Optical Bistability Behavior Research Articles

All-optical bistability based on cavity resonances in nonlinear photonic crystal slab-reflector-based Fabry–Perot cavity

In this paper, the optical bistability response of a nonlinear photonic crystal slab-reflector-based Fabry–Perot cavity (PhCS-FPC) based on cavity resonances was numerically simulated. Three-dimensional finite-difference time domain method (3D-FDTD) was applied to investigate the effect of the cavity length, wavelength, and maximum intensity of the incident light on the optical bistability behavior of PhCS-FPC around cavity resonances. Results showed that, by carefully adjusting the cavity length, operating wavelength, and maximum input intensity, an efficient optical bistable system at telecommunication wavelength (1550 nm) with a low threshold intensity of about 30 kW/cm2 is achieved. For the first time, numerical calculations showed that the bistable switching intensity and the width of the bistable region are dependent on the maximum intensity of the input field. Low bistable switching intensity, insensitivity to the polarization of the incident light, and the potential for on-chip photonic and electronic integration make PhCS-FPC a promising candidate for all-optical bistable devices.

Impact of geometry and magneto-optical properties on field enhancement and optical bistability in core\u2013shell nanoparticles

We study the interaction of electromagnetic field with two of the most tunable nanostructure geometries for nanoplasmonics including the magneto-optical nanoshell structure and the spheroidal geometry. We investigate the effect of combining both geometry and magneto-optical properties within the same nanostructure on the field enhancement factor and optical bistability behaviors. Since the coupling between the inner and outer surface plasmons of the nanoshell is stronger for the elongated spheroidal geometry as compared to that for the spherical case, field enhancement in ellipsoid nanoparticles is much more saleintiant. Moreover, the plasmonic field enhancement is four orders of magnitude larger for the spheroidal nanoshells as compared to spherical nanoshells. In addition to the appearance of optical bistability in this system, it is found that the threshold and window of bistability are strongly dependent on magneto-optical properties and geometry of the core–shell nanoparticle.

Optical bistability and multistability via both coherent and incoherent fields in a three-level system

We have investigated the optical bistability and multistability behaviors in a three-level V-type system via both coherent and incoherent fields inside a unidirectional ring cavity. We find that the appearance and disappearance of optical bistability (OB)/optical multistability (OM) can easily be controlled by adjusting systemic parameters. Our scheme opens up a new possibility for realizing transition from OB to OM or vice versa for potential applications in information networks and processing with increased capacity.

The effect of radio frequency on the optical bistability in Pr3+: Y2SiO5 crystal

We investigated theoretically the effect of an additional radio-frequency (rf) laser on the optical bistability (OB) behavior of the Pr[Formula: see text]: Y2SiO5 crystal. It is demonstrated that the rf field induces the OB behavior to the output of the system. It is shown that such OB behavior can be controlled by the intensity of either rf or coupling field.

Optical bistability of a plexcitonic system consisting of a quantum dot near a metallic nanorod

Optical response of a complex nanodimer comprising a semiconductor quantum dot via Coulomb interaction to a metal nanorod is analyzed theoretically. Optical bistability (OB) behavior of a coherently coupled exciton-plasmon (plexcitonic) hybrid system under a laser field is investigated. The bistable exciton population in a hybrid metal–semiconductor nanodimer response is shown, and it could be pointed out that OB behavior is strongly influenced by various parameters such as size of metal nanoparticle, interparticle distance as well as intensity of probe laser field. We show that OB can be observed for a plexcitonic system and depends strongly on the type of the metals which are good candidates for plasmonic applications. The numerical calculations show the gold nanorod exhibits significant optical bistability. The result promises various applications in the field of all-optical information processing at the nanoscale, the most basic of them being the optical switching, optical memory, optical transistor and optical logic.

