Optical Multistability Research Articles

Two-channel optical bistability and multistability in a degenerate four-level atomic medium under a static magnetic field

In this paper, we study the formation of optical bistability (OB) and optical multistability (OM) in a degenerate four-level atomic system by an external magnetic field that is excited by a probe laser field, a coupling laser field and a signal laser field. The coupling field can cause electromagnetically induced transparency (EIT) for the probe field in the atomic medium, while the signal field and/or external magnetic field can switch between single-EIT and two-EIT regimes. Based on these properties, OB and OM effects can be formed at two different frequency regions of the probe field (two channels). By adjusting the magnetic field or the intensity and the frequency of laser fields, the threshold intensity and the width of OB or OM can also be changed simply. The model can be useful for experimental observations and applications in modern photonic devices.

Ultra low-power multistability in [formula omitted]-symmetric periodic structures with saturable coupling, gain and loss

The present work investigates the switching dynamics of conventional fiber Bragg gratings (FBGs) with saturable coupling and parity-time (PT)-symmetric fiber Bragg gratings (PTFBGs) with saturable coupling (SC) and saturable gain-loss (SGL) in the presence of Kerr nonlinearity (KNL) [model - I] and saturable nonlinearity (SNL) [model - II]. Both system models can generate distinct optical multistability (OM) and bistability (OB) curves, including S-shaped, ramp-like, and mixed OM curves in both unbroken and broken PT-symmetric regimes. The impact of each control parameter on controlling switching intensities, hysteresis width, and the number of stable states is thoroughly examined for both of these system models. The direction of right light incidence enables a significant reduction in the switching intensities to below 100 W/cm2, the lowest critical power ever reported in the literature of PTFBGs, thanks to the concept of both saturable coupling, gain and loss.

Controllable optical bistability and multistability in a V-type three-level atomic system interacting with two broadband independent squeezed baths

In this study, we investigate the optical bistability (OB) and optical multistability (OM) phenomena within a V-type three-level atomic system interacting with two independent broadband squeezed baths confined in a unidirectional cavity. Our analysis reveals that the transition between OB and OM is influenced by the strength of the control field and the intensity of the squeezed vacuum. Notably, the impact of each of these factors on the transition exhibits distinct characteristics. Furthermore, we explore the effects of additional system parameters, such as the incoherent pumping rate and cooperation parameter. Our findings emphasize the crucial roles played by these parameters in shaping the observed results. Specifically, we observe that variations in the incoherent pumping rate and cooperation parameter contribute significantly to the system’s OB and OM behavior, further underscoring the multifaceted nature of the studied atomic system. This comprehensive investigation not only elucidates the intricate interplay between key parameters but also unveils the sensitivity of the system to variations in control field strength, intensity of the squeezed vacuum, incoherent pumping rate, and cooperation parameter.

Optical solitons, qualitative analysis and multistability response to study the dynamical behaviour of light wave promulgation

Our aim is to explore novel optical solitons within the context of an extended higher-order nonlinear Schrödinger equation that governs the behaviour of propagating light waves. Primarily, this research finds abundant types of solitons, such as singular, kink and trigonometric functions subject to certain constraint conditions. We have utilized G ′ / ( b G ′ + G + a ) -expansion method, which has proved effective in retrieving these solitons and presenting them for further analysis. The model's dynamic behaviour is then investigated through bifurcation, quasi-periodic oscillations, chaotic behaviour, and sensitivity. These include methods like phase portrait rendering, time series scrutiny, Lyapunov exponents calculation, and the assessment of multi-stability. Finally, sensitivity analysis is conducted at three distinct initial conditions, revealing that the model displays a high level of sensitivity, with substantial alterations occurring in response to minor changes in the initial conditions. The results of this study are revolutionary, intriguing, and possess crucial theoretical importance in evolution disruptions.

