoretical analysis of OAM transfer from the input field to the generated signal field in a four-level double-Lambda system via the four-wave mixing (FWM) process, showing that their OAMs follow a specific algebraic relationship. We identify the optimal conditions for efficient vortex light transmission, analyze the influence of detuning on transmission efficiency and phase distortion, and specifically examine the scenario where the control field carries OAM the latter being essential for a complete characterization of OAM conservation in the FWM process, while all three aspects have been largely overlooked in the existing literature. Furthermore, we investigated the tunability of the group velocity between the probe and signal fields by modulating the Rabi frequencies of the two control fields and the relative phase between the probe and signal fields during the FWM process. We demonstrate that the conversion between matched vortex slow and fast light can be realized an effect that has not been widely explored in dual-Lambda-type systems. These results may hold promise for applications in quantum information storage and processing, quantum computing, and ultrasensitive detection.