Double-cavity optical bistability and all-optical switching in four-level N-type atomic system

We analyze the absorptive and hybrid absorptive–dispersive double-cavity optical bistability behavior in a four-level N-type atomic system driven by two optical fields circulating inside two independently unidirectional ring cavities and a trigger field outside the cavities. In this system, the two-photon absorption and cross Kerr nonlinearity play significant roles in the formation of bistability and can be controlled efficiently due to the quantum interference effect, and then the resulting nonlinear behavior exhibits different features from the two/three-level schemes. It is shown that the threshold values and hysteresis cycle width of the bistable curve can be manipulated via the adjustment of the system parameters. Meanwhile, we also obtain double-beam optical multistability. When adding positive and negative pulses to the cavity input, all-optical steady-state switching for the two cavity outputs can be achieved simultaneously. Therefore, the proposed scheme may have potential applications in all-optical communication and computing.

Optical bistability in a single-sided cavity coupled to a quantum channel

In this paper, we discuss the long wavelength optical reflection and bistable behavior of an InGaN/GaN quantum dot nanostructure coupled to a single-sided cavity. It is found that due to the presence of a strong coupling field, the reflection coefficient can be controlled at long wavelength, which is essential for adjusting the threshold of reflected optical bistability. Moreover, the phase shift features of the reflection pulse inside an electromagnetically induced transparency window are also discussed.

A convenient method for controlling transformation between optical bistability and multistability

We propose a convenient method to manipulate the behavior of optical bistability (OB) and optical multistability (OM) in a double Λ-type atomic system with hyperfine structure driven by a π-polarized probe field and a σ-polarized elliptically polarized field (EPF). In the scheme, the frequency detuning of two circularly polarized components of the EPF are determined by an applied magnetic field, and the amplitudes and the phase difference of that can be modulated by rotating a quarter-wave plate, which can be used to optimize quantum interference. Our numerical results show that not only the appearance and disappearance of OB can be transformed reciprocally, but also the switch from OB to OM or vice can be easily realized only by adjusting the magnetic field B or rotating the angle ϕ with the 1/4 wave plate.

A Novel Phase Sensitive Quantum Well Nanostructure Scheme for Controlling Optical Bistability

A novel four-level lambda-type quantum well (QW) nanostructure is proposed based on phase sensitive optical bistability (OB) and multistability (OM) with a closed-loop configuration. The influence of controlling parameters of the system on OB and OM is investigated. In particular, it is found that the OB behavior is strongly sensitive to the relative phase of applied fields. It is also shown that under certain parametric conditions, the OB can be switched to OM or vice versa. The controllability of OB/OM in such a QW nanostructure may bring some new possibilities for technological applications in solid-state quantum information science and optoelectronics.

Multilayer graphene based optical bistability

In this paper, optical bistability of multilayer graphene structures is proposed and investigated. Here, results show that in spite of reduction of the Fermi level, we have optical bistability behavior in multilayer graphene structures in comparison to a single layer one. Also, the hysteresis width and threshold values are adjustable. It should be mentioned that the layer numbers can be increased to specific numbers because of large loss and low on-state transmission due to electron–phonon relaxation time. Combination of the Fermi level and layer numbers provides us appropriate tuning to achieve desirable hysteresis width, threshold values, and on-state to off-state transmission ratio. Considering typical electron–phonon relaxation time of 1 ps, silicon as the dielectric medium, and the Fermi level about 0.7 eV, a structure with four graphene layers gives us on-state to off-state transmission ratio of about 11.48, on-state transmission of 0.31, and hysteresis width of 1.24 MV/m, which seems to be favorable at 1 THz and normal incidence condition. Our results support using multilayer graphene structures for future optical bistability-based low-power and tunable optical devices.