Dynamics of twin pulse propagation and dual-optical switching in a Λ + Ξ atomic medium

Optical bistability (OB) and optical multistability (OM) as well as optical soliton and all-optical switching have been successfully established in a lambda + cascade-type five-level atomic medium under electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) regimes. For this configuration, three laser fields are required to excite atomic transitions. The probe laser field with two circularly left- and right-polarized components excites atoms in a lambda-type configuration. Meanwhile, two coupling laser fields excite atoms in a ladder-type configuration. In this way, the above optical phenomena can occur with two frequency channels corresponding to the circularly left- and right-polarized light components. By adjusting the strength/direction of the static magnetic field in the presence of the driving field, the EIT and EIA effects can be swapped, at the same time, OB and OM effects can also be converted. In the EIT regime, the propagation of the probe pulse easily achieves the soliton state, whereas it can be completely extinguished in the EIA regime. This makes it easy to create an all-optical switching mechanism. Especially, both components of the probe field (cw) can be modulated into a synchronous or asynchronous square pulse according to the modulation of the driving field. The results obtained from the investigated model may provide merits of the applications for optical storage and all-optical switching for multi-channel optical communications.

Optical bistability and multistability with coupled quantum wells in the presence of second- and third-order nonlinearities

In this work, we explore the intriguing phenomena of bistability and multistability in a cavity comprising two coupled quantum wells via electron tunneling. The cavity is driven by squeezed light produced by an optical parametric oscillator. Our results show that the frequency detunings relative to direct and indirect excitons are crucial for the occurrence of bistability, which is governed by the Kerr effects. Furthermore, we reveal that multistable behavior in the excitonic and photonic intensities can be attributed to the interaction between second- and third-order nonlinearities. We also investigate the controllability of the transition between bistability and multistability. The switch between bistability and multistability is controlled by adjusting the squeezed light’s amplitude or the cavity’s frequency detuning between the external coherent drive and the cavity. The tunneling has a contrasting double impact for the emergence or destruction of bistability and multistability, depending on the consideration of direct and indirect exciton nonlinearities. As a consequence, the switch between bistability and multistability can be ensured also by adjusting the tunneling rate between the wells, which in turn depends on the distance separating them.

Controlling optical bistability, multistability and all-optical switching through multi-photon excitation process

We present a theoretical study on optical bistability (OB), optical multistability (OM) and tunable all-optical switching in a four-level cascade type atomic system. The density matrix formalism is used to find out the response of the probe laser field. We explore OB and OM under unidirectional optical ring cavity configuration. A comparison between the effects of electromagnetically induced transparency and electromagnetically induced absorption windows on OB is presented. The threshold of OB and the hysteresis width can be tuned effectively by adjusting the applied coherent fields. A transition from OB to OM and vice-versa can be easily achieved by tuning the field parameters and the atomic cooperation parameter. Dynamic control of the probe laser propagating through the medium has been investigated. We also demonstrate conversion of a continuous wave input probe field into output switched pulse. The ON/OFF time of the switched probe pulse can also be controlled by tuning the field parameters.

Low-temperature optical bistability and multistability in superconducting photonic multilayers with graphene

Optical bistability and multistability are numerically investigated based on periodic superconducting photonic multilayers with graphene in cryogenic environments. Bandgap edge resonances are sensitive to circumstance temperature and can localize the electric field greatly, which is utilized to enhance the nonlinearity of graphene. Consequently, low threshold optical bistability and double-bistability are realized. Optical multistability subsequently arises by increasing the value of circumstance temperature as well. The thresholds of bistability and multistability lower further by decreasing the chemical potential of graphene or promoting the period number of photonic multilayers. The thresholds can be decreased as low as several hundred MW/cm2. The complex structure has a great potential for the development of two- and multiple-valued all-optical switches in low-temperature condition.

Optical bistability and multistability in hybrid system

In this letter, a comprehensive investigation has been conducted on the optical bistability (OB) and optical multistability (OM) phenomena manifested by transmitted light in a ring cavity consisting of a hybrid system of metal nanoparticle (MNP) and semiconductor quantum dot (SQD). Our study has been primarily devoted to examining the influence of the distance between SQD and MNP, as well as the susceptibilities of the SQD, the MNP, and the hybrid nanostructure as a whole, on the OB and OM traits of the transmitted light. Our discoveries demonstrate that a transition from OB to OM, or vice versa, can be accomplished for a definite distance between MNP and QD. It is our contention that our proposed model may have potential applications in the domain of quantum information processes based on SQD-MNP hybrid systems.

