Detuning Of Field Research Articles

One-Step Implementation of Collective Anti-Blockade in a Rydberg Ring

In contrast to Rydberg blockade, Rydberg anti-blockade allows multiple atoms to be simultaneously excited in the presence of significant nonlocal interactions and can lead to distinct phenomena and applications. This inspires us to examine here general conditions, numerical verifications, and realistic restrictions regarding the collective anti-blockade excitations of N Rydberg atoms equally arranged along a ring. We find that by adjusting the detuning of a pump field to compensate for nonlocal interactions between one atom and all others, it is viable to realize resonant excitations of N atoms but suppress far-detuned excitations of N−1 and fewer atoms under different conditions for an odd and an even number of atoms. Population dynamics of this Rydberg ring further show that one-step anti-blockade implementation can be attained at a cutoff time of the pump field, which increases quickly with the number of atoms. Hence, roughly perfect anti-blockade excitations are attainable only for a not-too-large N due to inevitable spontaneous Rydberg decay.

Coherent manipulation of intensity interrogation of sensitivity of the surface plasmon polariton waves at the dielectric and silver metal interface

AbstractIn this manuscript, Intensity interrogation of sensitivity of the surface plasmon polariton waves (SPPs) is coherently manipulated, at the interface of four‐level dielectric medium and silver metal using prism geometry. Sensitivity of SPPs with respect to refractive index is written as . A useful control in sensitivity is reported with probe and control fields detuning, Rabi frequency and decay rate. Sensitivity is a function of probe field detuning and control field Rabi frequency. The maximum sensitivity is reported to with probe field detuning and control field Rabi frequency, while minimum sensitivity is investigated to with control field phase and control field Rabi frequency. The sensitivity in this manuscript shows useful application in biosensor and photovoltaic devices.

Ultra-slow spin waves propagation based on skyrmion breathing

Spin wave has attracted significant attention in various fields because of its rich physics and potential applications in the development of spintronics devices in the post-Moore era. However, the analog of a subluminal-like propagation in the field of spin waves has not been well discussed. Here, we theoretically demonstrate the ultra-slow spin waves propagation in a nanoscale two-dimensional ferromagnetic film in the presence of magnon-skyrmion interaction. The minimum spin waves propagation velocity was estimated to be as low as 1.8 m s−1 by adjusting the system parameters properly, and the spin waves group delay and advance are dynamically tunable via the intensity or detuning of the control field, which allows the possibility of observing superluminal- and subluminal-like spin waves propagation in a single experimental setup. These results deepen our understanding of the spin wave–skyrmion interactions, open a novel and efficient pathway to realize ultra-slow spin waves propagation, and are expected to be applied to magnetic information storage and quantum operations of magnons.

Coherent control of the photonic spin Hall effect by Er3+ ion concentration in an Er3+-doped YAG crystal

We theoretically investigate the effect of doped Er3+ ion concentration on the spin Hall effect (SHE) of light reflected from a Kretschmann-Raether (K-R) structure. In such a structure, an Er3+-doped yttrium aluminum garnet (YAG) crystal acts as the substrate. The excitation of surface plasmon resonance(SPR) leads to the enhancement of the spin splitting of the reflected beam in the resonance reflection dip. Due to the variation of electric dipole moment and energy level lifetime induced by Er3+ ion concentration, the spin-dependent transverse shift is sensitively dependent upon Er3+ ion concentration. Furthermore, under different concentrations of Er3+ ion, the intensity and detuning of the control field have different effects on the magnitude, sign and position of the transverse shift. More importantly, the photonic SHE can be significantly enhanced via choosing the suitable values of the control intensity and detuning at 15% Er3+ ion concentration. Therefore, our scheme may provide a basis for selecting suitable Er3+ ion concentration to enhance the SHE of light in future integrated systems.

Conical diffraction in atomic vapor: Mathematical models and numerical calculations

This study investigated the conical diffraction characteristics in the honeycomb lattice of a Λ-type three-level energy system for rubidium atomic configuration. Its band structure incorporates Dirac cones in accordance with the plane wave expansion method. We determined that the rotation angle θ of the three vectors strongly impacted the cone diffraction profile. For θ=0° and 60°, in the reciprocal lattice space, the Dirac cone states were excited, and symmetric cone diffraction was supported. When 0<θ<60°, an asymmetric cone diffraction with a dark notch appeared on the outer edge of the conical ring. The results indicate that the frequency detuning of the coupling field and high-order nonlinear susceptibilities in the medium are effective and concise approaches to manipulate the occurrence of cone diffraction. The findings of this study enhance the understanding of the cone diffraction phenomena and broaden the practical applicability of atomic configuration.