Intense blue upconversion emission and intrinsic optical bistability in Tm3+/Yb3+/Zn2+ tridoped YVO4 phosphors

Tm3+/Yb3+/Zn2+:yttrium metavanadate (YVO4) phosphors prepared through chemical coprecipitation and the solid state reaction method have been structurally characterized by an x-ray diffraction (XRD) study. Photoluminescence study of the developed phosphors under ultraviolet (UV) and near infrared (NIR) excitation has been performed. The excitation spectrum of the tetragonal zircon type YVO4 phosphors corresponding to the emission at ∼476 nm exhibits a broad excitation peak in the 250–350 nm region, which is due to charge distribution in the group. Under 980 nm CW diode laser excitation, enhancements of about ∼3000 times and ∼40 times have been observed for the blue band in the tridoped Tm3+Yb3+Zn2+:YVO4 phosphors compared to those of the Tm3+:YVO4 singly and Tm3+/Yb3+:YVO4 codoped phosphors, respectively. A downconversion (DC) emission study shows an enhancement of about ∼50 times for the blue band in the tridoped phosphors compared to that of the singly doped phosphors. Optical bistability (OB) behavior of the developed phosphors has been also investigated upon 980 nm excitation. The calculated Commission Internationale de l’Éclairage (CIE) color coordinates lie in the blue region with 96.5% color purity under 980 nm excitation, having a color temperature of ∼3400 K. Our observations show that the developed phosphors may be suitably used in dual mode luminescence spectroscopy, display devices, and UV LED chips.

Controllable optical bistability in a three-mode optomechanical system with atom-cavity-mirror couplings

We theoretically investigate the optical bistable behavior in a three-mode optomechanical system with atom-cavity-mirror couplings. The effects of the cavity-pump detuning and the pump power on the bistable behavior are discussed detailedly, the impacts of the atom-pump detuning and the atom-cavity coupling strength on the bistability of the system are also explored, and the influences of the cavity-resonator coupling strength and the cavity decay rate are also taken into consideration. The numerical results demonstrate that by tuning these parameters the bistable behavior of the system can be freely switched on or off, and the threshold of the pump power for the bistability as well as the bistable region width can also be effectively controlled. These results can find potential applications in optical bistable switch in the quantum information processing.

Optical bistability via an external control field in all-fiber ring cavity

We demonstrate a new scheme for realizing the Optical Bistability (OB) inside an all-fiber ring cavity with an external control field. In the absence of the external control field, the pump power is fixed below the threshold value of laser, and there is no laser in the cavity. However, when the control signal of 1505 nm to 1520 nm is injected into the cavity, laser begins to oscillate and OB appears. We found that the wavelength and power of the control signal can affect the OB behavior dramatically, which can be used to manipulate efficiently the threshold intensity and the hysteresis loop. We also give an explanation of the bistability phenomenon based on numerical simulations, which are agreed very well with our experimental results. Our scheme may provide some new possibilities for technological applications in optical power limiters, switches or memories.

Optical bistability forming due to a Rydberg state

We consider the behavior of optical bistability (OB) and multistability (OM) in a four-level atomic system involving a Rydberg state illuminated by a probe field as well as control and switching laser beams of larger intensity. When the switching field is absent, no OB arises because of the effect of Rydberg electromagnetically induced transparency. However, by application of the switching field, the hysteresis cycle appears to give rise to optical bistability, thanks to Rydberg electromagnetically induced absorption. It is further demonstrated that one can efficiently modify the OB threshold via suitable choices of system-controlling parameters. Interestingly, it is observed that this model can produce an optical switching between OB and OM with potential applications in logic-gate devices for optical communication.

Control of optical bistability in the nonlinear regime of two-sided cavity quantum electrodynamics

We investigate the optical bistability behavior of a two-sided cavity quantum electrodynamics system. The non-linear input - output relation of the atom - cavity system coupled by two input light fields from two ends of the cavity can be controlled by a control light from the free space. Different from the common optical bistability phenomenon in the atom - cavity system, two separate bistability regions are observed. The bistability threshold and hysteresis loop can be well controlled by the control light. Because of field interference, the output light intensity becomes different with varying the relative phase of two incident fields. The output field intensity at the threshold of the first bistability region approaches zero with either increasing the detuning or lowering the intensity of the control light; thus, the perfect photon absorption condition is extended and a broadband near-perfect photon absorber is realized. Furthermore, we show an asymmetrical transmission feature due to field interference. (C) 2017 Optical Society of America

Multiple spontaneously generated coherence and phase control of optical bistability and multistability in a tripod four-level atomic medium.