Transition from optical bistability to multistability in a tunneling quantum dot via structure hybrid light

In this paper, we proposed a new model based on the electron tunneling effect in a four-level quantum dot molecule (QDM) for studying the optical bistability (OB) and optical multistability (OM). The QDM interacts with a probe and two coupling and Laguerre–Gaussian (LG) fields. We found that by adjusting the electron tunneling effect and the parametric controlling of LG light, the transition from OB to OM or vice versa is possible. Moreover, due to the simultaneous interaction between coupling and LG lights with the same optical transition adjusting the threshold of OB and OM by orbital angular momentum (OAM) of the LG light becomes achievable. Our results show that by adjusting the simultaneous effect of electron tunneling and OAM state of the vortex light, the favorable OB and OM patterns with adjustable intensity thresholds are achievable. Our proposed model may have potential application in quantum information science based on quantum dot (QD) devices.

All-optical control of optical bistability in a hybrid system

In this paper, we study the tunneling induced optical bistability (OB) in a quantum dot (QD)-metallic nanoparticle (MNP) hybrid system via surface plasmon effects. We realized that in the presence of the tunneling effect, OB arises when the probe light is parallel to the major axis of the hybrid system. We realized the threshold of OB can be controlled by controlling the distance parameter between the QD and MNP. For appropriate distance between the QD and MNP, we find that optical multistability (OM) appears in the system. We find that the threshold of OM can be adjusted when we consider the radius effect of the MNP, respectively.

Controlling of optical bistability and multistability via two different incoherent processes

In this paper, we investigate the optical bistability (OB) and optical multistability (OM) phenomena for a quantum dot nanostructure via two different mechanisms. The first process is based on the application of the incoherent pumping field while the second one is due to the ratio between the injection and cavity injection rates. We show that the appearance of OB and OM properties in the system depends strongly on the presence of these mechanisms. It is found that OB appears in the presence of both mechanisms, but OM appears only when both mechanisms are present in the system simultaneously. We also study the linear absorption behaviors for the case when OB and OM are observed in the system. It is shown that for the multistable state, the absorption properties of the system are different from the bistable state, which has a strong dependence on incoherent processes.

External magnetic field-assisted polarization-dependent optical bistability and multistability in a degenerate two-level EIT medium

In this paper, a novel degenerate two-level model is proposed to study the behavior of optical bistability (OB) and optical multistability (OM) under the effect of the magnetic field and relative phase. We show that the behavior of the OB can appear in the resonant regime by changing the strength of the external magnetic field. Especially, the result has shown that it is possible to easily convert between OB and OM by adjusting the strength of the external magnetic field or coupling field in the presence of the relative phase. In addition, the influence of the probe detuning and the atomic cooperation parameter on the OB behavior have also been considered. The studied results may be helpful for optical communication applications in optical switching processing and optimization.

Tunable optical multistability and absorption in a hybrid optomechanical system assisted by an auxiliary cavity and quantum dot molecules

Coherent and tunable light-matter interaction in cavity quantum electrodynamics (C-QED) has attracted much attention for its fundamental importance and applications in emerging areas of quantum technologies. In this work, we propose a hybrid C-QED system comprising embedded quantum dot molecules (QDMs) in a primary photonic crystal (PhC) optomechanical cavity, which is further coupled to an auxiliary PhC cavity via a single-mode waveguide. We investigate the effect of the QDMs, mechanical oscillator, and the feedback from the auxiliary cavity on the multistability response shown by the mean intracavity photons in the primary optomechanical cavity. Tuning the various system parameters can control optical multistability. We further study the absorption spectra showing distinct characteristics of negative absorption (transparency dip), which strongly depend on mechanical resonator frequency. Thus, the proposed model is valuable for practically realizing efficient all-optical switching devices at low power and in various other quantum sensing devices.

Nonlinear effects of quadratic coupling in optical multistability and controllable transparency of a hybrid optomechanical system consisting of quantum dot molecules

Nonlinear effects of quadratic coupling in optical multistability and controllable transparency of a hybrid optomechanical system consisting of quantum dot molecules

Nonclassical correlated optical multistability at low photon level for cavity electromagnetically induced transparency