Pump-Probe Optical Response and Four-Wave Mixing in a Zinc-Phthalocyanine-Metal Nanoparticle Hybrid System.

We investigate theoretically the optical response of a zinc-phthalocyanine molecular quantum system near a gold spherical nanoparticle with a radius of 80 nm. The quantum system is irradiated by a strong pump and a weak probe coherent electromagnetic field. Using the density matrix methodology, we obtain analytical expressions for the absorption, dispersion, and the four-wave-mixing coefficients. The influence of the nanoparticle on the spontaneous decay rate of the quantum system, as well as on the external fields, are obtained by an electromagnetic Green's tensor method. The spectroscopic parameters of the molecule are also obtained by ab initio methods. For the studied optical spectra, we find that, below a critical distance between the molecule and the plasmonic nanoparticle, determined by the minimal value of the effective Rabi frequency, single-peaked spectra are observed. Above this critical distance, the spectra exhibit the characteristic Mollow-shaped profiles. The enhancement of the pump field detuning induces the shift of the sideband resonances away from the origin. Lastly, and most importantly, regardless of the value of the detuning, the optical response of the system is maximized for an intermediate value of the interparticle distance.

Higher-Order Optomechanical Nonlinearity Based on the Mechanical Effect of Light

Nonlinear cavity optomechanics based on the mechanical effect of light has recently received considerable attention due to its potential applications in high-precision metrology. In this work, we theoretically studied the third-order optomechanical nonlinearity by using a perturbative approach, and an analytical solution is given, which can be extended to cases of higher-order optomechanical nonlinearity. Furthermore, the generation of a third-order sideband is analyzed in detail, and the results show that the amplitude of the third-order sideband shows a high dependence on the control field detuning, suggesting that the high-order nonlinear intensity can be enhanced by properly adjusting the detuning of the laser field rather than by a strong laser drive. In addition to providing insight into optomechanical nonlinearity, the analytical description of third-order optomechanical nonlinearity based on the mechanical effects of light may find applications in ultra-high precision measurement under low power conditions.

Manipulation of sensitivity of the surface plasmon polariton waves at the interface of high magneto-optical medium and silver metal using angular interrogation

In this manuscript, sensitivity of the surface plasmon polariton waves (SPPs) using angular interrogation is coherently manipulated at the interface of four level high magneto-optical medium and silver metal using prism geometry. The control and probe fields detuning, Rabi frequency and decay rate manipulated significantly the angular interrogation of sensitivity of the surface plasmon polariton waves. The permittivity ϵd and permeability μd of the high magneto-optical medium play an important role in the manipulation of the sensitivity. The sensitivity is a function of control field detuning. The maximum sensitivity is reported to 800 deg/RIU with control field detuning. The minimum sensitivity is investigated to 6 deg/RIU with probe field detuning and Rabi frequency of control field. The reported results have useful applications in data storage and chemical sensing technologies.

Thermo-optomechanically induced optical frequency comb in a whispering-gallery-mode resonator.

We present a theoretical study that combines thermal and optomechanical effects to investigate their influences on the formation of the optical frequency comb (OFC) in whispering-gallery-mode (WGM) microcavities. The results show that the cut-off order and center frequency of OFC affected by thermal effects exhibit an overall redshift by varying the power and detuning of the pump field, which provides the possibility of tuning the offset frequency of OFC. Our study demonstrates a method to characterize the effect on the generation of OFC and the tuning of its offset frequency in a WGM resonator with opto-thermo-mechanical properties and pave the way for the future development of OFC in thermo-optomechanical environments.

Modulatable all-optical logic gate in rubidium atoms using OAM

We experimentally demonstrate the intensity and angle control of interference image during all-optical logic (AOL) gate carrying orbital angular momentum (OAM) in a hot atomic ensemble. The variation of output signal intensity has been discovered by changing the detuning of input field. By changing the angle of reference light, we can also get obvious output signal modulation effects. Moreover, the transition of the interference pattern from parallel shape to spiral shape by changing the small angle is observed. This novel method of controlling AOL gate carrying OAM will further promoting the construction of all-optical networks with atomic ensembles.