Optical bistability (OB) and optical multistability (OM) behaviors induced by multiple spontaneously generated coherence (SGC) are investigated theoretically in a tripod four-level atomic scheme. It is found that OB or OM is sensitive to the SGC effects, and the thresholds of OB can be controlled via changing the strength of multiple SGC or the relative phases of the applied fields. In addition, we can switch OB to OM by adjusting the twofold relative phases of the applied fields or vice versa.

Toggle switch from optical bistability to multistability via an elliptically polarized field

In this paper, we propose a scheme for manipulating the behavior of optical bistability (OB) and optical multistability (OM) in an N-type four-level atomic system. In the scheme, quantum interference is optimized by the left-handed and the right-handed fields of an elliptically polarized field (EPF). The threshold and the hysteresis cycle shape of OB and OM can be controlled by modulating the intensity of the EPF. Especially, the transition from OB to OM or vice versa can also be easily realized by proper tuning the phase difference between the left-handed and right-handed polarized fields under the optimal intensity of the EPF.

Comparison between optical bistabilities versus power and frequency in a composite cavity-atom system.

By making use of the changes in optical properties such as absorption and dispersion around the resonance generated via electromagnetically induced transparency (EIT), we theoretically and experimentally investigate a "∞"-shape optical bistability (OB) versus frequency on the probe transmission with a Λ-shape EIT window in a rubidium atomic ensemble confined in a three-mirror optical ring cavity. Compared to the traditional OB reflected by a hysteresis loop versus power, such newly demonstrated optical bistable behavior (represented by a "∞"-shape non-overlapping region) by scanning probe and cavity detuning can experience dual bistabilities and be more sensitive to the change of experimental parameters. Further, we study the relationship between vacuum Rabi splitting and the "∞"-shape OB. Such study on frequency-induced OB could effectively improve the applications related to OB such as logic-gate devices and optical information processing.

Intrinsic optical bistability in doped polymer

One of the most interesting and applicable effects of nonlinear optics is optical bistability. This phenomenon is exhibited by certain resonant optical structures where it is possible to have two stable steady transmission states for the device, depending on the history of the input. Such a bistable device may be useful for optical computing elements as a result of its memory characteristics. Optical bistability behaviour is usually observed by inserting a nonlinear matter inside a Fabry–Perot interferometer. But in this study, it was shown that this can be achieved without the application of any optical resonator. Two laser beams were used to interact with the photorefractive media (doped PMMA polymer) which resulted in the bistability of the intensity of transmitted wave. Feedback was provided by a periodic grating created in the photorefractive polymer PMMA.

Influence of Anisotropy on Optical Bistability in Plasmonic Nanoparticles with Cylindrical Symmetry

In this paper, the effect of radial anisotropy on optical bistability in the cylindrical nanoshells is theoretically investigated within the quasi-static approximation. We consider two cases: when the shell is anisotropic and the core is nonlinear metal and when the core is anisotropic and the shell is a nonlinear metal. The dependence of optical bistability on the size of the nonlinear/anisotropic shell or core, the embedding medium, the anisotropy parameter, and the type of noble metals as candidates for plasmonics is studied and demonstrated. We show that by changing the type of the plasmonic metal, the switching threshold field changes can be used to design nanoparticle-based all-optical sensors. It is also shown that significant optical bistability and all-optical switching behavior can be obtained in the cylindrical nanoshells due to nonlinearity enhancement via the plasmonic structure.