We study the nonequilibrium dynamic behaviors in a driven-dissipative single-atom cavity electromagnetically induced transparency. The optical bistability and multistability beyond a Kerr nonlinearity are observed utilizing the optical Stark shift induced strong nonlinearity. We show that the nonequilibrium dynamical phase transition between bistability and multistability is highly tunable by the system parameters in a large parameter region. The first-order dissipative optical bistability (multistability) always corresponds to the photon-bunching quantum statistics, which indicates that the quantum fluctuations and correlations play important roles in nonequilibrium dynamics. Interestingly, bistability and multistability with photon-bunching quantum statistics occurring at extremely low steady-state cavity photon number are observed, even under a very strong cavity driven field. Furthermore, we demonstrate that the unique cavity steady-state solution of the full quantum calculation is excellently consistent with the lowest solution based on the semiclassical mean-field approach in bistability and multistability regimes when the cavity photon number is much less than unity, albeit these nonclassical quantum states should possess strong quantum fluctuations in this parameter regime. Our results pave the way to exploring nonclassical correlated optical multistability in quantum regime, which may bring exciting opportunities for potential applications from quantum information processing to quantum metrology.

Optical bistability and multistability via electron injection rate in an imperfect cavity

In this letter, we investigate the electron injection rate-based optical bistability (OB) and optical multistability (OM) features in an imperfect cavity. Coherent optical fields interact with the open four-level quantum system that makes up the ring cavity. We have discovered that the threshold of OB and OM as well as the length of the hysteresis loop can be changed by varying the length of the quantum system, reflection and transmission coefficient of cavity mirrors. Our findings further show that the electronic exit rate from the cavity and the electron injection rates have a significant impact on the threshold of OB and OM. It is discovered that transitioning from OB to OM or vice versa is achievable by adjusting the controllable parameters. The impact of the cooperation parameter on the properties of the OB and OM is then addressed. The findings demonstrate that the OB features are simple to manipulate. Our suggested model might be used to develop an all-optical device for use in upcoming quantum information processing.

Optical switching in composite media containing nonlinear plasmonic coated particles with radial anisotropy

We investigate the nonlinear optical properties of the composite with identical radial-anisotropic/ nonlinear-plasmonic core-shell spherical inclusions randomly embedded in the linear medium. In the weakly-nonlinear case, the enhanced effective third-order nonlinear susceptibility is achieved through the exhibited surface plasmon resonance, and the enhanced peak can be tuned by adjusting the anisotropic parameter. In the strong-nonlinear case, the single optical bistability, double optical bistability or optical tristability in small particles will be found. Furthermore, we demonstrate the optical multistability arising from the high-order modes in low-index surrounding environment for the large particles. And the anisotropy is essential to expand the diversity of the optical switching. Our results are envisioned for the opportunities of anisotropic materials and the applications of the optical switching.

Realization of phase dependent optical bistability in a quantum dot molecule via three-wave mixing

In this paper, we have proposed a new model based on the electron tunneling effect for controlling the optical bistability (OB) and optical multistability (OM) in a defect slab structure with a quantum dot molecule (QDM). Due to the presence of the electron tunneling effect, an additional weak signal beam can be generated in the system which makes the medium becomes phase dependent. We have studied the refractive index properties of the QDM via optical susceptibility of the propagated probe light. We have discussed the relative phase effect on negative refractive index (NRI) of the QDM nanostructure due to presence of electron tunneling. Then, by using the transfer matrix method, we have studied the transmission coefficient for NRI of the QDM nanostructure. Then, we have investigated the properties of transmitted light versus incident light for realizing the OB and OM. We have considered the relative phase effect on OB and OM properties of the transmitted beam and find that the switching between them is possible when electron tunneling is present in the quantum dot. Moreover, the optical thickness of the defect layer is also investigated on OB and OM in resonance and non-resonance conditions.

Optical bistability in a negative refractive index media using the electron tunneling effect

In this letter, we proposed a brand-new version for investigating the optical bistability (OB) and optical multistability (OM) through electron tunneling impact in a defect one-dimensional photonic crystal (1DPC). The defect layer of 1DPC is doped with double quantum dot (DQD) nanostructure which interacts with an indirect incoherent pump and a susceptible probe incident light, respectively. By the usage of the quantum mechanical density matrix method, we first examine the refractive index properties of the defect layer through electron tunneling and indirect incoherent pumping effects. Then, through the usage of the transfer matrix methods, we acquire the reflection and transmission coefficients of the defect 1DPC. At the end, we discuss the OB and OM properties of the reflected and transmitted lighting in negative refractive index situation of the DQD. We determine that during a few parametric conditions the switching from OB to OM or vice versa is feasible for reflected and transmitted light beams.