Injected coherence and phase control in the tunneling of ultra slow three-level atoms

Our research aims to investigate the impact of injecting atomic coherence on the phase tunneling time of ultra slow cascade three-level atoms traversing through high-quality cavities. Prior to interacting with the cavity in the Fock state, the atoms are initially prepared in a superposition of the two upper levels. Our study has demonstrated that the coherence of the injected atoms can be tuned to control the phase time. Specifically, we have observed that the injected coherence can regulate the peak values and sub-superclassical nature of the traversal time. Moreover, we have investigated how the number of superclassical peaks and resonances in the tunneling time curve can be influenced by the cavity length and de Broglie waves of the atom. Additionally, we have discovered that the phase time behavior is not only affected by the center-of-mass (CM) motion but also by the atom–field detuning and the final internal state of the transmitted atoms. These findings have potential implications for developing and controlling ultracold atom-based technologies, such as quantum sensors, quantum information processing, and quantum simulation.

Many-body spin rotation by adiabatic passage in spin-1/2 XXZ chains of ultracold atoms

Quantum many-body phases offer unique properties and emergent phenomena, making them an active area of research. A promising approach for their experimental realization in model systems is to adiabatically follow the ground state of a quantum Hamiltonian from a product state of isolated particles to one that is strongly-correlated. Such protocols are relevant also more broadly in coherent quantum annealing and adiabatic quantum computing. Here we explore one such protocol in a system of ultracold atoms in an optical lattice. A fully magnetized state is connected to a correlated zero-magnetization state (an xy-ferromagnet) by a many-body spin rotation, realized by sweeping the detuning and power of a microwave field. The efficiency is characterized by applying a reverse sweep with a variable relative phase. We restore up to of the original magnetization independent of the relative phase, evidence for the formation of correlations. The protocol is limited by the many-body gap of the final state, which is inversely proportional to system size, and technical noise. Our experimental and theoretical studies highlight the potential and challenges for adiabatic preparation protocols to prepare many-body eigenstates of spin Hamiltonians.

Strong squeezing and robust entanglement in a second-order coupled optomechanical cavity assisted by a Kerr nonlinear medium

We investigate theoretically an optomechanical system composed of an optical mode and a mechanical mode interacting through first-order coupling and second-order coupling in the presence of a Kerr nonlinear medium. We study how the nonlinearities (second-order optomechanical coupling and Kerr nonlinearity) alter the optical output spectrum, optical quadrature squeezing and optomechanical entanglement. It is shown that the intensity of the output optical spectrum decreases drastically with an increase in second-order optomechanical coupling while it increases significantly with an increase in Kerr nonlinear parameter. More interestingly, by choosing suitable second-order optomechanical coupling and detuning of the optical cavity field, one can achieve strong squeezing of the cavity light field. Further, these nonlinearities play an important role in creating robust optomechanical entanglement between optical and mechanical modes. Hence, the presence of various nonlinearities in the system can be a good platform for achieving the squeezing of light and robust optomechanical entanglement which can be used in realizing better quantum optomechanical devices.

Effect of composite vortex beam on a two-dimensional gain assisted atomic grating

We propose an atomic grating based on an electromagnetically induced transparency phenomenon that switches between zeroth-order diffraction to a distinct higher-order diffraction pattern by driving a planar gaseous medium of a four-level tripod () atoms with three laser beams: modulation of standing wave control beam propagating nearly perpendicular to the planar medium, while vortex and weak plane probe beams directed perpendicular to the medium. We numerically investigate the behavior of the amplitude, phase modulations, and probe field diffraction intensities of different orders by the variation of the field detunings and orbital angular momentum number of the composite vortex light beam. Specifically, in the off-resonant case, the interplay between a square lattice of the control and an additional spatial variation of the vortex beam allows the emergence of higher diffraction orders and variable gain due to double transparency windows in this complex optical system. We believe that our proposed scheme might be useful in optical memory devices via the storage of information to diffraction orders of the atomic grating.

Optical-density enhanced quantum entanglement via four-wave mixing process.

We theoretically propose a scheme to generate a strong continuous-variable quantum entangled light source in four-wave mixing (FWM) process by increasing the optical density of atomic medium. By properly choosing the input coupling field Rabi frequency and detuning, the optimized entanglement can be achieved to be better than -17 dB at an optical density of approximately 1, 000, which has been realized in atomic media. Besides, with the optimized one-photon detuning and coupling Rabi frequency, the optimum entanglement degree can be greatly enhanced with the increment of optical density. We also examine the effects of atomic decoherence rate and two-photon detuning on entanglement in a realistic setting, and evaluate the experimental feasibility. We find that the entanglement can be further improved by considering two-photon detuning. In addition, with optimum parameters the entanglement is robust against the decoherence. The strong entanglement provides a promising applications in continuous-variable quantum communications.

Multiphoton blockade and antibunching in an optical cavity coupled with dipole-dipole-interacting Λ -type atoms

We study multiphoton blockade effects in a single-mode cavity interacting with two three-level atoms in $\Lambda$-configuration having position-dependent atom-field coupling. We consider the effects of dipole-dipole interaction (DDI) between the three-level atoms and show how the presence of DDI strongly influences the multiphoton blockade. For symmetric coupling of the atoms with the field, the DDI induces an asymmetry in the emission spectra as a function of pump field detuning. At positive detuning, the single-photon blockade gets stronger as a function of DDI strength, leading to photon antibunching. However, it becomes weaker at negative detuning and can also completely vanish. We show that this vanishing single-photon blockade is associated with a strong two-photon blockade, leading to two-photon bunching. Therefore, by just tuning the frequency of the pump field, we can achieve two very distinct features. We also study the effects of DDI when the atoms are asymmetrically coupled with the field and show that the proposed system exhibits two-photon bunching. We believe our results are important for the experimental realization of such systems where DDI may be present.

Two-dimensional electromagnetically induced grating via phase regulation in a closed-loop four-level atomic system

We proposed a theoretical scheme for two-dimensional (2D) electromagnetically induced grating (EIG) in a closed-loop four-level atomic system driven by a weak probe field, a traveling-wave control field, two orthogonal standing-wave fields and a microwave field. Due to low amplitude modulation accompanied with large phase modulation, EIG can be obtained and the probe energy can be diffracted into first-order and even high-order directions with high efficiency. The results show that the diffraction pattern and efficiency of the EIG could be adjusted effectively by the probe field detuning, the coherent field intensity, the interaction length. Meanwhile, the quantum interference between the amplitude modulation and phase modulation can be manipulated by the relative phase, which can be used to regulate the diffraction pattern and efficiency of the 2D EIG. Our scheme of 2D EIG may be useful in beam splitting and all-optical switching.

Nonlinear optical response of a strongly-driven quantum dot exciton-biexciton system

We examine the effective linear and the third-order nonlinear optical susceptibilities of an InAs/GaAs semiconductor quantum dot with a cascade exciton-biexciton configuration that is strongly driven by a nearly resonant pump electromagnetic field, while, at the same time, it interacts with a weak electromagnetic field. We assume that the applied fields are linearly polarized, which permits us to simplify the relative energy level diagram by using a three-level ladder-type scheme. We derive the equations of motion, in the dipole approximation, in a rotating frame, and follow an expansion approach to calculate the components of the density matrix which are associated to the effective linear and the self-Kerr third-order nonlinear optical susceptibilities. We present the spectra of the first-order susceptibility and the self-Kerr susceptibility and investigate the dependence of their profiles on the Rabi frequency and the detuning of the pump field, in the one-photon and the two-photon resonance regimes. The role of the biexciton energy shift on the susceptibilities is also studied. In addition, we present a dressed state analysis which appears to be crucial for obtaining a better understanding of several spectral properties of the susceptibilities.

Controlling Raman gain with atomic coherence

Raman gain is the optical gain generated by stimulated Raman scattering, which makes weak light amplify possible and can play an important role in weak light communication as well as related field. In this paper, experimentally and theoretically, we have observed the controllable Raman gain under the dressing effects in a coherently prepared N-type four-level atomic configuration. By controlling the detuning of the signal field and the coupling field, the electromagnetically induced transparency (EIT) window can be observed in the signal field. With the incidence of a strong pump laser into the atomic system, the two-photon ultranarrow fluorescence signal can overlap with EIT window by changing the frequency detuning of the pump field, meanwhile, a Raman gain can be induced by placing the signal field at possible large detuning. Such Raman gain can be effectively regulated and optimized by tuning the power of the signal field, pump field and the temperature of the atomic system so as to achieve higher contrast. The multi-parameter regulated higher contrast Raman gain with atomic coherence in atomic thermal system has potential applications in optical communication, superluminal laser and biophotonics.

Subpetahertz helicity modulation of attosecond pulse train using detuned two-color fields

We theoretically demonstrate a scheme to obtain an attosecond pulse train with subpetahertz helicity modulation, based on high harmonic generation driven by detuned two-color fields. As the waveform of the detuned two-color field varies with time, the attosecond pulse train switches periodically between left and right elliptical polarization in the temporal domain. The frequency of the helicity modulation can reach subpetahertz. In addition, by adjusting the frequency detuning of the two-color field, the modulation frequency can be continuously controlled. The scheme is expected to provide a useful light source to explore and manipulate a wide range of ultrafast dynamics in magnetic materials and chiral molecules.